601.01 601-1
Division 600
MISCELLANEOUS CONSTRUCTION STRUCTURAL CONCRETE DESCRIPTION
601.01 This work consists of furnishing and placing hydraulic cement concrete per these
specifications and in conformity with the lines, grades , and dimensions as shown on the plans or established. This work includes preparing concrete surfaces designated in the Contract and applying an approved color ed Structural Concrete Coating .
601.02 Classification. The classes of concrete shown in Table 601 -1 shall be used when
specified in the Contract. 601.02 601-2 Table 601 -1 CONCRETE FIELD REQUIR EMENTS Concrete Class Required Field Compressive Strength (psi) Air Content: % Range (Total) Slump # Maximum Water/Cementitio us Material (w/cm) Ratio: B 4500 at 28 days 5 - 8 +/- 2” of Form 1373 Slump w/cm on Form BZ 4000 at 28 days N/A* 6” – 9” w/cm on Form D 4500 at 28 days 5 – 8 +/- 2” of Form 1373 Slump w/cm on Form DF 4500 at 28 days 4 - 8 +/- 2” of Form 1373 Slump w/cm on Form DT 4500 at 28 days 5 – 8 +/- 2” of Form 1373 Slump w/cm on Form PS (Girders) 8500 at 28 days N/A* 9” maximum 0.45 PS (Deck Panels) 6000 at 28 days N/A* 9” maximum 0.45 P 4500 at 28 days 4 – 8 +/- 2” of Form 1373 Slump w/cm on Form S35 5000 at 28 days 5 – 8 +/- 2” of Form 1373 Slump w/cm on Form S40 5800 at 28 days 5 – 8 +/- 2” of Form 1373 Slump w/cm on Form S50 7250 at 28 days 5 – 8 +/- 2” of Form 1373 Slump w/cm on Form Shotcrete 4500 at 28 days 7-10^ N/A 0.45 Table 601 -1 Notes: * 5 - 8% when specified. # Slump shall be a maximum of 9.0 inches for all classes of concrete. Concrete may have a slump above 9.0 inches when designed as Self Consolidating Concrete (SCC). The requirements for slump flow, blocking assessment, and segregation shall apply. ^ Before pumping for wet process. 601.02 601-3 Class B concrete is air -entrained concrete for general use. Class D or P concrete may be substituted for Class B concrete. Additional requirements are:
1.The coarse aggregate shall have a nominal maximum size of 1 1/2 inches or smaller.
2.Class B Concrete for Slope and Ditch Paving shall be macro -fiber reinforced. Class BZ concrete is concrete for drilled shafts. Additional requirements are:
1.Entrained air is not required unless specified in the Contract. When entrained air is specified in the Contract, the air content shall be 5 to 8 percent.
2.Slump shall be a minimum of 6 inches and a maximum of 9 inches. A minimum slump of 6 inches shall be maintained during the anticipated pour period. The use of retarders and hydration stabilizers are allowed to extend the slump life of the concrete. When the Contractor elects to use SCC, the slump requirement for Class BZ Concrete does not apply.
3.The coarse aggregate size shall be AASHTO M43 size #8 unless otherwise approved by the Engineer.
4.The mix shall either have a permeability not exceeding 2,500 coulombs at an age of not more than 56 days when tested per ASTM C1202 or have a surface resistivity of at least 12 kΩ-cm at 28 days using AASHTO T358.
5.The unrestrained shrinkage shall not exceed 0.050 percent at 28 days when tested by CP -L 4103. Class D concrete is a denser general use concrete. Additional requirements are:
1.The mix shall either have a permeability not exceeding 2,500 coulombs at an age of not more than 56 days when tested per ASTM C1202 or have a surface resistivity of at least 12 kΩ-cm at 28 days using AASHTO T358.
2.The unrestrained shrinkage shall not exceed 0.050 percent at 28 days when tested by CP -L 4103.
3.The mix may use an optimized gradation (OG) with a nominal maximum aggregate size of at least 3/4 inch.
4.The mix shall have a nominal maximum aggregate size of at least ¾ inch if an OG is not used.
5.When used in slip forming, an edge slump less than 6 mm (0.25 in.) and less than 30 percent surface voids (ranking of 2 or less) is required. The box test is described in CP 63.
6.Class D Concrete for sidewalks on bridge decks and bridge rail shall be macro -fiber reinforced. Class DF concrete is a macro fiber -reinforced concrete. Additional requirements are:
1.The concrete mix shall include approved macro or hybrid polyolefin fibers at a minimum dosage of 4 lb/ cy, or the minimum dosage specified on the Department’s Approved Product List (APL), whichever is greater.
2.The unrestrained shrinkage shall not exceed 0.050 percent at 28 days when tested by CP -L 4103.
3.The mix shall either have a permeability not exceeding 2,500 coulombs at an age of not more than 56 days when tested per ASTM C1202 or have a surface resistivity of at least 12 kΩ-cm at 28 days using AASHTO T358. 601.02 601-4
4.The mix may use an OG with a nominal maximum aggregate size of at least 3/4 inch.
5.The mix shall have a nominal maximum aggregate size of at least 3/4 inch if an OG is not used.
6.When used in slip forming, an edge slump less than 6 mm (0.25 in.) and less than 30 percent surface voids (ranking of 2 or less) is required. The box test is described in CP 63.
7.Shrinkage reducing admixtures may be incorporated into the mix.
8.An expansive cement additive may be added to an ASTM C150 Type I/II cement and fly ash to produce an ASTM C845 Type K cement. The proportion of the expansive cement additive will be determined by testing the cementitious material blend per ASTM C806. The blended material shall have an expansion of 0.04 to 0.10 percent at 7 days when tested per ASTM C806 . When an expansive cement is used, the w/cm ratio shall be 0.45 to 0.55 and t he expansion of the laboratory trial mix shall be 0.05 to 0.09 percent at 7 d ays when tested per ASTM C878. Class DT concrete is used for bridge deck resurfacing. Additional requirements are:
1.The concrete mix shall consist of a minimum of 50 percent AASHTO M 43 size No. 7 or No. 8 coarse aggregate by weight of total aggregate.
2.The mix shall either have a permeability not exceeding 2,500 coulombs at an age of not more than 56 days when tested per ASTM C1202 or have a surface resistivity of at least 12 kΩ-cm at 28 days using AASHTO T358.
3.The unrestrained shrinkage shall not exceed 0.050 percent at 28 days when tested by CP - L 4103. Class P concrete is used in pavements. Additional requirements are: (1) The Required Field Flexural Strength shall be 650 psi.
2.The concrete mix shall consist of a minimum 55 percent AASHTO M 43 sizes No. 57, No. 6, No. 67, No. 357, or No. 467 coarse aggregate by weight of total aggregate.
3.The mix may use an OG with a nominal maximum aggregate size of at least ¾ inch.
4.ASTM C150 Type III cement may be used for early opening.
5.The mix shall either have a permeability not exceeding 2,500 coulombs at an age of not more than 56 days when tested per ASTM C1202 or have a surface resistivity of at least 12 kΩ-cm at 28 days using AASHTO T358.
6.The unrestrained shrinkage shall not exceed 0.050 percent at 28 days when tested by CP - L 4103.
7.When concrete is to be placed using a paver, an edge slump less than 6 mm (0.25 in.) and less than 30 percent surface voids (ranking of 2 or less) is required. The box test is described in CP 63.
8.A minimum of 20 percent Class F fly ash or High Reactivity Pozzolan or 30 percent Slag cement by weight shall be used to replace any ASTM C150 cement, or ASTM C595 Type IL cement. ASTM C595 Type IT(MS), IT(HS), IP(MS) or IP(HS) cements may be used without cement substitutions. Class C fly ash may be used if the calcium oxychloride is determined to be less than 15 g CaOXY/100 g cementitious paste as determined per AASHTO T 365 for Class 0 Sulfate Exposure. Class PS Class PS concrete is used for prestressed concrete members. Requirements for Class PS concrete are specified in subsection 618.11. ASTM C150 Type III cement may be used. 601.03 601-5 Class S35, S40, and S50 concretes are dense, high-strength concretes. Additional requirements are:
1.The concrete mix shall be made with AASHTO M 43 sizes No. 57, No. 6, No. 67, No. 7 , or No. 8 coarse aggregate.
2.When placed in a bridge deck, the mix shall have a nominal maximum aggregate size of at least 3/4 inch.
3.The mixes may use an OG with a nominal maximum aggregate size of at least 3/4 inch.
4.For S35 and S40 concretes, the unrestrained shrinkage shall not exceed 0.050 percent at 28 days when tested by CP -L 4103.
5.For S50 concretes, the unrestrained shrinkage shall not exceed 0.040 percent at 28 days when tested by CP -L 4103.
6.For S35 and S40 concretes, the mix shall either have a permeability not exceeding 2,000 coulombs at an age of not more than 56 days when tested per ASTM C1202 or have a surface resistivity of at least 14 kΩ -cm at 28 days using AASHTO T358.
7.For S50 concrete, the mix shall either have a permeability not exceeding 1,500 coulombs at an age of not more than 56 days when tested per ASTM C1202 or have a surface resistivity of at least 18 kΩ -cm at 28 days using AASHTO T358. Class Shotcrete concrete is used for shotcrete applications. Additional requirements are:
1.The required air content before the pump for wet process applications shall be 7 –10 percent.
2.Additional requirements are listed in subsection 641.02. The Contractor may design Class B, Class BZ, Class D, Class PS, Class S35, Class S40, and Class S50 concrete to be Self Consolidating Concrete (SCC) with the following requirements:
1.SCC shall have a slump flow of 20 to 26 inches when tested per ASTM C1611 using an inverted slump cone.
2.SCC shall have a maximum blocking assessment of 2.0 inches when tested per ASTM C1621.
3.SCC shall have a maximum static segregation of 10 percent when tested per ASTM C1610. MATERIALS
601.03 Materials shall meet the requirements specified in the following subsections:
Fine Aggregate 703.01 Coarse Aggregate 703.02 Portland Cement 701.01 Fly Ash 701.02 Silica Fume 701.03 Water 712.01 Air Entraining 711.02 Pigments and 711.03 Curing Materials 711.01 Preformed Joint 705.01 Reinforcing Steel 709.01 Bearing Materials 705.06 Epoxy 712.10 Structural Concrete 708.08 High-reactivity 701.04 Slag Cement 701.05 601.04 601-6 Pozzolans shall consist of fly ash, silica fume, and high -reactivity pozzolan. Prestressing steel shall meet the requirements of subsection 714.01 except as noted on the plans. Calcium Chloride shall not be used in reinforced concrete. Calcium Chloride shall be used in non-reinforced concrete only when specified. Where Fiber -Reinforced Concrete is specified or designated on the plans, the concrete mix shall include approved polyolefin fibers. Unless otherwise specified, a minimum of 1.5 pounds or the manufacturer’s recommended dose per cubic yard of polyolefin fiber reinforcement shall be evenly distributed into the mix. Mixing shall be as recommended by the manufacturer such that the fibers do not ball up. Polyolefin fibers shall meet the requirements of ASTM C1116 and ASTM D7508. Where Macro Fiber -Reinforced Concrete is specified or designated on the plans, the concrete mix shall include approved macro or hybrid polyolefin fibers at a minimum dosage of 4 lb/cy or the minimum dosage specified on the APL, whichever is greater. The dosage of the fiber may be reduced if trial mix data shows a minimum residual strength of 150 psi as determined per ASTM C1609 using a load support apparatus compliant with the requirements of ASTM C1812, “Standard Practice for Design of Journal Bearing Supports to be Used in Fiber Reinforced Concrete Beam Tests.” Mixing shall be as recommended by the manufacturer such that the fibers are evenly distributed in the mix and do not ball up. Macro or hybrid polyolefin fibers shall meet the requirements of ASTM C1 116 and ASTM D7508.
601.04 Sulfate Resistance. The Contractor shall provide protection against sulfate attack
on concrete structures and pavements by providing concrete manufactured according to the requirements of the specified Sulfate Exposure Class. The sulfate exposure class for all concrete except Class PS shall be Class 2 unless otherwise specified on the plans. The sulfate exposure class for Class PS shall be Class 0. The requirements for a higher sulfate exposure class may be used for lower sulfate exposure classes. The Contractor may request to test the soil and water at a structure location to change the sulfate exposure class. Testing and sampling of the location shall be at a frequency approved by the Engineer, in consultation with the Region Materials Engineer. If the Contractor provided test reports that show another class of exposure exists at a structure location, the Engineer may accept a concrete mix for that location at the changed sulfate exposure class. Cementitious material requirements for each Sulfate Exposure Class are as follows: Class 0 requires that the concrete have a maximum Water/Cementitious Material Ratio of 0.45 and one of the following:
1.ASTM C150 Type I, II, III, or V
2.ASTM C595 Type IL, IP, IP(MS), IP(HS), or IT 601.04 601-7 Class 1 requires that the concrete have a maximum Water/Cementitious Material Ratio of 0.45 and one of the following:
1.ASTM C150 Type II or V
2.ASTM C595 Type IP(MS) or IP(HS)
3.ASTM C150 Type III. Type III shall have no more than 8 percent C3A.
4.ASTM C595 Type IL(MS), IL(HS), IT(MS), or (HS) Class 2 requires that the concrete have a maximum Water/Cementitious Material Ratio of 0.45 and one of the following:
1.ASTM C150 Type V with a minimum of a 20 percent substitution of Class F fly ash or slag cement by weight
2.ASTM C150 Type II or III or ASTM C595 Type IL with a minimum of a 20 percent substitution of Class F fly ash, High-Reactivity Pozzolan, or slag cement by weight. The Type II,III, or IL cement shall have no more than 0.040 percent expansion at 14 days when tested according to ASTM C452.
3.A blend of portland cement meeting ASTM C150 Type II or III with a minimum of 20 percent Class F fly ash, High - Reactivity Pozzolan, or slag cement by weight, where the blend has less than 0.05 percent expansion at 6 months or 0.10 percent expansion at 12 months when tested according to ASTM C1012
4.ASTM C595 Type IP(HS), IL(HS), or IT(HS). Class F fly ash, slag cement, or High-Reactivity Pozzolan may be substituted for Type IL(HS) cement.
5.ASTM C595 Type IL(MS) or IT(MS) plus Class F fly ash, slag cement, or High -Reactivity Pozzolan where the blend has less than 0.05 percent expansion at 6 months or 0.10 percent expansion at 12 months when tested according to ASTM C1012 Class 3 requires that the concrete have a maximum Water/Cementitious Material Ratio of 0.40 and one of the following:
1.A blend of portland cement meeting ASTM C150 Type II, III, or V or ASTM C595 Type IL(MS) with a minimum of a 20 percent substitution of Class F fly ash, High -Reactivity Pozzolan, or slag cement by weight, where the blend has less than 0.10 percent expansion at 18 months when tested according to ASTM C1012
2.ASTM C595 IT(MS) plus High -Reactivity Pozzolan where the blend has less than 0.10 percent expansion at 18 months when tested according to ASTM C1012
3.ASTM C595 Type IP(HS), IL(HS), or IT(HS) having less than 0.10 percent expansion at 18 months when tested according to ASTM C1012. Class F fly ash, slag cement, or High - Reactivity Pozzolan may be substituted for Type IL(HS) cement.
