346-1 Description.
Use a Department -approved concrete mix design composed of a mixture of portland cement, aggregate, water, admixtures, and supplementary cementitious materials . Deliver the portland cement concrete to the site of placement in a freshly mixed, unhardened state. Obtain concrete from a plant that is cur rently on the Department’s Production Facility Listing. Producers seeking inclusion on the list shall meet the requirements of Section 105. If the concrete production facility’s Quality Control (QC) Plan is suspended, the Contractor is solely responsible t o obtain the services of another concrete production facility with an accepted QC Plan or await the reacceptance of the concrete production facility’s QC Plan prior to the placement of any further concrete on the project. There will be no changes in the Co ntract Time because of the suspension, as described . Bear all delay costs and other costs associated with the concrete production facility’s QC Plan acceptance or reacceptance.
346-2 Materials.
346-2.1 General: Meet the following requirements:
Coarse Aggr egate ................................ ............................ Section 901 Fine Aggregate* ................................ .............................. Section 902 Portland Cement and Blended Cement ........................... Section 921 Water ................................ ................................ ...............Section 923 Admixtures** ................................ ................................ ..Section 924 Supplementary Cementitious Materials .......................... Section 929 *Use only silica sand except as provided in 902 . **Use products listed on the Department’s Approved Product List ( APL). Do not use materials containing hard lumps, crusts , or frozen matter, or that is contaminated with material s exceeding the specified limits in the above listed Sections.
346-2.2 Types of Cement: Unless a specific type of cement is designated in the Contract
Documents , use Type I, Type IL, Type IP, Type IT, Type IS, Type II, or Type III cement in all classes of concrete. Use Type IL, Type IT, or Type II for all mass concrete elements. Use only the types of cements designated for each environmental classification in structural concrete as shown in Table 346-1. A mix design for a more aggressive environment may be used in a less aggressive env ironmental condition. FY 2023-24 Return to Table of Contents Table 346-1 Cement Use by Environmental Classification Component Slightly Aggressive Environment Moderately Aggressive Environment Extremely Aggressive Environment (1) Bridge Superstructures Precast Superstructure and Prestressed Elements Type I or Type III Type I, Type IL, Type II, Type III, Type IP, or Type IS Type II, Type IL, Type III (2), Type IT or Ternary Blend Cast in Place Type I Type I, Type IL, Type II, Type IP, or Type IS Type II, Type IL, Type IT or Ternary Blend Bridge Substructures , Drainage Structures, and other Structures All Elements Type I or Type III Type I, Type IL, Type II, Type IP, or Type IS Type II, Type IL, Type IT or Ternary Blend Notes:
1.Cements used in a more aggressive environment may also be used in a less aggressive environment.
2.Type III cement may be used in an Extremely Aggressive Environment for precast superstructure and prestressed elements when the ambient temperature at the time of concrete placement is 60°F and below .
346-2.3 Supplementary Cementitious Materials : Supplementary cementitious
materials (SCMs) are required in all classes of concrete specified in Table 346-3. Nonreinforced concrete Class I (Seal) and Class I (Pavement), are exempted, and Class II when used in slightly aggressive environments . The quantity of portland cement that is replaced with SCMs must be on an equal weight replacement basis of the total cementitious materials in accordance with Table 346-2. When using Type IP, IS or IT blended cement s, the total quantity of SCMs, including the blended cement added separately at the concrete plant shall meet the requirements of Table 346-2.
346-2.3 1 Highly Reactive Pozzolans: Materials that have a very high degree of
pozzolanic reactivity due to t heir very fine particle sizes, including silica fume, metakaolin and ultrafine fly ash.
346-2.3 2 Binary Concrete Mixes : Concrete mixes containing portland cement
and one SCM.
346-2.3 3 Ternary Concrete Mixes : Concrete mixes containing portland cement
and any two SCMs. FY 2023-24 Return to Table of Contents Table 346-2 Cementitious Materials Concrete Mix Proportions (%) (Environmental classification is extremely aggressive, unless otherwise noted) Application Portland Cement Fly Ash Type F Slag Highly Reactive Pozzolans (4 and 5) Silica Fume Metakaolin Ultra-Fine Fly Ash General Use 50-82 18-50
51-79 18-40 3-9
63-77 15-25 8-12
63-77 15-25 8-12
30-45 10-20 45-60
30-50 50-70
36-43 50-55 7-9
33-42 50-55 8-12
33-42 50-55 8-12
Precast / Prestressed 70-85 (1) 15-30 (1)
50-82 18-50
51-79 18-40 7-9
63-77 15-25 8-12
63-77 15-25 8-12
30-40 10-20 50-60
30-50 50-70
36-43 50-55 7-9
33-42 50-55 8-12
33-42 50-55 8-12
Drilled Shaft 50-82 18-50
38-42 58-62
30-40 10-20 50-60
Mass Concrete 50-82 (2) 18-50 (2)
50-65 (3) 35-50 (3)
66-78 15-25 7-9
63-77 15-25 8-12
63-77 15-25 8-12
30-40 10-20 50-60
30-50 50-70
36-43 50-55 7-9
33-42 50-55 8-12
33-42 50-55 8-12
1.Slightly Aggressive and Moderately Aggressive environments.