4.ASTM C150 Type I, II, III, or V or ASTM C595 Type IL(MS) plus a minimum of 20 percent Class F fly ash when the R factor of the fly ash is less than 0.75. R factor is determined using the following from the chemical composition of the fly ash: 601.05 601-8 3 25 OFeCaOR−= ASTM C150 Type III cement may only be used in Class P or PS Concrete when approved by the Engineer. Class C fly ash shall not be substituted for cement when Class 1, 2, or 3 sulfate resistance/exposure class is specified. The maximum Water/Cementitious Material Ratio may be exceeded when an expansive cement additive is used. When fly ash or high -reactivity pozzolan is used to enhance sulfate resistance, it shall be used in a proportion greater than or equal to the proportion tested per ASTM C1012, shall be the same source, and shall have a calcium oxide content no more than 2.0 percent greater than the fly ash or high- reactivity pozzolan tested according to ASTM C1012. ASTM C1012 test results are acceptable for up to two years from the completion date of the test. Table 601 -2 CONCRETE SULFATE EXPOSURE CLASS Water -Soluble Sulfate (SO 4) in Dry Soil, (%) Sulfate (SO 4) in Water, ppm Sulfate Exposure Class 0.00 to 0.10 0 to 150 Class 0 0.11 to 0.20 151 to 1,500 Class 1 0.21 to 2.00 1,501 to 10,000 Class 2 2.01 or greater 10,001 or greater Class 3 CONSTRUCTION REQUIREMENTS
601.05 Mix Design Submittal Requirements. The Contractor shall submit a Concrete mix
design for each class of concrete being placed on the project. Concrete shall not be placed on the project before the Concrete mix design has been approved by the Engineer. The Concrete mix design will be reviewed following the procedures of CP 62. The Concrete mix design will not be approved when the laboratory trial mix data or aggregate data are the results from tests performed more than two years in the past. The concrete mix design shall show the weights and s ources of all materials including cements, pozzolans, aggregates, fibers, pigments, water, additives , and the water to cementitious material ratio (w/cm). When determining the w/cm, the weight of cementitious material (cm) shall be the sum of the weights of the cement, slag cement, fly ash, silica fume, and high -reactivity pozzolan. Water from dosages of admixtures greater than 10 ounces per 100 pounds of cementitious materials shall be included in the calculation of w/cm. 601.05 601-9 The laboratory trial mix data shall include results of the following:
1.AASHTO T 119 (ASTM C143) Slump of Hydraulic Cement Concrete, except when the concrete is SCC.
2.AASHTO T 121 (ASTM C138) Weight per Cubic Foot, Yield, and Air Content (Gravimetric) of Concrete
3.AASHTO T 152 (ASTM C231) Air Content of Freshly Mixed Concrete by the Pressure Method
4.ASTM C39 Compressive Strength of Cylindrical Concrete Specimens shall be performed with at least two specimens at 7 days and three specimens at 28 days.
5.Class P concrete shall include AASHTO T97 (ASTM C78) Flexural Strength of Concrete (Using Simple Beam with Third -Point Loading). At least two specimens will be tested at 7 days and four specimens at 28 days. The lab trial mix shall produce a flexural stre ngth at 28 days of at least 650 psi.
6.Concrete with an OG shall indicate the gradation of the blended aggregates. Optimized gradations shall be developed by an approved mix design technique such as Tarantula Curve, Shilstone, or KU mix.
7.SCC concrete shall include ASTM C1611 Standard Test Method for Slump Flow of Self - Consolidating Concrete. Slump flow shall be measured using an inverted slump cone.
8.SCC concrete shall include ASTM C1621 Standard Test Method for Passing Ability of Self - Consolidating Concrete by J -Ring.
9.SCC concrete shall include ASTM C1610 Standard Test Method for Static Segregation of Self - Consolidating Concrete Using Column Technique.
10.When concrete is to be placed using a paver, the edge slump and surface voids shall be reported per CP 63. Before placement of accelerated Class P Concrete, the Contractor shall provide the Engineer a report of maturity relationships per CP 69. Except for Class PS concrete, the laboratory trial mix must produce an average compressive strength of at least the required field compressive strength specified in Table 601 -1. For Class PS concrete, the laboratory trial mix must produce an average compr essive strength of at least 115 percent of the required field compressive strength specified in Table 601 -1. When entrained air is specified in the Contract for Class BZ concrete, the trial mix shall be run with the required air content. The laboratory trial mix shall have a relative yield of 0.99 to 1.02. 601.05 601-10 Aggregate data shall include the results of the following:
1.AASHTO T 11 (ASTM C117) Materials Finer Than 75 um (No. 200) Sieve in Mineral Aggregates by Washing
2.AASHTO T 19 (ASTM C29) Unit Weight and Voids in Aggregate
3.AASHTO T 21 (ASTM C40) Organic Impurities in Fine Aggregate for Concrete
4.AASHTO T 27 (ASTM C136) Sieve Analysis of Fine and Coarse Aggregates
5.AASHTO T 84 (ASTM C128) Specific Gravity and Absorption of Fine Aggregate
6.AASHTO T 85 (ASTM C127) Specific Gravity and Absorption of Coarse Aggregate
7.AASHTO T 96 (ASTM C131) Resistance to Degradation of Small -Size Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine
8.AASHTO T 104 (ASTM C88) Soundness of Aggregate by Use of Sodium Sulfate or Magnesium Sulfate
9.CP 37 Plastic Fines in Graded Aggregates and Soils by use of the Sand Equivalent Test
10.ASTM C535 Resistance to Degradation of Large- Size Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine
11.ASTM C1260 Determining the Potential Alkali Reactivity of Aggregates (Accelerated Mortar -Bar Method). When an aggregate source is known to be reactive, ASTM C1567 results may be submitted in lieu of ASTM C1260 results. Aggregate tested by ASTM C1260 with an expansion of 0.10 percent or more, or that is known to be reactive, shall not be used unless mitigative measures are included in the mix design. Mitigative measures shall be tested using ASTM C1567 and exhibit an expansion less than 0.10 percent by one of the following methods:
1.Combined Aggregates. The mix design sources of aggregates, cement , and mitigative measures shall be tested. The proportions of aggregates, cement , and mitigative measures shall be those used in the mix design.
2.Individual Aggregates. Each source and size of individual aggregates shall be tested. The source of cement and mitigative measures shall be those used in the mix design. The highest level of mitigative measures for any individual aggregate shall be the min imum used in the mix design. For all concrete mix designs with ASTM C150 and ASTM C595 Type IL cements, the total substitution of cement shall not exceed 50 percent by weight of total cementitious material. For all concrete mix designs with ASTM C595 Type IP, IP(MS), IP(HS), or IT cements: fly ash or high -reactivity pozzolan shall not be substituted for cement. For all concrete mix designs with ASTM C595 IT cements, slag cement shall not be substituted for cement. 601.06 601-11 For all concrete mix designs with ASTM C595 Type IP, IP(MS), IP(HS) cements, when slag cement is substituted for cement, the total substitution of cement shall not exceed 50 percent by weight of total cementitious material. The Contractor shall submit a new Concrete Mix Design Report meeting the above requirements when a change occurs in the source, type, or proportions of cement, slag cement, fly ash, high - reactivity pozzolan, silica fume, or aggregate. Addition, removal, change of source, dosage change , or type of fibers to an approved mix design shall require a new mix design. Adjustments to aggregate weights may be made to adjust yield if the combined gradation remains constant (+/-1 percent) or within the optimized band. When a change occurs in the source or type of approved admixtures or the addition of approved accelerating, retarding , or hydration stabilizing admixtures to existing mix designs, the Contractor shall submit a letter stamped by the Concrete Mix Design Engineer approving the changes to the existing mix design. The change shall be approved by the Engineer before use. Unless otherwise permitted by the Engineer, the product of only one type of hydraulic cement from one source of any one brand shall be used in a concrete mix design. Approval of the concrete mix design by the Engineer does not constitute acceptance of the concrete. Acceptance will be based solely on the test results of concrete placed on the project. Once approved for a project, the mix design may be used for the duration of the project.
601.06 Batching . Measuring and batching of materials shall be done per AASHTO M 157 (ASTM
C94). The Contractor shall furnish a batch ticket (delivery ticket) with each load for all classes of concrete. Concrete delivered without a batch ticket containing complete information as specified shall be rejected. The Contractor shall collect and complete th e batch ticket at the placement site and deliver all batch tickets to the Engineer on a daily basis. The Engineer shall have access to the batch tickets at any time during the placement. The following information shall be provided on each batch ticket:
1.Supplier’s name and date
2.Truck number
3.CDOT Project number and location
4.Concrete class designation and item number
5.Cubic yards batched.
6.Time batched
7.CDOT mix design number.
8.Type, brand, and amount of each admixture and pigment
9.Type, brand, and amount of cement, slag cement, fly ash, and high -reactivity pozzolan.
10.Weights of fine and coarse aggregates or combined weight when an OG is pre- blended.
11.Moisture of fine and coarse aggregates or combined moisture when an OG is pre- blended.
12.Gallons (Pounds) of batch water (including ice)
13.Weight of polyolefin fiber reinforcement The Contractor shall add the following information to the batch ticket at the placement site: 601.06 601-12
14.Gallons of water added by the truck operator, the time the water was added, and the quantity of concrete in the truck each time water is added.
15.Number of revolutions of the drum at mixing speed (for truck mixed concrete)
16.Discharge time
17.Location of the batch in placement
18.Water to cementitious material ratio Electronic tickets are allowed as long as CDOT has access to the batch ticket and the batch ticket can be downloaded and saved by the Engineer in PDF format before placement, at any time during placement, and until the project is accepted.
a.Hydraulic Cement, Fly Ash, High- Reactivity Pozzolan, Slag Cement and Silica Fume. All cementitious material shall be measured by mass. Supplementary cementitious materials may be weighed cumulatively with cement. Cement and other cementitious material shall be weighed on a scale and in a weigh hopper, which is separate and distinct from those used for other materials. When the quantity of cementitious material exceeds 30 percent of the full capacity of the scale, the quantity of cement and the cumulative quantity of cement plus supplementary cementitious material shall be within plus or minus 1 percent of the required mass. For small batches to a minimum of 1 cubic yard, the quantity of cement and the quantity of cement plus supplementary cementitious material used shall not be less than the required amount or more than 4 percent in excess. A f raction of a bag of cement shall not be used unless weighed.
b.Water. Mixing water shall consist of water added to the batch, ice added to the batch, water occurring as surface moisture on the aggregates, and water introduced in the form of admixtures. The added water shall be measured by mass or volume to an accuracy of 1 percent of the required total mixing water. Added ice shall be measured by weight. In the case of truck mixers, wash water retained in the drum for use in the next batch of concrete shall be accurately measured or shall be discharged before loading t he next batch of concrete. Total water (including any wash water) shall be measured or weighed to an accuracy of plus or minus 3 percent.
c.Aggregates. Aggregates from different sources and of different gradings shall not be stockpiled together. Aggregate shall be handled from stockpiles or other sources to the batching plant in such a manner as to secure a uniform grading of the material. Aggregates that have become segregated, or mixed with earth or foreign material, shall not be used. All aggregates produced or handled by hydraulic methods, and washed aggregates, shall be stockpiled o r binned for draining at least 12 hours before being batched. Rail shipment requiring more than 12 hours will be accepted as adequate binning only if the car bodies permit free drainage. In case the aggregates contain high or non -uniform moisture content, storage or stockpile period in excess of 12 hours may be required. Aggregate shall be measured by mass. The quantity of aggregate used in any batch of concrete as indicated by the scale shall be within plus or minus 2 percent of the required mass when weighed in individual weigh batchers. In a cumulative aggregate weigh batcher, the cumulative mass after each successive weighing shall be within plus or 601.07 601-13 minus 1 percent of the required cumulative amount when the scale is used in excess of 30 percent of its capacity. For cumulative mass for less than 30 percent of scale capacity, the tolerance shall be plus or minus 0.3 percent of scale capacity or plus or minus 3 percent of the required cumulative mass, whichever is less.
d.Bins and Scales. The batching plant may include bins, weighing hoppers, and scales for the fine aggregate and for each size of coarse aggregate. A bin, hopper, and scale for cementitious material shall be included. A single weighing hopper with an accumulative scale will be permitted, provided a separate scale is used for weighing cementitious material. Scales shall meet the requirements of subsection 109.01.
601.07 Mixing. Mixing of materials shall be done per AASHTO M 157 (ASTM C94). Concrete shall
be mixed in stationary mixers, in a central mix plant, in truck mixers, or in self -contained mobile mixers. Mixing time shall be measured from the time all materials, except water, are in the drum. Admixtures listed in the mix design, or admixtures approved per subsection 601.04 and water may be added at the project.
a.Mixing General. C oncrete shall be deposited in place within 90 minutes after batching when concrete is delivered in truck mixers or agitating trucks, and within 60 minutes when delivered in non -agitating trucks. The 90- minute time limit for a mixer or agitating trucks may be extended to 120 minutes if:
1.No water is added after 90 minutes.
2.The concrete temperature before placement is less than 90 °F. The 90- minute time limit for a mixer or agitating trucks may be extended to 180 minutes if:
1.No water is added after 90 minutes.
2.The concrete temperature before placement is less than 90 °F.
3.The approved concrete mix contains an approved retarding admixture. The 90- minute time limit for a mixer or agitating trucks may be extended longer than 180 minutes if:
1.An Extended Set Control Admixture (ESCA) is added at the time of batching. Procedures and doses shall be per manufacturer’s recommendations. The ESCA shall be on the approved products list.
2.The concrete temperature before placement is less than 90 °F.
3.Each load of concrete shall be sampled and tested by the Contractor for air content according to CP 61. 601.07 601-14
4.The Department will cast three additional acceptance cylinders. If the acceptance cylinders tested at 28 days do not meet design strength, the additional cylinders will be tested at 56 days for acceptance.
b.Central -Mixed Concrete. Concrete that is mixed completely in a stationary mixer and transported to the point of delivery either in a truck agitator or a truck mixer operating at agitating speed, or in non- agitating equipment approved by the Engineer, shall conform to the followin g:
1.The mixing time shall be counted from the time all the solid materials are in the drum.
2.The batch shall be so charged into the mixer so that some water will enter in advance of the cement and aggregate.
3.All water shall be in the d rum by the end of the first one -fourth of the specified mixing time.
4.The volume of concrete mixed per batch may exceed the mixer's nominal capacity, as shown on the manufacturer’s standard rating plate on the mixer, by up to 10 percent provided concrete test data for strength, segregation, and uniform consistency are satisf actory, and provided spillage of concrete does not occur.
5.Where no mixer uniformity tests are made, the acceptable mixing time for mixers having capacities of 1 cubic yard or less shall be not less than 1 minute. For mixers of greater capacity, this minimum shall be increased 15 seconds for each cubic yard or fraction thereof of additional capacity. Uniformity testing shall be per AASHTO M157 (ASTM C94).
c.Truck Mixing . Truck mixed concrete shall conform with one of the following:
1.Concrete that is completely mixed in a truck mixer shall be mixed 70 to 100 revolutions at the mixing speed to produce uniform concrete. Concrete uniformity tests shall be made per AASHTO M157 (ASTM C94). Additional revolutions of the mixer beyond the number found to produce the required uniformity of concrete shall be at a designated agitating speed.
2.For concrete that is partially mixed in a stationary mixer, and then mixed completely in a truck mixer (shrink mixed concrete), the time of partial mixing shall be the minimum required to intermingle the materials . After transfer to a truck mixer, it shall be mixed at a speed to produce uniform concrete. Concrete uniformity tests shall be made per AASHTO M157 (ASTM C94). Additional revolutions of the mixer beyond the number found to produce the required uniformity of concrete shall be at a designated agitat ing speed.