2.For Concrete with Core Temperature T≤165°F.
3.For Concrete with Core Temperature T≥165°F.
4.A minimum concrete Surface Resistivity (SR) value of 29 kΩ -cm is required.
5.Highly reactive pozzolans may be used below the specified ranges to enhance strength an d workability when it is not required by the Contract Documents . A minimum concrete Surface Resistivity (SR) value is not required.
346-2.4 Aggregate s: Produce all concrete using Size No. 57, 67 or 78 coarse aggregate s.
Use Size No. 8, and Size No. 89 alone, only when approved by the Engineer. FY 2023-24 Return to Table of Contents Use Size No. 4 or larger blended with smaller size coarse aggregate as two components.
346-2.4 1 Optimized Aggregate Gradation: Improve the aggregate packing
density at the Contractor’s option, by adding an intermediate -size coarse aggregate in accordance with FM 5 -621 to produce combined aggregate gradation of fine, intermediate , and coarse aggregate sizes for the concrete mixes.
346-2.4 2 Lightweight fine aggregate (LWFA) for internal curing: At the
Contractor’s option, use LWFA to reduce the early -age concrete cracking by replacing some of normal fine aggregate with saturated LWFA.
346-2.5 Admixtures : Ensure admixtures are used in accordance with the manufacturer’s
recommend ations and meetin g the requirements of Section 9.2, Volume II of the Materials Manual.
346-3 Classification of Concrete .
346-3.1 General: The classifications of concrete are designated as Class I (Seal), Class I
(Pavement), Class II, Class II (Bridge Deck), Class III, Class IV, Class IV (Drilled Shaft), Class V, Class VI, and Class VII. The 28-day specified minimum compressive s trength, maximum water to cementitious materials ratio and target slump of each class are detailed in Table 346-3. The required air content for all classes of concrete is less than or equal to 6.0%. For purposes of this Specification the concrete is further classified as follows:
1.Conventional Concrete: The target slump is described in Table 346-3 with a tolerance of ± 1.5 inches.
2.Increased Slump Concrete: The maximum target slump is 7 inches with a tolerance of ± 1.5 inches when a Type F, G, I or II admixture is used .
3.Slip-form Concrete: The target slump is 1.5 inches with a tolerance of ± 1.5 inches. For Class I (Pavement), m eet the requirements of Section 350 .
4.Flowing Concrete: Request Engineer’s authorization to use flo wing concrete for cast-in-place applications . The target slump is 9 inches with a tolerance of ± 1.5 inches.
5.Self-Consolidating Concrete (SCC): Request Engineer’s authorization to use SCC for cast-in-place applications The minimum target slump flow is 22.5 inches with a tolerance of ± 2.5 inches.
346-3.2 Concrete Class Substituti ons: The Engineer may allow the s ubstitution of a
higher class concrete in lieu of the specified class concrete when the substituted concrete mixes are included as part of the QC Plan, or for precast concrete, the Precast Concrete Producer QC Plan. The sub stituted higher class concrete must meet or exceed the requirements of the specified class concrete. When the average compressive strength is less than the specified minimum compressive strength of the higher class mix design, notify the Engineer. Accept ance is based on the requirements in Table 346-3 for the specified class concrete.
346-3.3 Acceptance Requirements : The specified minimum 28 -day strengths,
maximum water to cementitious materials ratio (w/cm), and target slumps for each class of concrete are given in Table 346 -3. For lightweight concrete, acceptance requirements also include the hardened density specified in the Contract Documents . The calculation of the water to cementitious materials ratio (w/cm) is based on the total mass of cementiti ous materials including portland cement and any SCMs used in the mix. FY 2023-24 Return to Table of Contents Table 346-3 Compressive Strength, w/cm, and Slump of Concrete Classes Class of Concrete 28-day Specified Minimum Compressive Strength (f′c) (psi) Maximum Water to Cementitious Materials Ratio (pounds per pounds) Target Slump Value (inches) I (Seal) 3,000 0.53 8 I (Pavement) (1) 3,000 0.50 1.5 or 3 II (3) 3,400 0.53 3 (2) II (Bridge Deck) 4,500 0.44 3 (2) III 5,000 0.44 3 (2) IV 5,500 0.41(4) 3 (2) IV (Drilled Shaft) 4,000 0.41 8.5 V 6,500 0.37(4) 3 (2) VI 8,500 0.37(4) 3 (2) VII 10,000 0.37(4) 3 (2) Notes:
1.Meet the requirements of Section 350.
2.For increased slump concrete, flowing concrete, SCC and slip form concrete meet the requirements of 346 -3.1.
3.For precast three -sided culverts, box culverts, endwalls, inlets, manholes and junction boxes, the target slump value and air content will not apply. The maximum allowable slump is 6 inches, except as noted in (2). The Contractor is permitted to use concrete meeting the requirements of ASTM C478 (4,000 psi) in lieu of the specified Class II concrete for precast endwalls, inlets, manholes and junction boxes.
4.When silica fume or metakaolin is required, the maximum water to cementitious material ratio will be 0.35. When ultrafine fly ash is used, the maximum water to cementitious material ratio will be 0.30.
346-3.4 Acceptance of concrete at 56 days: Use concrete mix designs meeting the
specified compressive strength at 56 days at the Contractor’s option . Submit the request to the Engineer for approval. After the Engineer’s approval, notify the concrete producer to initiate the mix design approval process at least 90 days prior to th e anticipated concrete placement.
346-3.5 Durability for Concrete Construction:
346-3.5 1 Minimum Cementitious Materials Content: Ensure that the produced
concrete meets the minimum amount of cementitious materials content in Table 346-4. Table 346-4 Minimum Amount of Total Cementitious Materials Content (pounds per cubic yard of concrete) Concrete Class Environmental Classification Extremely Aggressive Moderately Aggressive Slightly Aggressive I (Seal) (1), I (Pavement) (1), and II, 470 II (Bridge Deck), III (2), IV, IV (Drilled Shaft), V, VI and VII 600 550 510 Notes:
1.Request the use of concrete mixes with a lower amount of total cementitious materials content at the Contractor’s option. The mix design must meet the requirements of Section 9.2 Volume II of the Materials Manual.
2.When precast three -sided culverts , box culverts, endwalls, inlets, manholes or junction boxes require a Class III concrete, minimum cementitious materials content may be reduced to 470 pounds per cubic yard. FY 2023-24 Return to Table of Contents
346-3.5 2 Chloride Content Limits : Use the following maximum allowable
chloride content limits for the concrete application and/or exposure environment shown: Table 346-5 Chloride Content Limits for Concrete Construction Application/Exposure Environment Maximum Allowable Chloride Content, (pounds per cubic yard of concrete) Non-Reinforced Concrete No Test Needed Reinforced Concrete Slightly Aggressive Environment 0.70 Moderately or Extremely Aggressive Environment 0.40 Prestressed Concrete 0.40 Suspend concrete placement immediately for every mix design if chloride test results exceed the limits of Table 346-5 until corrective measures are made. Submit an Engineering Analysis Scope in accordance with 6 -4 by a Specialty Engineer knowledgeable in the areas of corrosion and corrosion control, to determine if the material meets the intended service life of the structure on all concrete produced from the mix design failing chloride test results to the previous passing test results.
346-3.5 3 Surface R esistivity Test : Ensure that the concrete meets or exceeds a
Sr value of 29 kΩcm at 28 days or 56 days if specified, when a highly reactive pozzolan is specified in the Contract Documents .
346-4 Special Types of Concrete.
346-4.1 Drilled Shaft Concrete: Notify the Engineer at least 48 hours before placing
drilled shaft concrete. Obtain slump loss test results demonstrating that the drilled shaft concrete maintains a slump of at least 5 inches throughout the concrete elapsed time b efore drilled shaft concrete operations begin. Perform the slump loss test at the anticipated ambient temperature for drilled shaft placements greater than 30 cubic yards and an elapsed time of greater than five hours. Obtain slump loss test results fr om an approved laboratory or from a field demonstration. Slump loss test results for drilled shafts requiring 30 cubic yards of concrete or less and a maximum elapsed time of five hours or less may be done in a laboratory. Obtain all other slump loss test results in the field. The concrete elapsed time is defined in Section 455. Obtain the Engineer’s approval for use of slump loss test results including elapsed time before concrete placement begins. Test each load of concrete for slump to ensure that it is within the limits of this Section. Initially cure acceptance cylinders for 48 hours before transporting them to the laboratory. If the elapsed time during placement exceeds the slump loss test data, submit an Engineering Analysis Scope in accordance with 6-4 by a Specialty Engineer knowledgeable in concrete foundations, to determine if the shaft is structurally sound and free from voids . At the direction of the Engineer, excavate the drilled shaft for inspection. Obtain approval from the Engineer befo re placing any additional shafts. FY 2023-24 Return to Table of Contents
346-4.2 Mass Concrete: When the Contract Documents designate any structure as mass