3.Concrete mixed entirely in a stationary mixer and delivered to the job in a truck mixer shall be remixed for a minimum of 20 revolutions of the mixing drum at mixing speed at the job site before discharge. 601.07 601-15 When water is added at the delivery site to control the consistency of the concrete, the concrete shall be mixed for at least 30 revolutions of the mixer drum at mixing speed for each addition of water before discharge. These revolutions are in addition to the minimum revolutions required for mixing at the delivery site. The added water shall not cause the w/cm ratio to exceed the approved mix design w/cm ratio. Water from all sources shall be documented by the Contractor on the delivery slip for each load of concrete. The Contractor shall provide a Concrete Truck Mixer Certification. This certification shall show the various pick -up and throw -over configurations and wear marks so that the wear on the blades can be checked. Blades shall be replaced when any part or secti on is worn 1 inch or more below the original height of the manufacturer's design. A copy of the manufacturer's design, showing the dimensions and arrangement of blades, shall be available to the Engineer at all times. The Contractor shall furnish a water -measuring device in good working condition, mounted on each transit mix truck, for measuring the water added to the mix after the truck has left the charging plant. Each measuring device shall be equipped with an easy - to-read gauge. Water shall be measured to an accuracy of plus or minus 3 percent.
d.Self-Contained Mobile Mixer. Proportioning and mixing equipment shall be of the self - contained, mobile, continuous mixing type per ASTM C685 and subject to the following:
1.The mixer shall be self -propelled and capable of carrying sufficient unmixed dry, bulk cementitious materials, fine aggregate, coarse aggregate, admixtures, and water to produce on the site at least 6 cubic yards of concrete. The mixer shall have one bin f or each size aggregate.
2.The mixer shall be capable of positive measurement of cementitious materials being introduced into the mix. A recording meter visible at all times and equipped with a ticket printout shall indicate the quantity of total concrete mix.
3.The mixer shall provide positive control of the flow of water into the mixing chamber. Water flow shall be indicated by a flow meter and be readily adjustable to provide for minor variations in the aggregate moisture.
4.The mixer shall be capable of calibration to automatically proportion and blend all components of indicated composition on a continuous or intermittent basis as required by the finishing operation and shall discharge mixed material through a conventional chute directly in front of the finishing machine.
5.The Contractor shall perform calibration tests according to the equipment manufacturer's recommendations at the beginning of each project, and when there is a change in the mix design proportions or source of materials. The Engineer may require a calibration test or yield check when a change in the characteristics of the mixture is observed. The tolerances in proportioning the various material s shall be according to ASTM C685. 601.08 601-16
601.08 Air Content Adjustment. When a batch of concrete delivered to the project does
not conform to the minimum specified air content, an air -entraining admixture conforming to subsection 711.02 may be added per subsection 601.17. After the admixture is added, the concrete shall be re- mixed for a minimum of 20 revolutions of the mixer drum at mixing speed. The concrete shall then be re -tested by PC.
601.09 Forms.
a.Design. Forms shall be mortar tight and sufficiently rigid to prevent distortion due to the pressure of the concrete and other loads incidental to the concrete operations, including vibration. The rate of depositing concrete in forms shall be controlled to prevent deflections of the form panels in excess of the deflections permitted by these specifications. Forms for exposed concrete surfaces shall be designed and constructed so that the formed surface of the concrete does not undulate excessively in any direction between studs , joists, form stiffeners, form fasteners, or wales. Undulations exceeding 3/32 inch between the center -to-center distance of studs, joists, form stiffeners, form fasteners, or wales will be considered excessive . Should any form or forming system, even though previously approved for use, produce a concrete surface with excessive undulations, its use shall be discontinued until modifications satisfactory to the Engineer have been made. Portions of concrete structures with surface undulations in excess of the limits may be rejected by the Engineer. Forms for drainage inlets may be constructed of any suitable material that will produce a structure with the inside dimensions and at least the wall thicknesses shown on the plans. Undulations of finished interior wall surfaces shall not exceed 0.5 inch. Where called for in the Contract, the Contractor shall design and construct a permanent bridge deck forming system. Based on what is indicated, the Contractor will be permitted one of the following sets of options:
1.If the plans indicate that permanent deck forms are optional, the Contractor shall have the option of constructing a cast -in-place bridge deck u sing conventional forms, a full- depth cast -in-place bridge deck using permanent steel bridge deck forms, or a partial depth cast -in-place bridge deck using precast panel deck forms as a portion thereof.
2.If the plans indicate that permanent deck forms are required, the Contractor shall have the option of constructing a full depth cast- in-place bridge deck using permanent steel bridge deck forms, or a partial depth cast -in-place bridge deck using precast panel deck forms as a portion thereof.
3.If the plans indicate that precast panel deck forms are required, the Contractor shall construct a partial depth cast- in-place bridge deck using precast panel deck forms as a portion thereof. When SCC is used, forms shall be designed for loads as defined in American Concrete Institute (ACI) 347. Design calculations and form details shall be provided to the Engineer per Working Drawing requirements as defined in subsection 105.02. 601.09 601-17
b.Construction. Forms shall be constructed and maintained so as to prevent the opening of joints due to shrinkage of the lumber. The use of ties consisting of twisted wire loops to hold forms in position will not be permitted. Deck slab forms between girders shall be constructed with no allowance for settlement relative to the girders. The inside surfaces of forms shall be cleaned of all dirt, mortar , and foreign material. Forms that will later be removed shall be thoroughly coated with form oil before use. The form oil shall be a commercial quality form oil or other equivalent coating that will permit the ready release of the forms and will not discolor the concrete. Concrete shall not be deposited in the forms until all work connected with constructing the forms has been completed; all materials required to be embedded in the concrete have been placed, unless otherwise specified on the plans or approved; and the Engin eer has inspected said forms and material. Such work shall include the removal of all dirt, chips, sawdust, water , and other foreign material from the forms. Anchor devices may be cast into the concrete for later use in supporting forms or for lifting precast members. The use of driven types of anchorages for fastening forms or form supports to concrete will not be permitted. Backforms may be omitted with the approval of the Engineer in cases involving footings that can be placed in the dry wit hout the use of cribs or coffer dams. In such cases, the entire excavation shall be filled with concrete to the required elevation of the top of the footing. The additional concrete required shall be placed at the expense of the Contractor , except when footings are poured out to rock. Ex tra concrete required to pour footings out to rock will be allowed in the concrete quantities, provided t hat no allowance will be made for any concrete extending more than 6 inches in any direction beyond the neat lines of the footings as shown on the plans. Forms for the placement of deck concrete or other concrete work associated with structural steel girders shall be constructed so that any concentrated loads applied to girder webs shall be within 6 inches of a flange or stiffener. Where loads are applied to steel girder webs, they shall be applied in a manner that will not produce distortion to the web. For structural steel girders, temporary struts and ties shall be provided as necessary to resist lateral loads applied to the girder flanges and to prevent appreciable relative movement between the edge of deck form and the adjacent steel girder. When SCC is used, forms shall be constructed and maintained to meet aesthetic or smoothness criteria for the project. Form material other than plywood may be required.
c.Form Lumber . Form lumber for all exposed concrete surfaces shall be dressed at least on one side and two edges and shall be constructed so as to produce mortar -tight joints and smooth, even concrete surfaces. Forms shall be filleted and chamfered as shown on the plans and shall be given a bevel or draft in the case of all projections, such as girders and copings, to assure easy removal. Unless otherwise specified, forms for exposed surfaces shall be constructed with triangular fillets 3/4 inch by 3/4 inch at all exterior corners.
d.Metal Ties. Metal ties or anchorages within the forms shall be so constructed as to permit their removal to a depth of at least 1/2 inch from the face without injury to the concrete. When wire ties are used, the wires shall be cut back at least 1/4 inch from the face of the concrete upon removal of the forms. The cavities shall be filled with cement mortar and the surface left sound, smooth, even , and uniform in color. 601.09 601-18
e.Walls. Where the bottom of the forms is inaccessible, the lower form boards shall be left loose, or other provisions made so that extraneous material may be removed from the forms immediately before placing the concrete.
f.Surface Treatment. All forms shall be treated with oil before placing reinforcement except that an approved non -petroleum base form release agent shall be used for surfaces that are to receive stain or where petroleum based agents would be incompatible with the structural concrete coating . Wood forms shall be thoroughly moistened with water immediately before placing the concrete. For rail members or other members with exposed faces, the forms shall be treated with an approved form release agent to prevent the adherence of concrete. Material that will adhere to or discolor the concrete shall not be used. All concrete forms for surfaces that Structural Concrete Coating is to be appli ed shall be treated with a water -based concrete form release agent before placing reinforcement.
g.Metal Forms for General Use. The specifications for forms, regarding design, mortar tightness, filleted corners, beveled projections, bracing, alignment, removal, reuse , and oiling, apply to metal forms. The metal used for forms shall be of such thickness that the forms will remain true to shape. All bolt and rivet heads shall be countersunk. Clamps, pins or other connecting devices shall be designed to hold the forms rigidly together and to allow removal without injury to the concrete. Metal forms that do not present a smooth surfac e or do not line up properly shall not be used. Metal forms shall be free from rust, grease or other foreign matter. Permanent steel bridge deck forms shall be as described in subsection 601.10.
h.Removal of Forms. The forms for any portion of the structure shall not be removed until the concrete is strong enough to withstand damage when the forms are removed. Unless specified in the plans, forms shall remain in place for members that resist dead load bending until the concrete has reached a compressive strength of at least 80 percent of the required 28 -day strength, 0.80 f′
c.Forms for columns shall remain in place until the concrete has reached a compressive strength of at least 1,000 psi. Forms for sides of beams, walls, or other members that do not resist dead load bending shall remain in place until the concrete has reached a compressive strength of at least 500 psi. Forms and supports for cast -in-place concrete box culverts (CBCs) shall not be removed until the concrete compressive strength exceeds 0.6 f′c. for CBCs with spans up to and including 12 feet, and 0.67 f′c. for CBCs with spans exceeding 12 feet but not larger than 20 feet. Forms for CBCs with spans larger than 20 feet shall not be removed until after all concrete has been placed in all spans and has attained a compressive strength of at least 0.80f ′ c. Concrete compressive strength shall be determined by maturity meters per CP 69. At the Pre-pour Conference, the Contractor shall submit the location where maturity meters will be placed. The Contractor shall provide maturity meters and all necessary wires and connectors. The Contractor shall be responsible for the placement and maintenance of the maturity meter and wire. At a minimum, a maturity meter shall be placed at the mid -span of beams and at support locations. Placement shall be as directed by the Engineer. 601.09 601-19 For structures with multiple maturity meters, the lowest compressive strength shall determine when the forms can be removed. Acceptance cylinders shall not be used for determining compressive strength to remove forms. When field operations are controlled by maturity meters, the removal of forms, supports , and housing and the discontinuance of heating and curing may begin when the concrete is found to have the required compressive strength. Forms for the median barrier , railing, or curbs may be removed at the convenience of the Contractor after the concrete has hardened. All forms shall be removed except permanent steel bridge deck forms and forms used to support hollow abutments or hollow piers when no permanent access is available into the cells. When permanent access is provided into box girders, all interior forms, fal sework, and loose material shall be removed, and the inside of box girders shall be cleaned with an industrial vacuum. When ESCAs are used, the removal of forms, supports and housing, and the discontinuance of heating and curing may begin when the concrete is found to have the required compressive strength.
i.Patching. The mixed formula for patch mortar shall be determined by trial to obtain a good color match with the concrete when both patch and concrete are cured and dry.
j.Re-use of Forms . The shape, strength, rigidity, watertightness , and surface smoothness of reused forms shall be maintained at all times. Warped or bulged lumber shall not be used.
k.Precast Panel Deck Forms . Working drawings for precast panel deck forms shall be submitted to the Engineer in conformity with subsection 105.02. Prestressing for precast panel deck forms shall be per subsection 618.07(a). Concrete for precast panel deck forms shall be cured per subsection 618.12. Precast panel deck forms shall be stored and transported in a horizontal position and shall conform to the requirements of subsections 618.14(c) and 618.15. When precast panels are erected, the fit of mating surfaces shall have no more than a 1/8 - inch gap to prevent concrete leakage. If such fit cannot be provided, the joint shall be filled with grout or sealed with an acceptable caulking compound before the placing of the cast-in-place portion of the slab. Precast panels and their accessories, including components to set grade, shall not be attached by welding to steel girders or other structural steel elements or reinforcing steel. Welding, including arc strikes or grounding on any structural steel element , is prohibited. The Engineer will inspect all girder flanges for blemishes from arc strikes. All identified blemishes shall be repaired per AWS D1.5 Section 3.10. Repair of all blemishes shall be at the Contractor’s expense. Support angles or other steel components that will be left in place and exposed to the atmosphere in the final product shall be galvanized per subsection 509.11. 601.10 601-20
601.10 Permanent Steel Bridge Deck Forms .
a.General. Permanent steel bridge deck forms for concrete deck slab may be used as an alternate to removable forms pursuant to this specification and when specified on the plans. Permanent steel bridge deck forms shall not be used in the cantilever portions of the deck slab.
b.Materials . Permanent steel bridge deck forms and supports shall be fabricated from steel conforming to ASTM A653 (Grades A through E) having a galvanized coating designation of Z600 (G165) according to ASTM A653.
c.Design. The following criteria shall govern the design of permanent steel bridge deck forms:
1.The steel forms shall be designed on the basis of dead load of form, reinforcement , and plastic concrete plus 50 pounds per square foot for construction loads. The unit working stress in the steel sheet shall be not more than 0.725 of the specified minimum yield strength of the material furnished, but not to exceed 36,000 pounds per squa re inch. If permanent steel bridge deck forms are used, the depth of slab shown on the plans shall be provided above the forms. The weight of additional concrete to fill form flutes and the steel form dead load shall not exceed a total of five pounds per square foot from edge to edge of flanges in each bay and from front face to front face of abutments.
2.Deflection under the mass of the forms, the plastic concrete and reinforcement shall not exceed 1/180 of the form span or 1/2 inch whichever is less, but in no case shall the design loading be less than 120 psf total. The permissible form camber shall be based on the actual dead load condition. Camber shall not be used to compensate for deflection in excess of the foregoing limits.
3.The design span of the form sheets shall be the clear span of the form plus 2 inches measured parallel to the form flutes.
4.Physical design properties shall be computed per requirements of the American Iron and Steel Institute (AISI) Specification for the Design of Cold Formed Steel Structural Members, latest published edition.
5.All reinforcing steel shall have a minimum concrete cover of 1 inch.
6.Permanent steel bridge deck form shall not be used in panels where longitudinal deck construction joints are located between stringers.
7.Permanent steel bridge deck forms and their accessories shall not be attached by welding to steel girders or other structural steel bridge elements or reinforcing steel. Welding, including arc strikes or grounding, on any structural steel element , is prohibited. Blemishes, when found, shall be removed per AWS D1.5 Section 3.10. A determination that a blemish exists will be made by the Engineer and the repair shall be at the Contractor's expense.