concrete, use a Specialty Engineer to develop and administer a Mass Concrete Control Plan (MCCP). Develop the MCCP in accordance with Section 9.4 Volume II of the Materials Manual . Provide the Spe cialty Engineer a list of all concrete elements identified. Use a sequential identification code for each element indicating the bridge or structure number, location and type of element, least dimension size, and environmental exposure . Record core and differential temperatures for all structures included in the MCCP and monitor only the elements specified therein. Ensure that the concrete core temperatures do not exceed the maximum allowable temperature of 180°F and that the differential temperatures between the element core and surface do not exceed the maximum allowable temperature differential of 35°F. Submit the MCCP to the Engineer for approval at least 21 calendar days prior to the first anticipated mass concrete placement. Do not place concrete until the proposed MCCP has been approved. Any modifications must be submitted as addenda to the original MCCP and must be approved in writing by the Engineer. Install temperature measuring sensors and recording devices for all mass concrete elements in accordance with the MCCP. Do not add local additional insulation or external sources of heat around the surface sensors that affect the temperature readings . Ensure that, prior to the first concrete placement of each concrete element the Specialty Engine er or approved designee personally inspects the installation of the temperature measuring devices and verifies that the temperature data acquisition equipment is properly functioning. The Specialty Engineer shall be available for immediate consultation dur ing the monitoring period of any mass concrete element. Use temperature data acquisition equipment to record temperature readings in accordance with the MCCP. Within three workings days of the completion of temperature recording for each concrete elem ent, submit the Mass Concrete Field Report in accordance with Section 9.4, Volume II of the Materials Manual. For a group of elements, the Engineer may approve a monitoring reduction if the first element placed does not exceed either the maximum tempera ture or maximum temperature differential. Request written approval from the Engineer at least 14 calendar days prior to the anticipated date of the intended reduced monitoring. If approved, monitoring of the recorded temperatures is not required for the re maining elements meeting all of the following requirements:
1.All elements have the same dimensions.
2.All elements have the same concrete mix design.
3.All elements have the same insulation R value and active cooling measures (if used).
4.Ambient temperatures during concrete placement for all elements are within minus 10°F of the ambient temperature during placement of the initial element.
5.Use the same temperature control measures used for the initial monitored element and keep them in place for at least the same length of time as for the initial element. Resume monitoring of the temperatures for all elements if directed by the Engineer. FY 2023-24 Return to Table of Contents Instrumentation and temperature monitoring are not required for miscellaneous drilled shafts supporting sign, signal, lighting or Intelligent Transportation System (ITS) structures when the as built diameter is six feet or less, and the total cementiti ous materials content of the concrete mix design is less than or equal to 752 pounds per cubic yard. Monitoring of the recorded temperatures is not required for any mass concrete substructure element meeting all of the following requirements:
1.The minimum cross -sectional as -built dimension of the element is six feet or less.
2.Insulation with an R-value of at least 2.5 must be provided for at least 72 hours following the completion of concrete placement.
3.The environmental classification of the concrete element is slightly aggressive or moderately aggressive.
4.The concrete mix design mee ts the mass concrete proportioning requirements of 346 -2.3.
5.The total cementitious material content of the concrete mix design is less than or equal to 752 pounds per cubic yard.
6.Temperature of the concrete is 95°F or less a t placement. Implement immediate corrective action as directed by the Specialty Engineer when either the core temperature or the temperature differential of any mass concrete element exceeds its maximum allowable value. The approval of the MCCP shall be revoked. Submit an Engineering Analysis Scope in accordance with 6 -4 for approval, which addresses the structural integrity and durability of any mass concrete element that is not cast in compliance with the approved MCCP, or which exceeds the allowable core temperature or temperature differential. Submit all analyses and test results requested by the Engineer for any noncompliant mass concrete element. Submit a revised MCCP and do not place any mass concrete elements until a revised MCCP has been approved in writing by the Engineer . The Department will not provide compensation for additional costs or loss of time due to additional analyses, tests, or other impacts on production caused by not monitoring the recorded temperatures .
346-4.3 Flowing Concrete and Self -Consolidating Concrete (SCC) : Use Flowing
concrete or SCC when shown in the Contract Documents or to facilitate concrete placement in structures of complex geometric shape or highly reinforcement. Perform a field demonstration mockup using an approved mix desig n. Submit the mockup design to the Engineer for approval including the location of the sawcut. Cast a partial or full -scale mockup(s) and demonstrate through the successful production the ability to produce and place flowing concrete or SCC. The design , production, and evaluation product must meet the following requirements:
1.Use the proposed mix design(s).
2.Produce the mockup(s) at the jobsite, using the intended placement and curing methods, such as the use of ready -mix trucks, pumps, chutes , hopper, consolidation equipment, etc. The mockup shall contain reinforcing steel, mass concrete cooling pipes if required during construction, and other embedded items typical of the cast element.
3.Meet the requirements of the plastic properties inc luding the cutoff time. FY 2023-24 Return to Table of Contents
4.Meet the hardened properties and durability requirement when specified in the Contract Documents.
5.Concrete will be produced in the proposed concrete plant(s).
6.Concrete plant(s) representative(s) must be present dur ing mockup demonstration.
7.Notify the Engineer at least 7 days prior to mockup production.
8.If the production of the structural element that will be represented in the mockup requires concrete from multiple concrete plants, the concrete from each plant must be represented in the mockup.
9.Sawcut the mockup’s entire cross -section. Inspect and report for voids, honeycombing, and rock pockets, mix segregation, and other inclusions developed during placement of the concrete.
10.Determine the C oarse Aggregate Index of concrete in accordance with FM 5-617.
11.Complete the demonstration of a successful mockup prior to the beginning of concrete placement operations. Based on the inspection results of the field demonstration mockup, the accept ance of using flowing concrete or SCC in the structural element or section of the element is at the Engineer’s discretion. The required mockup demonstration may be omitted at the Contractor’s request. Submit documentation indicating successful experience of furnishing and placing flowing concrete or SCC on similar Department projects. Such documentation must list projects by date of completion, name or project reference number, structural elements or type of unit placed, quantity of concrete furnished, na mes and experience of personnel, and contact information for verification.
346-4.4 Lightweight Concrete: Submit the fresh and hardened concrete density for mix
design approval. The hardened density is the equilibrium density in ASTM C567. Ensure that the hardened density of the mix design is within ± 2 lb/ft3 of the hardened density specified in the Contract Documents. During production, the freshly mixed concrete density must be within ± 3 lb/ft3 of the approved mix design fresh density.
346-5 Sampling and Testing Methods.
Perform concrete sampling and testing in accordance with the following methods: Table 346-7 Concrete Sampling and Testing Methods Description Method Slump of Hydraulic Cement Concrete ASTM C143 Air Content of Freshly Mixed Concrete by the Pressure Method (1) ASTM C231 Air Content of Freshly Mixed Concrete by the Volumetric Method (1) ASTM C173 Making and Curing Test Specimens in the Field (2) ASTM C31 Compressive Strength of Cylindrical Concrete Specimens(3) ASTM C39 Obtaining and Testing Drilled Core and Sawed Beams of Concrete ASTM C42 Density of Structural Lightweight Concrete ASTM C567 Initial Sampling of Concrete from Revolving Drum Truck Mixers or Agitators FM 5-501 FY 2023-24 Return to Table of Contents Table 346-7 Concrete Sampling and Testing Methods Description Method Low Levels of Chloride in Concrete and Raw Materials FM 5-516 Density (Unit Weight), Yield and Air Content (Gravimetric) of Concrete ASTM C138 Temperature of Freshly Mixed Portland Cement Concrete ASTM C1064 Sampling Freshly Mixed Concrete (4) ASTM C172 Static Segregation of Self -Consolidating Concrete using Column Techniques ASTM C1610 Slump Flow of Self -Consolidating Concrete ASTM C1611 Relative Viscosity of Self -Consolidating Concrete ASTM C1611 Visual Stability Index of Self -Consolidating Concrete ASTM C1611 Passing Ability of Self -Consolidating Concrete by J -Ring ASTM C1621 Rapid Assessment of Static Segregation Resistance of Self -Consolidating Concrete Using Penetration Test ASTM C1 712 Aggregate Distribution of Hardened Self-Consolidating Concrete FM 5-617 Hardened Visual Stability Index of Self -Consolidating Concrete AASHTO R 81 Fabricating Test Specimens with Self -Consolidating Concrete ASTM C1758 Concrete Resistivity as an Electrical Indicator of its Permeability AASHTO T 358
1.The Department will use the same type of meter for Verification testing as use d for QC testing. When using pressure type meters, use an aggregate correction factor determined by the concrete producer for each mix design to be tested. Record and certify test results for correction factors for each type of aggregate at the concrete production facility.
2.Provide curing facilities that have the capacity to store all QC, Verification, and Resolution cylinders simultaneously for the initial curing. Cylinders will be delivered to the testing laboratory in their molds. The laboratory will remove the specimen s from the molds and begin final curing.
3.Lightweight concrete also includes hardened specimen density. T he ASTM C567 may be used in lieu of ASTM C39 to verify the density.
4.Take the test sample from the middle portion of the batch in lieu of collecting and compositing samples from two or more portions, as described in ASTM C172.
346-6 Quality Control.
346-6.1 General: Perform QC activities to ensure materials, methods, techniques,
personnel, procedures and processes utilized during production meet the specified requirements. For precast/prestressed concrete operations, ensure that the QC testi ng is performed by the producer. Accept the responsibility for QC inspections on all phases of work. Ensure all materials and workmanship incorporated into the project meet the requirements of the Contract Documents.