8.The Contractor shall submit two sets of the fabricator's shop and erection drawings to the Engineer. The drawings shall be designed and electronically sealed by the Contractor's Engineer. The drawings will not be approved or returned to the Contractor. The drawings shall indicate the grade of steel, the physical and section properties of all permanent steel bridge deck form sheets, and attachment details. 601.11 601-21
d.Construction. All forms shall be installed per fabrication and erection plans submitted to the Engineer per subsection 601.10(c)8. Form sheets shall not be permitted to rest directly on the top of the girder flanges. Sheets shall be securely fastened to form supports and shall have a minimum bearing length of 1 inch at each end. Form supports shall be placed in direct contact with the girder flange. All attachments shall be made by bolts, clips , or other approved means. Welding will not be permitted to flanges. Permanently exposed form metal , where the galvanized coating has been damaged , shall be thoroughly cleaned, wire brushed and painted with two coats of zinc oxide -zinc dust primer, Federal Specification TT -P-641d, Type II, no color added, to the satisfaction of the Engineer. Minor heat discoloration in areas of welds need not be touc hed up. Transverse construction joints shall be located at the bottom of a flute and 1/4- inch weep holes shall be field drilled at not more than 12 inches on center along the line of the joint.
e.Placing of Concrete. Concrete shall be placed with proper vibration of the concrete to avoid honeycomb and voids, especially at construction joints, expansion joints, valleys, and ends of form sheets. Placement sequences, procedures, and mixes shall be approved by the Engineer. Calcium chloride or any other admixture containing chloride salts shall not be used in the concrete placed on permanent steel bridge deck forms. When SCC is used, vibration shall not be used to consolidate the concrete.
f.Inspection. If the Engineer determines that the procedures used during the placement of the concrete warrant inspection of the underside of the deck, the Contractor shall remove at least one section of the forms at a location and time selected by the Engineer for ea ch span. This will be done as soon after placing the concrete as practicable in order to provide visual evidence that the concrete mix and the Contractor’s procedures are obtaining the desired results. An additional section shall be removed if t he Engineer determines that there has been any change in the concrete mix or in the Contractor’s procedures warranting additional inspection. After the deck concrete has been in place for a minimum period of two days, the concrete shall be tested for soundness and bonding of the forms by sounding with a hammer as directed. If areas of doubtful soundness are disclosed by this procedure, the Contr actor shall remove the forms from such areas as ordered, for visual inspection. If corrective action is not required, the cost of form removal will be borne by the Department. If corrective action is required, the cost of form removal and corrective action shall be borne by the Contractor. The Contractor shall provide inspection platforms or other approved means of stationary support where the above visual inspection can be made.
601.11 Falsework .
a.General. The Contractor shall be responsible for designing and constructing falsework. The Contractor's Engineer shall determine whether falsework is necessary. When the Contractor's Engineer determines falsework is unnecessary, the Contractor shall submit a writt en statement signed by the Contractor's Engineer so stating. The Contractor’s Engineer shall prepare and electronically seal all falsework drawings including revisions, which shall meet the requirements of subsection 601.11. The Contractor shall stamp the drawings “Approved for Construction” and submit to the Engineer. The Engineer will not approve the drawings. 601.11 601-22
b.Certification. Before placement of any concrete supported by falsework, the Contractor’s Engineer shall certify that falsework materials and construction have been inspected and that all falsework design, materials, and construction conform to the requirements of the Contract and are safe for the placement of concrete. A copy of the certification on an acceptable form shall be submitted to the Engineer for record purposes.
c.Falsework Design.
1.The falsework design drawings shall show the stresses and deflections in all load supporting members and anticipated total settlement of falsework footings and joint take-up. Anticipated settlements shall not exceed 1 inch. The maximum deflection used in the design of the falsework shall be 1/270 of clear span, irrespective of the fact that the deflection may be compensated for by camber strips.
2.The design of falsework shall be based on the use of loads and conditions that are no less severe than those described in this section. The stresses listed are based upon the use of undamaged, high -quality materials and such stresses shall be reduced by the Contractor if lesser quality materials are to be used. The Contractor is responsible for the proper evaluation of the falsework materials and design of the falsework to safely carry the actual loads imposed.
3.The design load for falsework shall consist of the sum of dead and live vertical loads and an assumed horizontal load.
A.Dead loads shall include the weight of concrete, reinforcing steel, forms, and falsework. The weight of concrete and reinforcing steel shall be assumed to be at least 150 pounds per cubic foot for normal concrete and at least 120 pounds per cubic foot for lightweight concrete.
B.Timber dead load is 50 pounds per cubic foot. The dead load of timber forms may be assumed at 10 pounds per square foot for members smaller than 6 -inch x 6 inch. Dead load for steel and steel forms shall be 490 pounds per cubic foot. The weight of any other forming materials shall be specified on the drawings.
C.Live loads shall consist of the actual weight of any equipment to be supported by falsework applied as concentrated loads at the points of contact and a uniform load of at least 50 pounds per square foot applied over the area supported.
4.The assumed horizontal load to be resisted by the falsework bracing system shall be the sum of the actual horizontal loads due to equipment, construction sequence or other causes and an allowance for wind; however , the assumed horizontal load to be resiste d in any direction shall not be less than 2 percent of the total dead load for falsework up to 30 feet high, and four percent for falsework over 30 feet high. The falsework shall be designed so that it will have sufficient rigidity to resist the horizontal load before the placement of concrete.
5.The entire bridge superstructure cross -section, except railing, shall be considered to be placed at one time except as provided. Girder stems and connected bottom slabs, if placed more than five days before the top slab, may be considered to be self - supporting between falsework posts at the time the top slab is placed, provided that the distance between falsework posts does not exceed four times the depth of the portion of the girder placed in the first pour .
6.Falsework footings shall be designed to carry the load imposed upon them without exceeding the estimated soil bearing values and anticipated settlements. 601.11 601-23
7.Foundations for individual towers where the maximum leg load exceeds 30 kips shall be designed and constructed to provide uniform settlement under all legs of each tower under all loading conditions.
8.If the concrete is to be post -tensioned in the field, the falsework shall be designed to support all increased or readjusted loads caused by the prestressing forces, as shown on the plans.
9.The falsework design drawings shall include the following minimum information:
1.Type and grade of structural materials.
2.Allowable material stresses in bending, compression, and shear.
3.Modulus of elasticity, “E”.
4.Stress factors if used for short -term duration loading (timber only).
5.Summary of critical tower leg loads and locations on falsework drawings.
6.Weight of deck finishing machine and wheel or support spacing.
7.References for load data used for standardized falsework components.
8.Specification references for design criteria.
9.The bearing value of the soil as determined by the Contractor when footing type foundations are to be used.
10.Falsework design shall be based on the current edition of one of the following applicable specifications. However, it shall be based on AASHTO Specifications if highway traffic is to be supported. AASHTO American Association of State Highway and Transportation Officials, Load and Resistance Factor Design Bridge Design Specifications . AISC American Institute of Steel Construction, Manual of Steel Construction. ACI American Concrete Institute, Formwork for Concrete SP4 Building Code Requirements for Reinforced Concrete. NFPA National Forest Products Association, National Design Specifications for Stress Grade Lumber. AITC American Institute of Timber Construction Manual.
11.Manufactured Assemblies. Loading of jacks, brackets, columns, joists, and other manufactured devices shall not exceed the manufacturer's recommendations or 40 percent of the ultimate load -carrying capacity of the assembly based on the manufacturer's tests or additional tests as necessary. The maximum allowable dead load deflection of joists shall be limited to 1/500 of their spans. The Contractor shall furnish catalog or equivalent data showing the manufacturer's recommendations or perform tests, as necessary, to demonstrate the adequacy of any manufactured device proposed for use. The Contractor shall not substitute other manufacturer's components unless the manufacturer’s data encompasses such substitutions or field tests affirm the integrity of the system.
12.Connection details shall be so designed that structural shoring members are secure for all loading conditions. 601.11 601-24
d.Falsework Construction . The falsework shall be constructed per the falsework drawings. Suitable jacks, wedges, or camber strips shall be used to set the forms to the required grade or camber and to take up any settlement in the formwork either before or during the placing of concrete. Supports for deck slab forms sh all be constructed so as to prevent settlement relative to the girders. The amount of camber to be used to represent the behavior of the permanent structure is shown on the plans. Falsework and formwork for the placement of deck concrete or other concrete work associated with structural steel girders shall be constructed so that any concentrated loads applied to girder webs shall be within 6 inches of a flange or stiffener. Where l oads are applied to steel girder webs, they shall be applied in a manner that will not produce distortion to the web. For structural steel girders, temporary struts and ties shall be provided as necessary to resist lateral loads applied to the girders and to prevent movement between adjacent steel girders. Where the deck overhang exceeds 1/ 3 of the distance between steel girders, bracing shall be provided to prevent rotation of the exterior girder due to the weight of the overhang falsework and formwork and concrete placement operations. Struts and ties shall also be provided between interior steel g irders to prevent movement between girders. Falsework drawings for bracing, struts, and ties shall be submitted and conform to the requirements of subsection 601.11(a). The Contractor shall provide tell -tales attached to the forms and readable from the ground, in enough systematically placed locations, to determine the total settlement of the entire portion of the structure where concrete is being placed. Should unanticipated events occur, including settlements that deviate more than plus or minus 3/8 inch from those indicated on the falsework drawings, which in the opinion of the Engineer would prevent obtaining a structure conforming to the requirements of these specifications, the placing of concrete shall be discontinued until the corrective measur es satisfactory to the Engineer are provided. In the event satisfactory measures are not provided before the initial setting of the concrete in the affected ar ea, the placing of concrete shall be discontinued at a location determined by the Engineer. All unacceptable concrete shall be removed.
e.Falsework Removal . Unless specified in the plans or specifications, falsework shall remain in place until the concrete has attained a minimum compressive strength of 0.80f ′c. Falsework supporting any span of a simple span bridge shall not be released until after all concrete, excluding concrete above the bridge deck, has attained a compressive strength of at least 0.80 f′c. Falsework supporting any span of a continuous or rigid frame bridge shall not be released until after all concrete, excluding concrete above the bridge deck, has been placed in all spans and has attained the compressive strength of at least 0.80 f′c. Falsework for arch bridges shall be removed uniformly and gradually, beginning at the crown, to permit the arch to take its load slowly and evenly. Falsework supporting overhangs and deck slabs between girders shall not be released until the deck concrete has attained a compressive strength of at least 0.80 f′c. Falsework for pier caps that will support steel or precast concrete girders shall not be released until the concrete has attained a compressive strength of at least 0.80 f′c. Girders shall not be erected onto such pier caps until the concrete in the cap has attained the compressive strength of at least 0.80 f′c. 601.12 601-25 Falsework for cast -in-place prestressed portions of structures shall not be released until after the prestressing steel has been tensioned. Concrete compressive strength shall be determined by maturity meters per CP 69. At the Pre-Pour Conference, the Contractor shall submit the location that maturity meters will be placed. The Contractor shall provide maturity meters and all necessary wires and connectors. The Contractor shall be responsible for the placement and maintenance of the maturity meters and wires. At a minimum, a maturity meter shall be placed at the mid -span of beams and at support locations. Placement shall be as directed by the Engineer. For structures with multiple maturity meters, the lowest compressive strength shall determine when the falsework can be removed. Acceptance cylinders shall not be used for determining compressive strength to remove falsework.
601.12 Placing Concrete .
a.General. A Pre -placement Conference shall be held with the selected Contractor and Department personnel before the placement of concrete bridge decks to discuss the method and sequence of placing concrete. At the Pre -placement Conference, the Contractor shall present a concrete winter protection plan for acceptance by the Engineer. The accepted concrete winter protection plan shall contain information on the number and type of heat sources to be used, a ske tch detailing the enclosure materials, and all other pertinent information. Sufficient equipment shall be supplied to continuously maintain the specified temperature uniformly in all parts of the enclosure. Insulated blankets on top of the bridge deck an d freely circulated artificial heat below the deck will be permitted. Concrete shall not be placed until forms have been completed and materials required to be embedded in the concrete have been placed, and the Engineer has inspected the forms and materials. The forms shall be cleaned of all debris before concrete is placed. The external surface of all concrete shall be thoroughly worked during the placing by means of tools of an approved type. The working shall be such as to force all coarse aggregate from the surface and to bring mortar against the forms to produce a smooth finish substantially free from water and air pockets, or honeycomb. Water or finishing aids shall not be added to the surface of the concrete to assist in finishing operations. Hand finishing shall be minimized wherever possible. The hand finishing methods shall be addressed in the Process Control Plan for concrete finishing. Hand -finished concrete shall be struck off and screeded with a portable screed that is at least 2 feet longer than the maximum width of the surface to be struck off. It shall be sufficiently rigid to retain its shape. Concrete shall be thoroughly consolidated by hand vibrators. Hand finishing shall not be allowed after the concrete has been in place for mor e than 30 minutes or when the initial set has begun. Finishing tools made of aluminum shall not be used. The Contractor shall provide a Process Control Plan (PCP) to ensure that proper hand finishing is accomplished per current industry standards. It shall identify the Contractor’s method for ensuring that the provisions of the PCP are met. The PCP shall be submitted to 601.12 601-26 the Engineer at the Pre- construction Conference. Concrete placement shall not begin until the Engineer has approved the PCP . The PCP shall identify and address issues affecting the quality of finished concrete including but not limited to:
1.Timing of hand finishing operations.
2.Methodology to place and transport concrete.
3.Equipment and tools to be utilized.
4.Qualifications and training of finishers and supervisors. When the Engineer determines that any element of the approved PCP is not being implemented or that hand-finished concrete is unacceptable, work shall be suspended. The Contractor shall supply a written plan to address improperly placed mat erial and to remedy future hand -finishing failures and bring the work into compliance with the PCP . The Engineer will review the plan for acceptability before authorizing the resumption of operations.
b.Hot Weather Limitations . Placing of concrete during hot weather shall be limited by the temperature of the concrete at the time of placing. Mixed concrete that has a temperature of 90 ºF or higher, shall not be placed. The Contractor shall provide fogging equipment and keep the concrete surface moist at all times by fogging with an approved atomizing nozzle until the curing material is in place. The aggregate stockpiles shall be kept moist at all times.
c.Cold Weather Limitations . The mixed concrete temperature shall be between 50 and 90 ºF at the time of placement. Water , aggregates, or both shall be heated , when necessary , under such control and in sufficient quantities to avoid fluctuations in the temperature of the concrete of more than 10 ºF from batch to batch. To avoid the possibility of flash set when the water is heated to a temperature in excess of 100 ºF , the water and the aggregates shall be charged into the mixer before the cement is added. Heating equipment or methods that alter or prevent the entrainment of the required amount of air in the concrete shall not be used. The equipment shall be capable of heating the materials uniformly. Aggregates and water used for mixing shall not be heated to a temperature exceeding 150 ºF . Materials containing frost or lumps of frozen material shall not be used. Stockpiled aggregates may be heated by the use of dry heat or steam. Aggregates shall not be heated directly by gas or oil flame or on sheet metal over fire. When aggregates are heated in bins, steam -coil or water -coil heating, or other methods that will not be detrimental to the aggregates may be used. The use of live steam on or through binned aggregates will not be permitted. Concrete shall not be placed on frozen ground. Before concrete placement, all ice, snow, and frost shall be completely removed from within formwork. Salt shall not be used to thaw ice, snow, or frost. 601.12 601-27
d.Chutes and Troughs. Concrete shall be placed so as to avoid segregation of the materials and the displacement of the reinforcement. Concrete shall not be dropped more than 5 feet unless confined by closed chutes or pipes. Care shall be taken to fill each part of the form by depositing the concrete as close to the final position as possible. The coarse aggregate shall be worked back from the forms and worked around the reinforcement without displacing the bars. After the initial set of the concrete, the forms shall not be jarred, and strain shall not be placed on the ends of projecting reinforcement. Where steep slopes are required, the chutes shall be equipped with baffle boards or be in short lengths that reverse the direction of movement. The Contractor shall not use pipes, fittings, chutes, troughs, spouts, or tremies that are fabricated of aluminum materials for pumping, conveying, or placing concrete. Concrete shall not be pumped through aluminum alloy pipe . All chutes, troughs , and pipes shall be kept clean and free from coatings of hardened concrete.