346-6.2 Concrete Mix Design: Provide concrete that has been produced in accordance
with a Department approved mix design, in a uniform mass free from balls and lumps. For slump target values in excess of 6 inches, including flowing concrete and SCC, utilize a grate over the conveyance equi pment to capture any lumps or balls that may be present in the mix. The grate must cover the entire opening of the conveyance equipment and have an opening that is a maximum of 2 -1/2 inches in any one direction. Remove the lumps and balls from the grate an d discard them. Discharge the concrete in a manner satisfactory to the Engineer. Perform demonstration batches to ensure complete and thorough placements in complex elements, when requested by the Engineer. Do not place concretes of different composition s such that the plastic concretes may combine, except where the Plans require concrete with a surface resistivity value of FY 2023-24 Return to Table of Contents 29 kΩcm or below and one with higher than 29 kΩ-cm values in a continuous placement. Produce these concretes using separate mix designs. For example, designate the mix with calcium nitrite as the original mix and the mix without calcium nitrite as the redesigned mix. Ensure that both mixes contain the same cement, fly ash or slag, coarse and fine aggregates and admixtures. Submit both m ixes for approval as separate mix designs, both meeting all requirements of this Section. Ensure that the redesigned mix exhibits plastic and hardened qualities which are additionally approved by the Engineer as suitable for placement with the original mix . The Engineer will approve the redesigned mix for commingling with the original mix and for a specific project application only. Alternately, place a construction joint at the location of the change in concretes as approved by the Engineer .
346-6.3 Delivery Certification: Ensure that an electronic delivery ticket is furnished
with each batch of concrete before unloading at the placement site. The delivery ticket may be proprietary software or in the form of an electronic spreadsheet, but shall be printed. Ensure that the materials and quantities incorporated into the batch of concrete are printed on the delivery ticket. Include the following information on the delivery ticket:
1.Arrival time at jobsite,
2.Time that concrete mix has been completely discharged,
3.Number of revolutions upon arrival at the jobsite,
4.Total gallons of water added at the jobsite,
5.Additional mixing revolutions when water is added,
6.Total number of revolutions. Items (3) through (6) do not apply to non -agitating concrete transporting vehicles. Ensure the batcher responsible for production of the batch of concrete signs the delivery ticket, certifying the batch of concrete was produced in accordance with the C ontract Documents. Sign the delivery ticket certifying that the design mix maximum specified water to cementitious materials ratio was not exceeded due to any jobsite adjustments to the batch of concrete, and that the batch of concrete was delivered and placed in accordance with the Contract Documents.
346-6.4 Plastic Property Tolerances: Reject concrete with slump or air content that
does not fall within the specified tolerances, except as noted below, and immediately notify the concrete production faci lity that an adjustment of the concrete mixture is required. If a load does not fall within the tolerances, test each subsequent load and the first adjusted load. If failing concrete is not rejected or adjustments are not implemented, the Engineer may reject the concrete and terminate further production until the corrections are implemented. At the Contractor’s risk, water may be added at the placement site immediately after completion of the initial slump or slump flow test, either to co rrect a low slump or slump flow, or to increase the concrete workability, provided the addition of water does not exceed the water to cementitious materials ratio as defined by the mix design. After adding water at the placement site depending on the typ e of concrete, perform the following tests:
1.Except for SCC, perform a slump test to confirm the concrete is within the slump tolerance range. If the slump is outside the tolerance range, reject the load.
2.For SCC, perform a slump flow and rapid assessment of static segregation resistance. Do not reject SCC exceeding the high -end slump flow tolerance if it has passed the rapid assessment of static segregation resistance test. Reject the load if the slump flow FY 2023-24 Return to Table of Contents is below the low -end tolerance. As an exception , the Engineer may accept the concrete if the rejection compromises the structural integrity of the element or produces other detrimental effects. Minimum vibration may be needed in accordance with Section 400. If an adjustment is made at the concrete production facility, perform a slump test on the next load to ensure the concrete is within the slump tolerance range s. Except for SCC, do not place concrete represented by slump test results outside of the tolerance range. Include water missing from the water storage tanks upon arrival at the project site in the jobsite water added. Do not allow concrete to remain in a transporting vehicle to reduce slump.
346-7 Mixing and Delivering Concrete.
346-7.1 General Requirements: Operate all concret e mixers at speeds and volumes per
the manufacturer’s design or recommendation as stipulated on the mixer rating plate.
346-7.2 Transit Truck Mixing: Produce a completely uniform mixed concrete in a truck
mixer for a minimum of 70 revolutions at the mixin g speed designated by the truck manufacturer. ` Prior to starting the discharge of the concrete at the jobsite, w hen water is added, record the added quantity and mix the concrete 30 additional drum mixing revolutions. Do not make more than two mix adjust ments. Seek approval from the Engineer prior to using a central mixer and depositing the batch into a truck mixer.
346-7.2 1 Transit Time: Ensure compliance with Table 346-8 between the initial
introduction of water into the mix and completely dischargin g all the concrete from the truck. Reject concrete exceeding the maximum transit time. The Engineer may approve an extension of the transit time which will be identified on the approved mix design. Table 346-8 Maximum Allowable Transit Time Non-Agitator Trucks Agitator Trucks 45 minutes 60 minutes 75 minutes (1) 90 minutes (1) Note:
1.When a water-reducing and retarding admixture (Type D, Type G , or Type II) is used.