e.Vibrating. Unless otherwise directed, the concrete shall be consolidated with suitable mechanical vibrators operating within the concrete. When required, vibrating shall be supplemented by hand spading with suitable tools to assure proper and adequate consolidation . Vibrators shall be of a type and design approved by the Engineer. They shall be capable of frequencies of at least 10,000 vibrations per minute, in air. Vibrators shall be so manipulated as to work the concrete thoroughly around the reinforcement and embedded fixtures and into corners and angles of the forms. Vibrators shall not be used as a means to cause concrete to flow or run into position in lieu of p lacing. The vibration at any point shall be of sufficient duration to accomplish consolidation but shall not be prolonged to the point where segregation occurs. When SCC is used, vibrators shall not be used to consolidate the concrete.
f.Depositing Concrete Under Water. Concrete, except for cofferdam seals, shall not be deposited under water , unless approved by the Engineer. If approved, care shall be exercised to prevent the formation of laitance. Concrete shall not be deposited until all laitance, which may have forme d on concrete previously placed, has been removed. Pumping shall be discontinued while depositing foundation concrete if it results in a flow of water inside the forms. Concrete deposited under water shall be carefully placed in a compact mass in its final position by means of a concrete pump and tremie. The discharge or bottom end of the tremie shall be lowered to contact the foundation at the start of the concrete placement and shall be raised during the placement at a rate that will ensure that the bottom or discharge end of the tremie is continuously embedded or buried in fresh concrete a minimum of 12 inches. Air and water shall be excluded from the tremie pipe by keeping the pipe continuously filled. The continuity of th e placement operation shall be maintained without breaking the seal between the concrete mass and the discharge end of the tremie until the lift is completed. The placed concrete shall not be disturbed after it has been deposited. 601.12 601-28
g.Placement. Concrete shall be placed in horizontal layers not more than 18 inches thick except as provided. When less than a complete layer is placed in one operation, it shall be terminated in a vertical bulkhead. Each layer shall be placed and consolidated before the preceding batch has taken an initial set. Each layer shall be so consolidated as to avoid the formation of a construction joint with a preceding layer that has not taken an initial set. Bridge deck concrete on superelevation or grade that exc eeds 2 percent shall be placed from the low point upward. When the placing of concrete is temporarily discontinued, the concrete, after becoming firm enough to retain its form, shall be cleaned of laitance and other objectionable material to a sufficient depth to expose sound concrete. The top surfaces of concrete adjacent to the forms shall be smoothed with a trowel to minimize visible jo ints upon exposed faces. Work shall not be halted within 18 inches of the top of any face, unless provision has been made for a coping less than 18 inches thick, in which case the construction joint may be made at the underside of the coping. Immediately after the work of placing concrete is halted, all accumulations of mortar splashed upon the reinforcement and surfaces of forms shall be removed before the concrete takes its initial set. Care shall be taken when cleaning reinforcing steel to prevent damage to or breakage of the concrete- steel bond. Where Class DT concrete is used for patching, repair , or topping of existing concrete, the area that the Concrete Class DT contacts shall be prepared by shot blasting 1/8 to 3/16 inch deep or rotomilling. If Class DT concrete is not placed within one week of the shot blasting or rotomilling the area shall then be sandblasted and cleaned of all sand, concrete fragments, dirt, and other foreign material within one week of placement. The area shall be moistened two to four hours before placement and shall be free of standing water at the time of placement. When concrete is placed by pumping, the pumping equipment shall be thoroughly cleaned before concrete placement. Excess form release agent shall be removed from the hopper. The pump shall be primed at the Contractor’s expense by pumping and discarding enough concrete to produce a uniform mix exiting the pump. At least 0.25 cubic yards of concrete shall be pumped and discarded to prime the pump. Water or admixtures shall not be added directly into the concrete pump hopper after placement has commenced. If wa ter or admixtures are added to the concrete pump hopper, all concrete in the concrete pump hopper and the line shall be discarded and the pump shall be re -primed at the Contractor’s expense. The pump operator shall have a valid operator’s certification from the American Concrete Pumping Association or approved equal. Boom pumps shall have a documented current inspection as required by American Society of Mechanical Engineers ( ASME ) B30.27. Equipment added to the pump shall meet the pump manufacturer’s specifications. The Contractor shall submit the specifications of the pumping equipment and the qualifications of the operator to the Engineer for review at least two weeks before pumping concre te. Equipment and operators rejected by the Engineer shall be replaced at the Contractor’s expense. The pump shall be operated so that a continuous stream of concrete is produced. The pump equipment shall use a minimum of one of the following to maintain concrete uniformity: 601.12 601-29
1.A 360 -degree loop immediately before the delivery end of the pump line.
2.A minimum one -inch reducer installed at the entry to the delivery hose.
3.A minimum one inch reducing delivery hose.
4.A cable attached to the pump boom creating a minimum 90 -degree bend in the steel braided flexible hose. The point of discharge from the flexible hose at the end of the boom shall be at or above the lowest point of the bend.
5.On horizontal pours, a 10-foot minimum horizontal delivery system placed on the deck.
6.Other approved methods. Metal pump lines or couplings shall not rest directly on epoxy -coated reinforcing steel . The point of discharge of the pump shall be as close to the bridge deck elevation as possible. When SCC is used, concrete should be placed in one layer for the full depth of the formwork. No maximum layer thickness applies.
h.Placing Sequence. Unless otherwise shown on plans, or ordered, the concrete placing sequence shall be as follows: Concrete in columns shall be placed in one continuous operation. The concrete in columns shall be allowed to set at least 12 hours before caps are placed. Each span of simple span concrete slab and girder bridges less than 30 feet in length shall be placed in one continuous operation. Concrete for simple or continuous girder spans greater than 30 feet shall be placed in two operations; the first operation shall consist of placing the girder stems and any slab at the bottom of the stems, and the second operation shall consist of placing the top deck slab. The second pour shall not be made until the first pour has reached a compressive strength of twice the d esign unit stress shown on the plans. Transverse construction joints shall be located as shown on the plans, or as approved. Concrete slabs on simple span steel girder bridges shall be poured in one continuous operation for each span. If approval is given to place the deck of the entire structure, the Contractor shall use an approved retarder, when necessary, to retain the workability of the concrete and to obtain the desired finish. Concrete slabs on continuous span steel girder bridges shall be placed per the placing sequence shown on the plans. The Contractor may place the deck of the entire structure in one operation when approved. An approved retarder shall be used, when necessary, to retain the workability of the concrete and to obtain the desired finish. The leading edge of the freshly placed concrete shall be kept parallel to the substructure so that the girders will be loaded evenly during the placing and screeding operation.
i.Drainage and Weep Holes. Drainage and weep holes shall be constructed at locations shown on the plans or as ordered. Ports or vents for equalizing hydrostatic pressure shall be placed below low water. Forms for weep holes shall consist of approved form material. Wooden forms shall be removed after the initial set of concrete has taken place. Inlets of weep holes shall be surrounded with 1 cubic foot of filter material in a burlap sack, securely tied. 601.12 601-30
j.Construction Joints. Construction joints shall be made only as located on the plans or shown in the placing schedule, unless otherwise approved. All construction joints shall be cleaned of surface laitance, curing compound, and other foreign materials before fresh concrete is placed against the surface of the joint. Abrasive blast methods shall be used to clean construction joints between concrete girders and adjoining deck slabs. When the optional construction joints shown on the plans are used, any additional reinforcing steel shall be furnished and placed by the Contractor at no expense to the Department. Surfaces where concrete is to be placed shall be thoroughly moistened with water immediately before placing concrete. When concrete is to be placed on or adjacent to hardened concrete surfaces, the surface shall be saturated surface dry. Saturated surface dry concrete has no water on its surface. The pores of the concrete beneath the surface are moist. Where construction joints are allowed on visible surfaces, chamfer strips attached to the forms or other approved methods shall be utilized to provide an even joint appearance. When the plans show new concrete to be joined to existing concrete by means of bar reinforcing dowels placed in holes drilled in the existing concrete, the diameter of the holes shall be the minimum needed to place nonshrink grout or epoxy grout and the dowel. Immediately before placing the dowels, the holes shall be cleaned of dust and other foreign material and sufficient grout placed in the holes so that there are no voids in the drilled holes after the dowels are inserted.
k.Float Finish on Horizontal Surfaces . All freshly placed concrete on horizontal surfaces shall be given a float finish except as otherwise provided in the plans. Bridge decks and bridge sidewalks shall be finished per subsection 601.15(e). A float finish shall be achieved by placing an excess of material in the form and removing or striking off the excess with a template, forcing the coarse aggregate below the mortar surface. Creation of concave surfaces shall be avoid ed. After the concrete has been struck off, the surface shall be thoroughly w orked and floated with a suitable floating tool. Before the finish has set, the surface cement film shall be removed with a fin e brush in order to have a fine- grained, smooth but sanded texture.
l.Loading Piers and Abutments. Superstructure dead loads shall not be applied until piers and abutments have attained a compressive strength of 0.80 f′c. Concrete compressive strength shall be determined by maturity meters per CP 69. The Contractor shall provide an as -constructed survey of the abutments and piers before girder erection. The Contractor shall submit to the Engineer a copy of the survey notes detailing the girder seat elevations, anchor bolt locations and projections, and span distances from centerline of bearing to centerline of bearing. The survey notes shall indicate all adjustments necessary for bearing device dimensions other than those shown on the plans. The Contractor shall submit details for all adjustments to the Engineer for approval.
m.Opening to Traffic. Concrete structures shall remain closed to traffic and shall not carry the Contractor's equipment, for 21 days after placement of the concrete deck is completed. The structure may be opened to traffic earlier if the concrete deck and all other concrete has attained the Field Compressive Strength given in Table 601 -1. Concrete com pressive strength shall be determined by maturity meters per CP 69. 601.13 601-31 In addition, for cast -in-place prestressed bridges, construction vehicles whose gross weight exceeds 2,000 pounds, shall not be allowed on any span until prestressing steel for that span has been tensioned.
n.Epoxy Bonder. An epoxy bonder meeting the requirements of subsection 712.10 shall be used where epoxy bonder is called for on the plans.
o.Backfilling Structures that Support Lateral Earth Pressure. Concrete compressive strengths shall reach f´c before backfilling operations can begin with heavy equipment, such as skid - steers or self -powered riding compactors. Concrete compressive strengths shall reach 0.80f ′c. before backfilling operations can begin with hand -operated equipment. Concrete compressive strength shall be determined by maturity meters per CP 69.
601.13 Curing Concrete Other Than Bridge Decks . When the ambient temperature is below
35 °F the Contractor shall maintain the concrete temperature above 50 °F during the curing period. It shall be the Contractor’s responsibility to determine the necessity for undertaking protective measures. The minimum curing period shall be determined by one of the following methods. The Engineer shall review for adequacy, the Contractor’s determination of the curing period.
1.The minimum curing period shall be 120 hours.
2.The minimum curing period shall be from the time the concrete has been placed until the concrete has met a compressive strength of 80 percent of the required field compressive strength. The Contractor shall develop a maturity relationship for the concrete mix design per CP 69. The Contractor shall provide the maturity meter and all necessary thermocouples, thermometers, wires and connectors. The Contractor shall place, protect and maintain the maturity meters and associated equipment. Locations where the m aturity meters are placed shall be protected in the same manner as the rest of the structure. Enclosures with artificial heat sources will be permitted. If enclosures are used the Contractor shall monitor the structural integrity of the enclosure. Artificial heat sources shall not be placed in such a manner as to endanger formwork or expose any area of concrete to drying due to excessive temperatures. At the end of the curing period, the protection shall remain in place until it can be removed without permitting the concrete temperature to fall more than 50 °F in a 24 -hour period. Sudden changes in concrete temperature shall be prevented. Immediately after placing fresh concrete, all concrete shall be cured by one of the following methods. The Engineer shall review for adequacy, the curing method proposed by the Contractor.
a.Water Method. All surfaces other than slabs shall be protected from the sun and the whole structure shall be kept wet throughout the curing period. Surfaces requiring a Class 2 finish may have the covering temporarily removed for finishing, but the covering must be restored as soon as possible. All concrete slabs shall be covered as soon as possible with suitable material so that concrete is kept thoroughly wet for at least five days. The concrete surface shall be kept moist at all times by fogging with an atomizing nozzle until the covering is placed. 601.14 601-32
b.Membrane Forming Curing Compound Method. Curing compound may be applied only to those surfaces that are to receive a Class I or Class 4 final finish. A volatile organic content (VOC) compliant curing compound conforming to ASTM C309, Type 2 shall be used on surfaces where curing compound is allowed, except that Type 1 curing compound shall be used on e xposed aggregate or colored concrete, or when directed by the Engineer. Curing compound shall not be used on construction joints. The rate of application of curing compound will be per the manufacturer’s recommendation but shall not be more than 300 square feet per gallon. All concrete cured by this method shall receive two applications of the curing compound. The first coat shall be applied immediately after stripping of forms and acceptance of the concrete finish. If t he surface is dry, the concrete shall be thoroughly wet with water and the curing compound applied just a s the surface film of water disappears. The second application shall be applied after the first application has set. During curing operations, all unsprayed surfaces shall be kept wet with water. The coating shall be protected against marring for a perio d of at least 10 days after application. Coating marred, or otherwise disturbed, shall be given an additional coating. Should the surface coating be subjected continuously to injury, the Engineer may require that water curing, as described in subsection 601.13(a) be applied at once. When using a curing compound, the compound shall be thoroughly mixed within an hour before use. If the use of a curing compound results in a streaked or blotchy appearance, its use shall be discontinued. Water curing, as described in subsection
601.13 (a), shall then be applied until the cause of the defective appearance is
corrected.
c.Form Method. Concrete shall be protected by forms during the curing period. Forms shall be kept moist, when necessary, during the curing period to e nsure the concrete surface remains wet.
d.Blanket Method. Electrically heated curing blankets or insulation blankets may be used in cold weather to maintain the specified curing temperature and to retain moisture in the concrete. Blankets shall be lapped at least 8 inches and shall be free of holes. Blankets shall be secured at laps and edges to prevent moisture from escaping.
e.The following procedures shall be followed if the temperature of the concrete structure falls below 32 °F before the concrete reaches 80 percent of the required field compressive strength:
1.The Contractor will take cores at locations designated by the Engineer.
2.The Engineer will take immediate possession of the cores and submit the cores to a petrographer for examination per ASTM C856.
3.All costs associated with coring, transmittal of cores, and petrographic examination shall be borne by the Contractor regardless of the outcome of the petrographic examination.
4.Concrete damaged by frost as determined by the petrographic examination shall be removed and replaced at the Contractor’s expense.
601.14 Finishing Hardened Concrete Surfaces.
a.General. Unless otherwise authorized, all formed surfaces shall be finished with Class 1 finish. Generally, for form- cured surfaces, this finish will be constructed immediately following curing. 601-33 Where curing compound is allowed by subsection 601.13(b), the Class I finish shall be applied immediately after the forms are removed and forms may be removed for only that portion of the work that can be finished in the remainder of a workday . The exposed concrete shall be kept damp during the finishing period and covered with the curing compound immediately following the completion of the finishing. Structural Concrete Coating shall be the final finish for all concrete surfaces designated on the plans and in these specifications.
b.Classes of Finish . The various classes of finish are described as follows:
1.Class 1, Ordinary Surface Finish. All fins and irregular projections shall be removed from all surfaces except those that are not to be exposed or are not to be waterproofed. On all surfaces, the cavities produced by form ties, honeycomb spots, broken corners or edges , and other defects shall be thoroughly cleaned, moistened with water , and carefully pointed and trued with a mortar consisting of cement and fine aggregate and the surface left sound, smooth, even, and uniform in color. Mortar used in pointing shall be not more than 30 minutes old. The mortar patches shall be cured as specified in subsection 601.13 or other approved methods. All construction and expansion joints in the completed work shall be left carefully tooled and free of all mortar and concrete. The joint filler shall be left exposed for its full length with clean and true edges.
2.Class 2, Rubbed Finish. After completion of Class 1 Ordinary Surface Finish, the rubbing of concrete shall be started as soon as its condition will permit. Immediately before starting this work the concrete shall be moistened with water. Sufficient time shall have elapsed before the wetting down to allow the mortar used in the pointing to thoroughly set. Surfaces to be finishe d shall be rubbed with a medium -coarse carborundum stone, using a small amount of mortar on its face. The mortar shall be composed of cement and fine sand mixed in the same proportions as the concrete being finished. Rubbing shall be continued until all form marks, projections, and irregularities have been removed, all voids filled, and a uniform surface has been obtained. The paste produced by this rubbing shall be left in place. After all concrete above the surface being treated has been cast; the final finish shall be obtained by rubbing with a fine carborundum stone and water. This rubbing shall be continued until the entire surface is of a smooth texture and uniform color. After the final rubbing is completed and the surface has dried, it shall be wiped with burlap to remove loose powder and shall be left free from all unsound patches, paste, powder , and objectionable marks .
3.Class 4, Sand Blasted Finish. The cured concrete surface shall be sand blasted with hard, sharp sand to produce an even , fine-grained , uniform surface in which the mortar has been cut away. An exposed aggregate finish will not be required. However, aggregate exposed incidental ly to achieving the specified surface will be acceptable.
4.Structural Concrete Coating. Unless otherwise shown on the plans, the coating shall be applied to all exposed concrete elements of the structure above the ground line, including the tops of all pier caps and abutment seats, and shall extend 1 foot below th e finished ground line. Bridge bearing devices, curb and barrier cover plates, fence, and steel bridge rail shall be masked or otherwise protected to prevent structural concrete coating from coming into contact with them. 601-34 The final color of the Structural Concrete Coating shall have the Engineer’s written approval before batching and application on the project. Approval of the final color of the coating will be determined by the Engineer as follows:
A.A 1-foot-by-1-foot sample of each color required by the plans shall be submitted to the Engineer. The sample coating shall be applied to surfaces similar in texture to the concrete surfaces where the coating will be applied on the project. The sample coating shall be applied by the same methods to be used in field application.
B.At least three weeks before beginning application of the Structural Concrete Coating, 100 square foot test panels shall be prepared for each color selected by the Engineer. The test panels shall be produced on the actual concrete surface where the final product will be placed, at a location designated by the Engineer where all the required color and texture combinations may be viewed adjacent to each other. The coatings shall be applied to the test panels by the same methods to be used in the final field application. The Engineer shall be allowed one week after application of the last test panel for review and approval. Concrete surfaces that the structural concrete coating will be applied shall be prepared as follows:
1.Following curing of the concrete per subsection 601.13, all projections and bulges shall be removed and the surface sandblasted. Sandblasting shall profile the concrete surface, remove all form release agents, and all other deleterious materials that would inhibit the bond of the Structural Concrete Coating. The profile of the sandblasted concrete surface shall be equivalent to Concrete Surface Profile Three (CSP 3) as defined in Technical Guideline N o.03732, “Selecting and Specifying Concrete Surface Preparation for Sealers, Coatings, and P olymer Overlays” by the International Concrete Repair Institute. The Contractor shall provide a CSP 3 chip for use on the project.
2.A mortar mix, proportioned by volume, consisting of one part portland cement, two to three parts sand (conforming to the requirements of ASTM C144), and an approved bonding agent shall be used to patch all holes produced by form ties, honeycombing, voids 1/2 inch or larger in any dimension, broken corners and edges, and other defects. The mortar mix shall include an approved bonding agent. The quantity and application procedure of the bonding agent shall be per the recommendations of the manufacturer of the bonding agent. Areas to be patched shall be moistened with water before the mortar is applied, and the patched area shall be float finished and left flush with the concrete surface without checking or cracking of patches. Patching shall be done when the ambient temperature is at least 40 °F . Holes deeper than 3/4 inch shall be filled in layers that do not exceed 3/4 inch in thickness.
3.Within 24 hours before applying Structural Concrete Coating, the concrete surface to be coated shall be cleaned by water blasting at a minimum pressure of 3,000 psi to remove dust, dirt, and other materials that would inhibit the bonding of the coating. If the surface is contaminated before application of the coating, it shall be recleaned as required before application of the coating. New concrete shall be at least 28 days old or as approved in writing by the coating manufacturer before the coating is applied. 601.15 601-35 The coating shall be applied at a rate that will provide a minimum dry film thickness of 10 to 12 mils without texturing agent. The coating shall be mixed by a mechanical mixer and applied by spraying. Workmanship shall be such that the final coated surfac e is colored and textured uniformly and presents a pleasing appearance. All areas determined by the Engineer to be insufficiently coated shall be recoated. The coating shall be applied only when the ambient temperature is between 40 °F and 90 °F and is anticipated to remain above 40 °F for a minimum of 24 hours. The surface to be coated shall be dry and free of frost.
601.15 Bridge Deck Placing, Consolidating and Finishing . The Contractor shall prepare a
written Process Control Plan (PCP) that defines the process control measures the Contractor will use to ensure the placing, consolidating, and finishing, curing , and weather protection of the bridge deck conforms to the Contract requirements. The Contractor may refer to the Structural Concrete Pre- pour Conference Agenda in the department’s Construction Manual for examples of items that should be included in the P CP . It shall also identify the Contractor’s method for ensuri ng that the provisions of the PCP are met. The Contractor shall submit the PCP to the Engineer for written approval before the Pre- pour Conference. A Pre -placement Conference shall be held at a time mutually agreed upon before the initial placement of bridge deck concrete . Representatives of the ready -mix producer and the Contractor shall meet with the Engineer to discuss the following topics: • Concrete Mix materials and Proportions (cement content, effect of admixtures, etc.). • Work Schedule. • Applicable Specifications and Special Notes. • Delivery Details. • Planned Construction Joint Locations. • Role of All Personnel. • Construction Details - surface preparation, finish, joint locations, etc. • Testing Requirements. • Acceptance Criteria . • Contingency Plans for Wind, Rain, Breakdown, etc. • Curing Details.
a.Surface Preparation . Tops of girders, precast deck panels, pier caps, and abutments that will come into contact with bridge deck concrete shall be heated to raise the temperature above 35 °F before concrete placement. The proposed preheating method is subject to approval by the Engineer.
b.Placing. Concrete shall be placed per the requirements of subsection 601.12 except for the following: Concrete shall be placed in such manner as to require as little handling as possible and at sufficient depth to provide adequate material for screeding and finishing operations. The concrete shall be discharged as near its final location as practicable. The pattern of placement shall be such that lateral flow will be minimized. Concrete shall be placed against the leading edge of fresh concrete where practicable. Transverse joints may be used when the Engineer determines that the work is not progressing in a satisfactory manner, or when required by a change in weather conditions. 601.15 601-36 The Engineer may approve transverse joint locations to accommodate phased overlay construction.
c.Consolidating. Consolidation shall conform to subsection 601.12(e) and to the following: The Contractor shall provide suitable mechanical vibrators to disperse the batch at the point of discharge and to densify the concrete within the forms. The bond of fresh concrete to concrete previously placed shall be achieved by vibrating the new concret e together with the old. Immersion vibrators shall operate at a speed of at least 10,000 vibrations per minute in air. Internal vibration may be used along the edges of forms and in areas of congested reinforcing. A combination of immersion vibration an d surface consolidation shall be used.
d.Finishing. Following consolidation, the concrete shall be struck off and finished by mechanical longitudinal floating, mechanical rolling, surface vibration, or a combination of any of these methods. Surface vibrators shall be of the low frequency, high -amplitude type, operating at a speed of 3 ,000 to 4, 500 vibrations per minute. A paver’s steel scraping straightedge or lute, 4 -inch maximum width, shall be the only hand tool permitted on deck surfaces, except for a minimum use of hand floats and edgers along the forms and in areas where machine finishing cannot be effectively used. Only minimum hand finishing will be permitted. If the surface of the deck slab becomes dry immediately following finishing operations, due to an excessive evaporation rate, it shall be covered with wet burlap or fogged with water covering the entire deck surface using pneumatic atomizing nozzles. The fog spray shall be just enough to retard surface evaporation and shall not change the water -cement ratio. During periods of excessive drying, a cover of wet burlap or plastic sheeting shall be maintained o n the slab at all times until final cure is placed. Monomolecular film coatings applied to the surface of the slab to retain moisture may be used provided they effectively retard surface evaporation and are adequately maintained until the final cure is pl aced. Surfaces of bridge decks and bridge approach slabs that will be the final riding surface shall be finished as follows:
1.Final Finish. For the final finish a seamless strip of plastic turf shall be dragged longitudinally over the full width of the bridge deck after a seamless strip of burlap or other approved fabric has been dragged longitudinally over the full width of bridge deck to produce a uniform surface of gritty texture. The drags shall be mounted on a bridge other than the bridge to be furnished for Department use. The dimensions of the drags shall be such that a strip of material at least 3 feet wide is in contact with the full width of pavement surface while each drag is used. The drags shall consist of sufficient material and be maintained in such a condition that the resultant surface finish is of uniform appearance and reasonably free from grooves over 1/16 inch in depth. Where more than one layer of burlap drag is required, the bottom layer shall be approximately 6 inches wider than the layer above. Drags shall be maintained clean and free from encrusted mortar. Drags that cannot be cleaned shall be discarded and new drags installed. 601.15 601-37
2.Texturing. When posted speeds are 40 mph or higher, the finish shall be a grooved finish conforming to the following: After the Engineer has accepted the finished surface, and after the concrete has cured for at least seven days, the bridge deck surface shall be textured by grooving with a mechanized saw (sawed grooves). Grooving shall be done before the application of the concrete sealer. Only multi -blade saw cutting equipment furnished with circular blades may be used. Single blade equipment may be authorized by the Engineer where multi- blade assemblies do not allow sawing a distance of one foot from obstructions. The grooving shall be rectangular and conform to the following: Depth: 1/8 inch ± 1/32 inch Width: 1/8 inch ± 1/32 inch Spacing: 3/4 inch ± 1/32 inch center to center Grooves shall be longitudinal and parallel to the centerline of the roadway. Overlapping of grooves by succeeding passes will not be permitted. The grooves shall terminate 1.5 feet from the face of the curb or bridge rail on each side of the overlaid bridge deck.
3.Grooving To Bridge Joint System. For joint systems that are perpendicular to the roadway centerline, grooving shall extend to 9 inches plus or minus 3 inches from the armor of the joint. For the joint systems that are not perpendicular to the centerline of the roadway, grooving shall remain parallel to the centerline and shall not be nearer than 6 inches to the joint armor nor farther than 4 feet from the joint armor. The distance between grooves, from one side to the other of the joint system, shall not exceed 5 feet. The Contractor shall maintain the grooving equipment so that aggregate particles or cement build-up on the saws is promptly cleared or cleaned so that the grooves are neat, true , and in conformance with the specified dimensions.
e.Surface Smoothness – All Bridge Deck Surfaces. Acceptability of the deck surface will be determined as follows: The Contractor shall furnish a 10 -foot straightedge or other approved device. When the concrete is sufficiently hard, the Contractor shall test the bridge deck surface with the 10 -foot str aightedge or other approved device. Areas showing high spots of more than 1/8 inch but not exceeding 1/2 inch in 10 feet shall be marked. The marked area shall be immediately ground with an approved grinding tool so that the surface deviation will not be in excess of 1/8 inch in 10 feet. Grinding shall not reduce the concrete cover on reinforcing steel to less than 1 3/4 inches , (2 3/4 inches for bare decks without an overlay). Decks that require additional corrective action shall be corrected with a concrete overlay approved by the Engineer.
f.Movable Bridges. Movable bridges or platforms shall be provided by the Contractor and moved as directed to allow the inspectors to work over the freshly placed plastic concrete. A movable bridge shall be kept as close to the finishing screed as practical. The deck of t he movable bridges shall be a minimum of 24 inches wide and no more than 24 inches above the surface of the concrete and shall be capable of supporting two people. The Contractor shall provide additional movable bridges as appropriate for the work. 601.16 601-38
g.Concrete Bridge Sidewalks. Bridge sidewalks shall receive a final transverse broom finish.
h.Crack Repair. If cracks in the deck concrete with a width of 0.035 inches or greater occur within two weeks of placement, those cracks shall be repaired at the Contractor's expense. Cracks will be measured by the Engineer by insertion of a wire gauge at any time and temperature within the two weeks. The repair shall consist of filling the cracks with low viscosity, two -part, methacrylate , or an approved equal. The repair shall be per the recommendations of the manufacturer of the crack filling material.
601.16 Curing Concrete Bridge Decks .
The minimum curing period shall be 120 hours. The concrete surface shall be kept moist at all times by fogging with an approved atomizing nozzle or applying a monomolecular film coating to retard evaporation until the curing material is in place. Concrete bridge decks, including bridge curbs and bridge sidewalks, shall be cured as follows:
a.Decks placed from May 1 to September 30 shall be cured by the membrane- forming curing compound method followed by the water cure method as follows:
1.Membrane Forming Curing Compound Method. A volatile organic content (VOC) compliant curing compound conforming to ASTM C309, Type 2 shall be uniformly applied to the surface of the deck, curbs, and sidewalks at the rate of 1 gallon per 100 square feet. The curing compound shall be appl ied as a fine spray using power - operated spraying equipment . The power -operated spraying equipment shall be equipped with an operational pressure gauge and a means of controlling the pressure. Before and during application the curing compound shall be kept thoroughly mixed by recirculation or a tank agitator. The application shall be within 20 feet of the deck finishing operation. When the finish ing operation is discontinued, all finished concrete shall be coated with curing compound within 1/ 2 hour. The curing compound shall be thoroughly mixed within one hour before use.