346-7.2 2 Placement Time: All the concrete in a load must be in its final
placement position a maximum of 15 minutes after the transit time or cutoff time has expired unless a time extension is approved by the Engineer. As an exception, the Engineer may accept concrete that exceeds the transit time or cutoff time if the load passes the slump or slump flow tests. Place concrete in continuous manner in accordance with Section 400. For Class IV (Drilled Shaft) mixes, placement time may be extended provided the slump loss time of the first concrete placed is not exceeded throughout the elapsed time. The Engineer may perform Independent Verification (IV) testing to verify the plastic and hardened properties of the concrete when a time extension is granted.
346-7.3 On-site Batching and Mixing: Use a mixer of sufficient capacity to prevent
delays that may be detrimental to the quality of the work. Ensure that the accuracy of batching equipment is in accordance with requirements of this Section. FY 2023-24 Return to Table of Contents
346-7.4 Concreting in Cold Weather: Do not mix or place concrete when the air
temperature is below 40ºF. Protect the fresh concrete from freezing in accordance with Section 400. The requirements of concreting in cold weather are not applicable to precast concrete mixing and placement operati ons occurring in a temperature controlled environment.
346-7.5 Concreting in Hot Weather: Hot weather concreting is defined as the
production, placing and curing of concrete when the concrete temperature at placing exceeds 85ºF but is 100ºF or less. Unless the specified hot weather concreting measures are in effect, reject concrete exceeding 8 5ºF at the time of placement. Regardless of special measures taken, reject concrete exceeding 100ºF. Predict the concrete temperatures at placement time and impleme nt hot weather measures to avoid production shutdown.
346-7.6 Sample Location: Obtain acceptance samples from the point of final placement.
Where concrete buckets are used to discharge concrete directly to the point of final placement or into the hopper of a tremie pipe, samples will be obtained from the discharge of the bucket. When the concrete is discharged directly from the mixer into the bucket and the bucket is discharged within 20 minutes, samples may be obtained from the discharge of the mixer. Where conveyor belts, troughs, pumps, or chutes are used to transport concrete directly to the point of final placement or into the hopper of a tremie pipe, samples will be obtained from the discharge end of the entire conveyor belt, trough, pump, or chut e system. Where concrete is placed in a drilled shaft or other element using a tremie pipe and a concrete pump, samples will be obtained from the discharge of the pump line at the location of the tremie hopper. For all other placement methods, prior to each placement, obtain Department approval for sampling at the discharge of the mixer in lieu of sampling at the point of final placement. Submit the sampling correlation procedure to the Engineer for approval prior to the placement of the concrete. Once the comparative sampling correlation is approved by the Engineer, apply this correlation to the plastic properties tolerances for samples obtained from the discharge of mixer. Where a concrete pump is used to deposit concrete directly into a drilled shaft which is a wet excavation without the use of a tremie, or other applications as approved by the Engineer, ensure the discharge end of the pump line remains immersed in the conc rete at all times after starting concrete placement.
346-8 Plastic Concrete Sampling and Testing.
QC tests include air content, temperature, slump, and preparing cylinders for testing at later dates with the following exceptions: with the following except ions: For Class I (Pavement), the air content testing is not required. For Lightweight concrete , tests also include the plastic density (unit weight). For SCC, QC tests also include slump flow in lieu of slump, visual stability index , and rapid assessme nt of static segregation. In addition, calculate the water to cementitious materials ratio in accordance with FM 5-501 for compliance to the approved mix design. Ensure that each truck has a rating plate and a valid mixer identification card issued by the Department. Ensure that the revolution counter on the mixer is working properly, and calibration of the water dispenser has been performed within the last twelve months. Reject any FY 2023-24 Return to Table of Contents concrete batches that are delivered in trucks that do not have mixer iden tification cards. Remove the mixer identification card when a truck mixer is discovered to be in noncompliance and the mixer deficiencies cannot be repaired immediately. When the mixer identification card is removed for noncompliance, make note of the defi ciency or deficiencies found, and forward the card to the District Materials and Research Engineer who has Producer QC Plan acceptance authority. Perform plastic concrete tests on the initial delivery from each plant of each concrete design mix each day. Ensure QC technicians meeting the requirements of Section 105 are present and performing tests throughout the placement operation. Ensure a technician is present and performing tests throughout the placement operation at each placement site. If a project h as multiple concrete placements at the same time, identify the technicians in the QC Plan to ensure minimum sampling and testing frequencies are met. Ensure that the equipment used for delivery, placement and finishing meets the requirements of this Specif ication. When a truck designated for QC testing arrives at the discharge site, a subsequent truck may also discharge once a representative sample has been collected from the QC truck and while awaiting the results of QC testing. Reject non -complying loads at the jobsite. Ensure that corrections