2.Water Cure Method. The water cure method shall be applied as soon as it can be without marring the surface. The surface of the concrete, including bridge curbs and bridge sidewalks, shall be entirely covered with wet burlap and polyethylene sheeting. Before being placed, the burlap shall be thoroughly saturated with water. The wet burlap and polyethylene sheeting shall extend at least twice the thickness of the bridge deck beyond the edges of the slab and shall be weighted to remain in contact with the surface. The wet burlap and polyethylene sheeting shall remain in contact and be kept wet for the entire curing period.
b.Decks placed between November 1 and March 31 shall be cured by application of a membrane -forming curing compound followed by the blanket method as follows:
1.Membrane Forming Curing Compound Method. This method shall be applied per subsection 601.16(a)1. 601.16 601-39
2.Blanket Method. Curing blankets with a minimum R -Value of 0.5 shall be placed on the deck as soon as they can be without marring the surface. Blankets shall be loosely laid (not stretched) and adjacent edges suitably overlapped with continuous weights al ong the lapped joints. The blankets shall remain in place for a minimum of five days after placement.
c.Decks placed in April or October may be cured per either subsection 601.16(a) or 601.16(b).
d.For decks above an elevation of 8,000 feet above mean sea level, the Engineer may modify the time of year requirements for the cure methods defined in subsection 601.16(a) and 601.16(b).
e.When the ambient temperature is expected to fall below 40 °F during the curing period, the Contractor shall maintain the internal concrete temperature above 50 °F during the curing period and until the concrete has developed a compressive strength of 0.80f ’c. The Contractor shall provide suitable measures such as straw, additional burlap, ground heaters, or other suitable blanketing materials, and/or housing and artificial heat to maintain the internal concrete temperature above 50 ºF. Concrete shall not be placed on forms, girders, or deck panels that have a surface temperature less than 35 °F. Forms, girders, or deck panels where concrete is to be placed shall be free of snow, ice, and frost. Salt shall not be used to thaw ice, snow, o r frost. Heating forms, girders, or deck panels prior to concrete placement may be required. When the Contractor chooses to use an enclosure, the Contractor shall enclose the area underneath the deck and heat it so that the temperature of the enclosed air is as close as possible to the temperature of the enclosed air above the concrete. When artif icial heating is used to maintain the concrete temperature, adequate ventilation shall be provided to limit exposure to carbon dioxide, and the enclosed air temperature shall not exceed 90 ºF. During the curing period, the Contractor shall monitor the air temperature within the enclosure at intervals acceptable to the Engineer. The Contractor shall monitor and maintain the structural integrity of the enclosure. Heating of the enclosure may be stopped after 72 hours if the air achieved 0.80f’c. For every day that the internal temperature of the concrete is below 50 ºF during the curing period, an additional day of curing with a minimum internal concrete temperature of 50 ºF will be required unless the concrete has achieved 0.80f’c. After completion of the req uired curing period, the Contractor shall remove the enclosure in such a manner that the temperature of the concrete during the following 24 hours does not fall by more than 25 °F. When the Contractor chooses not to use an enclosure, after the curing period and after the concrete has achieved 0.80f’c, the Contractor shall remove the protection in such a manner that the temperature of the concrete during the following 24 hours does no t fall by more than 25 °F. For every day that the internal temperature of the concrete is below 50 ºF during the curing period, an additional day of curing with a minimum internal concrete temperature of 50 ºF will be required unless the concrete has achieved 0.80f’c. Internal concrete temperature shall be determined by using thermocouples. Thermocouple wire, connectors, and handheld thermometer shall be supplied by the Contractor. The Contractor shall install the thermocouples at locations designated by the Engineer. 601.17 601-40 Concrete compressive strength shall be determined by maturity meters. The Contractor shall develop maturity relationships for each mix placed during the cold weather conditions in accordance with CP 69. The maturity relationship shall be submitted to the Engineer prior to cold weather concrete placement. The Contractor shall provide the maturity meters and all necessary wires and connectors. The Contractor shall be responsible for the placement, protection, and maintenance of the maturity meters and wires. Locations where the maturity meters are placed shall be protected in the same manner as the rest of the concrete. Heat sources shall not be placed in such a manner as to endanger formwork or expose any area of concrete to drying due to excessive temperatures. If the internal concrete temperature at any location in the bridge deck concrete falls below 32 °F during the first 24 hours of the curing period, the Engineer may direct the Contractor to core the areas in question at the locations indicated by the Engineer. The Engineer will take immediate possession of the cores. The Engineer will submit the cores to a petrographer for examination in accordance with ASTM C856. Concrete damaged by frost, as determined by the petrographer, shall be removed and replaced at the Contractor's expense. All costs associated with coring, transmittal of cores, a petrographic examination shall be borne by the Contractor regardless of the outcome of the petrographic examination.
601.17 Acceptance and Pay Factors . These provisions apply to all concrete. The Contractor
shall sample concrete for both Process Control (PC) and Owner Acceptance (OA) per CP 61. The Engineer will witness the sampling and take possession of the OA samples at a mutually agreed upon location. The Contractor shall be responsible for Process Control (PC) testing for concrete. PC testing shall be performed at least once per day and then once per 50 cubic yards for concrete slump, unit weight, and concrete temperature. If the produced concrete does not have a relative yield of 0.99 to 1.02 for two consecutive yield determinations, concrete production shall cease, and the Contractor shall present a plan to correct the relative yield to the Engineer. When SCC is used, the Contractor shall test the first load of SCC before placement for Slump Flow (ASTM C1611) and Blocking Assessment (ASTM C1621). The Contractor shall take a sample from the first portion of the load and complete the slump flow and blocking assessment before depositing any portion of the load. The tests shall not be performed more than 15 minutes before placement. The slump flow shall be 20 to 26 inches. The blocking assessment shall be less than or equal to 2.0 inches. The Contractor will be allowed to make adjustments to the load with admixtures. After adjustments have been made, the slump flow and blocking assessment shall be retested. Each subsequent load of SCC shall be tested for Slump Flow. If the slump flow differs from the first load by more than 2.0 inches, the load shall be adjusted to have a slump flow within 2.0 inches of the first load, or the load may be tested for Blocking Assessment (ASTM C1621). If the load is tested for and meets the requirements for Blocking Assessment ( ASTM C1621), the load’s slump flow will be used for the acceptance of the following loads. When concrete placement is halted for more than 15 minutes, the slump flow and blocking assessment shall be retested before resuming placement. When the slump flow exceeds 26 inches, the concrete may be placed if the depth of penetration is less than 11 millimeters when tested using ASTM C1712 Test Method for Static Segregation Resistance of Self -Consolidating Concrete. If a load of concrete has a 601.17 601-41 slump flow greater than 26 inches and a depth of penetration less than 11 millimeters, the next load shall be tested for slump flow and blocking assessment to establish a new slump flow target. When SCC is used, subsection 601.17(b) does not apply. When SCC is used, the test methods for fabricating specimens per subsections 601.17(a) and 601.17(c) acceptance shall be modified to use ASTM C1758, Practice for Fabricating Test Specimens with SCC, for filling the test specimens with concrete.
a.Air Content. The first three batches at the beginning of each day’s production shall be tested by the Contractor’s PC and CDOT’s OA for air content. When the PC and OA air content measurements differ by more than 0.5 percent, both the PC and OA air meters shall be checked per ASTM C231. When air content is below the specified limit, it may be adjusted per subsection 601.08. Successive batches shall be tested by the Contractor’s PC and witnessed by the Engineer until three consecutive batches are within specified limits. After the first three batches, CDOT will follow the random minimum testing schedule. After the first three batches, the Contractor shall perform PC testing at a frequency of one random sample per 50 cubic yards. Air content shall not be adjusted after a CDOT OA test. At any time during the placement of the concrete, when an OA test on a batch deviates from the minimum or maximum percent of total air content specified, the batch that deviates from the specified air content by 1 percent or less may be accepted at a reduced -price using Table 601- 3. Portions of loads incorporated into structures before determining test results that indicate rejection as the correct course of action shall be subject to acceptance at reduced price, no payment, or removal as determined by the Engineer.
b.Slump . Except for Class BZ concrete, the slump of the delivered concrete shall be the slump of the approved concrete mix design plus or minus 2.0 inches. The maximum slump shall be 9.0 inches. Slump acceptance, but not rejection, may be visually determined by the Engineer. Any batch that exceeds the slump of the approved concrete mix design by more than 2.0 inches will be retested. If the mix design slump is exceeded by more than 2.0 inches a second time, that load will be rejected. If the slump is greater than 2 inches lower than the approved concrete mix design, the load may be adjusted by adding a water reducer or by adding water (if the w/cm allows) and retested. Portions of loads incorporated into structures before determining test results that indicate rejection as the correct course of action shall be subject to reduced payment or removal as determined by the Engineer.
c.Strength (When Specified). The concrete will be considered acceptable when the running average of three consecutive strength tests per mix design for an individual structure is equal to or greater than the specified strength and no single test falls below the specified strength by more than 500 psi. A test is defined as the average strength of three test cylinders cast in plastic molds from a single sample of concrete and cured under standard laboratory conditions before testing. If the compressive strength of any one test cylinder differs from the average by more than 10 percent, that compressive strength will be deleted and the average strength will be determined using the compressive strength of the remaining two test cylinders. 601.17 601-42 When the average of three consecutive strength tests is below the specified strength, the individual low tests will be used to determine the pay factor per Table 601- 3. If less than three strength tests are available the individual low tests, if any, will be used to determine the pay factor per Table 601 -3. The pay factor will be applied to the quantity of concrete represented by the individual low test. For concrete having a specified strength of less than 4 ,500 psi, when the compressive strength test is b elow the specified strength by more than 500 psi, the concrete represented will be rejected. For concrete having a specified strength of 4 ,500 psi or greater, when the compressive strength test is below the specified strength by more than 500 psi but not more than 1 ,000 psi, the concrete represented will be evaluated by the Department for removal, corrective action, or acceptance at a reduced price. All costs of the evaluation shall be at the Contractor's expense. When the compressive strength test is below the specified strength by more than 1 ,000 psi, the concrete represented will be rejected. The Contractor may take cores at its own expense and per Colorado Procedure 65 within 10 working days of being notified of a price reduction or up to 45 days after placement, whichever is later, to provide an alternative determination of strength. Price reduction for strength will be based on the 28 -day compres sive strength of acceptance cylinders or corresponding cores strength, whichever is greater. If the core compressive strength is at least 90 percent of the specified field compressive strength, the co ncrete represented by the cores will be accepted with no price reduction. The Engineer may use cores to determine acceptance or rejection of a part of the structure instead of acceptance cylinders. The Engineer will notify the Contractor in writing that CDOT will core the structure. The location of the coring will be directed by the Engineer. Coring and testing will be performed at the expense of the Department regardless of the result. Cores will be taken and tested per AASHTO T24 between 28 days and 45 days after concrete placement. Cores will be a minimum of 4 inches in diamet er unless otherwise approved by the Engineer. A minimum of three cores in a two -square - foot area will be obtained for locations of the structure that are suspect. If the compressive strength of any one core differs from the average by more than 10 percent, that compressive strength will be deleted and the average strength will be determined using the compressive strength of the remaining two cores. If the compressive strength of more than one core differs from the average by more than 10 percent, the averag e strength will be determined using all three compressive strengths of the cores. If the average core compressive strength is greater than or equal to 85 percent of the specified 28-day compressive strength, the concrete represented by the cores will be ac cepted. If the average core compressive strength is less than 85 percent of the specified 28 -day compressive strength, the structure will be evaluated by the Department according to subsection 105.03 for removal and replacement. Pay factors will not be based on co res taken by the Engineer. If the concrete represented by the cores is accepted, all costs associated with the repair of the core holes, including preparation and submittal of the repair method, will be measured and paid for separately. 601.17 601-43 After the Department performs additional core testing as described above, the Contractor may make one request that the structure be cored by the Contractor, tested and re - evaluated by the Department within 45 days after concrete placement. Coring and testing costs will be at the expense of the Contractor regardless of the result. Cores shall be taken at the same area of the structure as those obtained by the Engineer. The Engineer will approve the location of the cores before the Contractor coring the struc ture. All costs associated with the repair of these core holes including preparation and submittal of the repair method, will not be measured and paid for separately but shall be included in the work. If the concrete in the structure is found to be sufficient resulting time delays will be considered excusable. If the concrete in the structure is still found to be deficient, resulting time delays will be considered nonexcusable for this evaluation. Compensation for time delays will be evaluated by the Engineer per subsection 108.08. The Contractor shall submit a proposed repair method for the core holes for approval before coring. The method shall use an approved nonshrink concrete patching material with a minimum compressive strength of 4 ,500 psi. The Contractor shall submit the manufacturer’s recommendations along with the repair method. The Engineer will review and approve the proposed methodology before patching. The Engineer will distribute electronically to the concrete supplier all compressive strength Owner Acceptance (OA) data for the concrete supplied to the project. The Engineer will distribute the OA compressive strength data within two business days of th e 7-day and 28 - day compressive strength testing. The data will include the compressive strength and batch ticket number at a minimum. The Contractor shall not have a valid dispute or claim as a result of any action or inaction by the Department related t o the distribution of test results.
d.Pay Factors. The pay factor for concrete that is allowed to remain in place at a reduced price shall be determined according to Table 601 -3 and shall be applied to the unit price bid for the Item. If deviations occur in air content and strength within the same batch, the pay factor for the batch shall be the product of the individual pay factors. 601.17 601-44 Table 601 -3 PAY FACTORS FOR DEVIATIONS ON CONCRETE AIR CONTENT AND STRENGTH Below Specified Strength (psi) [ ≥ 4500 psi Concrete] *Pay Factor (Percent) 1 – 100 98 101 – 200 96 201 – 300 92 301 – 400 84 401 – 500 75 Reject 501 – 600 65 601 – 700 54 701 – 800 42 801 – 900 29 901 – 1000 15 Over 1000 Reject Below Specified Strength (psi) [ < 4500 psi Concrete] *Pay Factor (Percent) 1 – 100 98 101 – 200 96 201 – 300 92 301 – 400 84 401 – 500 75 Over 500 Reject Deviations From Specified Air (Percent) *Pay Factor (Percent) 0.0 – 0.2 98 0.3 – 0.4 96 0.5 – 0.6 92 0.7 – 0.8 84 0.9 – 1.0 75 Over 1.0 Reject Table 601 -3 Notes: * Concrete represented by out -of-spec tests will only be priced reduced with the lowest pay factor, not for each pay factor.
e.Bonding of Bridge Deck Overlay. After the curing period for Class DT concrete has elapsed, the overlay shall be “sounded” by the Contractor per ASTM D4580 Standard Practice for Measuring Delamination in Concrete Bridge Decks by Sounding to determine if the Class DT concrete has bonded to the bridge deck. In areas where the Class DT concrete has not bonded to the bridge deck, it shall be removed and replaced at the Contractor’s expense.
f.Maturity Meter Strength. When maturity meters are specified for determining strength for removing forms, removing falsework, backfilling against structures, or loading the structure, the Contractor shall provide the Engineer a report of maturity relationships per CP 69 before placement of concrete. If a maturity meter fails, is tampered with, destroyed, or was not placed, the following shall apply: The minimum curing time or waiting time for removing forms, removing falsework, backfilling against structures, or loading the structure shall be 28 days. The Contractor may choose at his own expense to core the structure represented by the maturity meter. Cores shall be obtained and tested according to CP 65. Cores shall be a minimum of 4 inches in diameter. A minimum of three cores in a two -square -foot area shall be obtained. If the compressive strength of any one core differs from the average by more than 10 percent, that compressive strength will be deleted and the average strength will be determined using the compressive strength of the remaining two cor es. If the compressive strength of more than one core differs from the average by more than 601.19 601-45 10 percent, the average strength will be determined using all three compressive strengths of the cores. The average compressive strength of the cores shall achieve the specified compressive strength of the structure. A structure may be cored only once.
g.Water to Cementitious Material Content (w/cm) Ratio. The maximum w/cm ratio is the ratio that was used in the laboratory trial mix for the Concrete mix design. The w/cm ratio shall be determined for each batch of concrete by the Contractor and provided to the Engineer for approval before placement. If an adjustment to the mix is made after the Engineer’s approval, the w/cm ratio shall be determined and submitted to the Engineer before the continuation of placement. Concrete that is placed without the Engineer’s approval shall be removed and replaced at the Contractor’s expense.
601.18 Unless otherwise stated in the plans or specifications, tolerances for concrete
construction and materials shall be per ACI 117. Cast in place bridge decks and bridge slabs shall be no more than 1/ 2 inch thicker nor more than 1/4 inch thinner than the cross -sectional vertical dimension shown on the plans. METHOD OF MEASUREMENT
601.19 Concrete will be measured by the cubic yard per the dimensions shown on the plans.
Plan quantities reflect deductions for all voids designed into the structure except, deductions will not be made for the volume occupied by pipes or conduits less than 3 inches in diameter, ducts for prestressing steel, reinforcing steel, anchors, weep holes, piling, and form liner textures and nominal chamfers. Concrete of the various classes will not be remeasured but will be the quantities shown on the plans. Exceptions for each class for each structure will be:
1.when field changes are ordered, or
2.when it is determined that there are discrepancies on the plans in an amount plus or minus 2 percent of the plan quantity for the structure. Bridge concrete shall consist of structural concrete, of the designated class, required for bridge construction shown on the plans, completed and accepted. Box culvert concrete shall consist of structural concrete, of the designated class, required for concrete box culvert construction including wingwalls, shown on the plans, completed and accepted. Wall concrete shall consist of reinforced structural concrete, of the designated class, required for the construction of walls that are not part of bridges or box culverts, completed and accepted. Miscellaneous concrete shall consist of the structural concrete of the designated class shown on the plans, except bridge, box culvert , or wall concrete, completed and accepted. Bridge Deck Finish (Sawed Grooves) will be measured by the square yard. The area includes the length of the bridge and approach slabs, with deductions for areas occupied by expansion devices as specified, multiplied by the width of the roadway between the faces of curb or bridge rail on each side, less 3.0 feet. Bridge Deck Finish (Sawed Grooves) will not be measured in the field but will be the quantity shown on the plans. Exceptions for each structure will be: 601.20 601-46
1.when field changes are ordered, or
2.when it is determined that there are discrepancies on the plans in an amount of plus or minus 2 percent of the plan quantity for the structure. When permanent deck forms are optional, bridge deck concrete and reinforcing steel shown on the plans, which are based on a conventionally reinforced deck, will be paid for per Sections 601 and 602, under Pay Item 601, Structural Concrete, and Pay Item 602, Reinforcing Steel. Quantities of bridge deck concrete and reinforcing steel will not be measured in the field, but will be the quantities shown on the plans, except when a p lan change is ordered or when it is determined that there are discrepancies in an amount of plus or minus 2 percent of the plan quantity. When permanent deck forms are required, bridge deck concrete and reinforcing steel will be paid for per Section 601 and 602, under Pay Item 601, Structural Concrete, and Pay Item 602, Reinforcing Steel. Quantities of bridge deck concrete and reinforcing steel will not be measured in the field, but will be the quantities shown on the plans, except when a pl an change is ordered or when it is determined that there are discrepancies in an amount of plus or minus 2 percent of the plan quantity. When precast panel deck forms are required, they will be measured and paid for per Section 618. Concrete and all reinforcing or prestressing steel required for the panels will not be measured and paid for separately but shall be included in the work. Structural Concrete Coating will not be measured in the field but shall be the surface area quantity shown on the plans; except those measurements to be made when field changes are ordered, or for an error of plus or minus 5 percent of the plan quantity for each structure to be coated. Maturity meters, thermocouples , and information cylinders will not be measured and paid for separately but shall be included in the work. BASIS OF PAYMENT
601.20 The accepted quantities will be paid for at the contract unit price per unit of
measurement for each of the pay items listed below that appear in the bid schedule. Payment will be made under: Pay Item Pay Unit Concrete Class _____ Cubic Yard Concrete, Class_____(Bridge) Cubic Yard Concrete, Class_____(Box Culvert) Cubic Yard Concrete, Class_____(Wall) Cubic Yard Concrete, Class_____(Miscellaneous) Cubic Yard Bridge Deck Finish (Sawed Grooves) Square Yard Structural Concrete Coating Square Yard Payment will be full compensation for all work necessary to complete the designated Pay Item per subsection 109.02. 601.21 601-47 Polyolefin fiber reinforcement will not be measured and paid for separately but shall be included in the work. Payment for structural concrete coating will be full compensation for all work and materials necessary to complete the item and shall include, but is not limited to:
1.Water based form release agent.
2.Sample preparation.
3.Abrasive blasting.
4.Patching materials and application.
5.Structural Concrete Coating and application. When requested by the Engineer, the Contractor shall provide the Engineer with a certified invoice from the coating supplier indicating the total volume of Structural Concrete Coating supplied to the project. Epoxy bonder material when specified on the plans will not be paid for separately but shall be included in the work. When permanent steel bridge deck forms are specified or allowed by the Contract, they will not be paid for separately but shall be included in the work, including all labor and additional concrete and other materials required to use these forms. Concrete finish is included in the work unless a separate pay item is included in the bid schedule. The Contractor’s PC testing will not be m easured and paid for separately but shall be included in the work. DESCRIPTION
601.21 This work consists of furnishing and placing concrete patching material on existing
bridge decks and expansion joint replacements per these specifications and in conformity with the lines, grades and dimensions as shown on the plans or established. MATERIALS
601.22 The concrete patching material may be pre -packaged Concrete patching material or
Class DR concrete.
a.Pre-Packaged Concrete Patching Material. Concrete patching material shall be polymer - modified hydraulic cement from the CDOT Approved Products List (Concrete/Repair/Patching/Class DR [Pre- Packaged ]). Concrete patching materials shall demonstrate 1/32 -inch maximum mid panel and end crack widths, 0 percent delamination, and 0 percent spalling as tested by National Transportation Product Evaluation Program (NTPEP) in a one- year field evaluation. The Contractor shall refer to rapid -set concrete patch materials at www.ntpep.org . 601.22 601-48 The Contractor shall obtain and provide to the Engineer documentation from the Concrete patching material supplier stating the expiration dates of the material components that will be used on the project. Concrete patching material shall attain an average compressive strength of at least 2,500 psi before placing traffic and 4,500 psi at 28 days. Concrete patching material compressive strengths shall be tested according to ASTM C39 or ASTM C109. The compressive strengths shall be used to develop a strength versus time curve for the material. Three stren gth data points shall be determined to assess the necessary time to wait before traffic is allowed on the material. Maturity meter data will be submitted t o allow the use of the maturity meter to determine when the patching material has gained the required strength for opening to traffic. Concrete patching material shall provide a minimum bond strength of 2,000 psi at 28 days, as tested by ASTM C882. Concrete patching material shall have a relative durability factor greater than 90 and a mass loss not to exceed 2.0 percent as tested by ASTM C666. Concrete patching material shall have a maximum expansion of 0.05 percent, at 28 days as tested by ASTM C157 ASTM C39, C109, C882 and C157 testing shall be from the same lot of concrete patching material being used on the project. A CTR, per subsection 106.13, shall be submitted to the Engineer for approval at least 2 weeks before placement. Two bags of the concrete patching material, and two bags of the extending aggregate if used, from the same lot to be used on the project shall be submitted to an accredited Lab to verify compressive strength, and set time properties, by the Contractor befo re the concrete patching material is to be used on the project. Test results shall be submitted to the Engineer for acceptance. Verification of the strength properties will be achieved if the test results are either equal in strength or stronger than tho se advertised. Verification of the set time will be achieved if the set time is equal or less than the advertised value. Testing shall be included in the cost of the materials. Test results from other projects using the same lot may be submitted. If th e project uses material from more than one lot, test results are required for each lot used.
b.Class DR Concrete. Class DR Concrete shall have an air content of 5 to 8 percent, a maximum water to cement ratio of 0.44, a minimum 6 -hour compressive strength of 2,500 psi , and a minimum 28-day compressive strength of 4,500 psi. The concrete mix shall consist of a minimum of 50 percent AASHTO M 43 Size No. 7 or Size No. 8 coarse aggregate by weight of total aggregate. Lab test results shall show that the unrestrained shrinkage is less than 0.0 50 percent when tested by CP -L 4103 and ASTM C1202 test resul ts shall not exceed 2500 coulombs at 56 days of age. ASTM C150 Type III cement may be used. Materials, proportioning, batching , and mixing requirements of subsections 601.03 through 601.07 shall apply to Class DR concrete. Concrete Class DR shall meet Sulfate Level 0 requirements. 601.23 601-49 The Contractor shall develop maturity relationships per CP 69. The Contractor shall provide a multi -channel maturity meter and all necessary wire and connectors. The Contractor shall be responsible for the placement and maintenance of the maturity meter and wire. Placement shall be as directed by the Engineer. CONSTRUCTION REQUIREMENTS 601.23
a.Pre-Packaged Concrete Patching Material. Concrete patching material shall be placed in the repair areas before the expiration date of the material. Proportions of all mix components shall be measured by volume measurement (number of bags of standard weight and quantity of water or liquid component in gallons or quarts). If partial bags are used the bagged mix, extending aggregate, and water shall be weighed on a calibrated scale provided by the Contractor. The Contractor shall submit the Concrete patching mater ial mix design for approval two weeks before any concrete patching material is placed. The Contractor shall also submit a method statement describing what type of equipment will be used to batch the patching material, including the type of mixer, the type of material, volume measures to be used, scales f or partial bags, procedures to e nsure accurate proportioning of the patching material components, and tools to be used in placing and finishing the surface of the patch. The Contractor shall produce a batch ticket for each mixed batch of concrete patching material with the following information shown on each ticket:
1.Project Number
2.Bridge Number
3.Structure Temperature
4.Date and Time of batch
5.Material Type, name, and manufacturer
6.Material expiration date
7.Weight or volume of bag mix concrete
8.Weight or volume of extending aggregate.
9.Weight or volume of water or liquid component
10.Location of placement (Lane and Station Limits) The tickets shall be available on site for CDOT personnel to inspect. Each day the Contractor shall provide to the Engineer tickets for each bridge in separate envelopes stating Project Number, Bridge Number, Date of Paving, Type of Material, Daily Total, and Cumulative Total. Concrete patching material minimum and maximum thicknesses shall be per the recommendation of the material manufacturer. Concrete patching material site preparation, batching, extending with aggregate, mixing, placement, placement during cold temperatures, consolidation, and curing shall be per the manufacturer’s recommendations. A mix may be extended up to 90 percent of the manufacturer’s maximum extension. The surface of concrete patching material shall have a similar texture as the adjacent driving surfaces. 601.24 601-50 The Contractor shall submit a report consisting of the mix proportions and compressive strength vs time curve information to the Engineer at least two weeks before the material is to be used on the project. Field cast cylinders or cubes shall be taken by a qualified testing representative and test results shall be submitted to the Engineer within 24 hours, each day deck patching material is placed with compressive strength determined at 24 hours according to ASTM C 39 or ASTM C109. Areas patched with Pre -Packaged Concrete Patching Material shall not be opened to traffic until concrete patching material has reached a compressive strength of 2,500 psi using the compressive strength versus time curve developed for the material. Areas of the deck patched with Pre- Packaged Concrete Patching Material shall not receive a waterproof membrane until 4 hours after placement.
b.Class DR Concrete. Class DR Concrete shall be placed per Class D concrete with the following changes: The area to be patched with Class DR Concrete shall be saturated surface dry before placement and shall be free of standing water at the time of placement. Portions of decks patched with Concrete Class DR shall not be opened to traffic until the concrete’s compressive strength, determined by CP 69, has achieved at least 2500 psi. Areas of the deck patched with Concrete Class DR shall not receive a waterproof membrane until the concrete patches have cured for a minimum of 5 days or have a moisture content of 5 percent or less as measured by a moisture meter approved by the Engineer. Concrete Class DR shall be cured until a compressive strength of at least 2500 psi has been achieved. The curing compound shall conform to ASTM C309, Type 2 applied at a rate of 1 gallon per 100 square feet. The curing compound shall be applied as a fine spray within 10 minutes of discontinuing the finishing operation. Before and during application the curing compound shall be kept thoroughly mixed. Curing blankets with a minimum R -value of 0.5 shall be provided and shall be placed as soon as they can b e placed without marring the surface. When the ambient temperature is below 50 °F, the Contractor shall maintain the concrete temperature above 50 °F during the curing period. METHOD OF MEASUREMENT
601.24 Concrete (Patching) will be measured and paid for as the actual quantity placed and
accepted by the Engineer. 601.25 601-51 BASIS OF PAYMENT
601.25 The accepted quantities will be paid for at the contract unit price per unit of
measurement for each of the pay items listed below that appear in the bid schedule. Pay Item Pay Unit Concrete Class DR Cubic Yard Payment for Concrete (Patching) will be full compensation for all the work, materials, tools, equipment, testing, and incidentals required to complete patching, excluding the special installation of anodes when specified, when required. Furnishing all appurtenances including the molding, curing , and breaking of cylinders or cubes for generating the strength versus time curve and for determining the information cylinder or cube strength will not be measured and paid for separately, but shall be included in the work. Concrete patching material or Class DR Concrete will not be measured and paid for separately but shall be included in the Concrete (Patching) bid item. 601.25 601-52 THIS PAGE INTENTIONALLY LEFT BLANK 602.01 602-1 SECTION 602 REINFORCING STEEL DESCRIPTION
602.01 This work consists of furnishing and placing reinforcing steel per these specifications
and in conformity with the plans. MATERIALS
602.02 Reinforcing steel and welded wire fabric that will be furnished either uncoated or epoxy
coated shall meet the requirements of subsection 709.01. The coating material shall be a light -colored powdered epoxy resin that will highlight rusting of untreated bar areas. Reinforcing steel that requires welding shall conform to ASTM A706. Welding shall be done per ANSI/AWS D1.4. All accessories, including reinforcing steel supports, ties, and splicers used in conjunction with reinforcing steel, shall be of the same, or compatible, coating as the reinforcing utilized. Reinforcing steel not identified on the plans as epoxy coated may be supplied as epoxy coated, at the Contractor's option, at no additional cost to the Department. Epoxy coated reinforcing steel may not be substituted for Stainless, Continuous Hot dipped Galvanized, Zinc Coated (Galvanized), and Chromium reinforcing alternatives . Reinforcing alternatives such as Stainless, Continuous Hot dipped Galvanized, Zinc-Coated (Galvanized), and Chromium reinforcing may be supplied for reinforcing steel or epoxy coated reinforcing, at the Contractor's option, at no additional cost or time to the Department as approved by the Engineer. Length of lap splices for epoxy -coated reinforcing steel shall be per AASHTO LRFD Bridge Design Specifications , unless otherwise specified. CONSTRUCTION REQUIREMENTS
602.03 Bar List . Two copies of a list of all reinforcing steel and bending diagrams shall be
furnished to the Engineer at the site of the work at least one week before the placing of reinforcing steel is begun. Such lists will not be reviewed for accuracy. The Contractor shall be responsible for the accuracy of the lists and for furnishing and placing all reinforcing steel per the details shown on the plans . Bar lists and bending diagrams that are included on the plans, do not have to be furnished by the Contractor. When bar lists and bending diagrams are included on the plans, they are intended for estimating approximate quantities. The Contractor shall verif y the quantity, size, and shape of the bar reinforcement against those shown on the plans and make all necessary corrections before ordering.
602.04 Protection of Materials. Reinforcing steel and its coating shall be protected at all
times from damage. When placed in the work, the reinforcing steel shall be free from dirt, loose mill scale, paint, oil, loose rust, or other foreign substance.
Source: Colorado Standard Specifications for Road and Bridge Construction, 2023 Edition. Pages 549–600 of 943.