are made on subsequent loads. Immediately cease concrete discharge of all trucks if the QC truck has failing test. Perform plastic properties tests of concrete on all trucks prior to the first corrected truck and th e corrected truck. When more than one truck is discharging into a pump simultaneously, only the truck designated for QC testing may discharge into the pump to obtain a representative sample of concrete from the QC truck only. Furnish sufficient concrete o f each design mix as required by the Engineer for verification (VT) testing. When the Engineer’s VT test results do not compare with the QC plastic properties test results, within the limits defined by the Independent Assurance (IA) checklist comparison criteria, located in Materials Manual Chapter 5, disposition of the concrete will be at the option of the Contractor. On concrete placements consisting of only one load of concrete, perform initial sampling and testing in accordance with this Section. The acceptance sample and plastic properties tests may be taken from the initial portion of the load. If any of the QC plastic properties tests fail, reject the remainder of that load, and any other loads that have begun discharging, terminate the LOT and notify the Engineer. Make cylinders representing that LOT from the same sample of concrete. Following termination of a LOT, obtain samples from a new load, and perform plastic properties tests until the water to cementitious materials ratio, air content, temperature and slump comply with the Specification requirements. Initiate a new LOT once the testing i ndicates compliance with Specification requirements. Suspend production when any five loads in two days of production of the same design mix are outside the specified tolerances. Increase the frequency of QC testing to one per load to bring the concrete w ithin allowable tolerances. After production resumes, obtain the Engineer’s approval before returning to the normal frequency of QC testing. If concrete placement stops for more than 90 minutes, perform initial plastic properties testing on the next batch and continue the LOT. Cylinders cast for that LOT will represent the entire LOT. When the Department performs Independent Verification (IV), the Contractor may perform the same tests on the concrete at the same time. The Department will compare results based on the Independent Assurance (IA) Checklist tolerances. FY 2023-24 Return to Table of Contents
346-9 Acceptance Sampling and Testing.
346-9.1 General: Perform plastic properties tests in accordance with 346 -8 and cast a set
of three QC cylinders, for all structural concrete incorporated i nto the project. Take these acceptance samples randomly as determined by a random number generator acceptable to the Department. The Department will independently perform VT plastic properties tests and cast a set of VT cylinders. The VT cylinders will be the same size cylinder selected by the Contractor, from a separate sample from the same load of concrete as the Contractor’s QC sample. For each set of QC cylinders verified by the Department, cast two additional cylinders from the same sample, and ident ify them as the quality control resolution (QR) test cylinders. The Department will also cast two additional verification resolution (VR) test cylinders from each VT sample. All cylinders will be clearly identified as outlined in the Sample/LOT Numbering S ystem instructions located on the State Materials Office website. Deliver the QC samples, including the QR cylinders to the final curing facility in accordance with ASTM C31. Concurrently , the Department will deliver the VT samples, including the VR cylinders, to their final curing facility . Test the QC laboratory cured samples for compressive strength at the age of 28 days, in a laboratory meeting and maintaining at all times the qualification requirements listed in Section 105. Ensure the QC testing l aboratory input the compressive strength test results into the Department’s Materials Acceptance and Certification (MAC) system within 24 hours after testing. Notify the Engineer when results cannot be input ted into MAC . The Department will compare the VT sample compressive strength test results with the corresponding QC sample test results.
346-9.2 Sampling Frequency: As a minimum, sample and test concrete of each mix
design for water to cementitious materials ratio, air content, temperature, slump and compressive strength once per LOT as defined by Table 346-9. The Engineer will randomly verify one of every four consecutive LOTs of each mix design based on a random number generator. The Department may perform Independent Verification (IV) testing to verify compliance with specification requirements. All QC activities, calculations, and inspections will be randomly confirmed by the Department. Table 346-9 Sampling Frequency Class Concrete (1) LOT Size I (Seal) Each seal placement I (Pavement) According to Section 350 II, II (Bridge Deck), III, IV, V, VI , VII 50 cubic yards, or one day’s production, whichever is less IV (Drilled Shaft) 50 cubic yards, or one day’s production , whichever is less (2)
1.For any class of concrete used for roadway concrete barrier , the lot size is defined as 100 cubic yards, or one day’s production, whichever is less.
2.Start a new LOT when there is a gap of more than two hours between the end of one drilled shaft placeme nt and the beginning of the next drilled shaft placement. FY 2023-24 Return to Table of Contents
346-9.2 1 Reduced Frequency for Acceptance Tests: Except for Class I
(Pavement), t he LOT size may represent 100 cubic yards when produced with the same mix design at the same concrete production facility for the same prime Contractor and subcontractor on a given Contract. As an exception, the requirements for the precast/prestressed production facility will only include the same mix design at th e same concrete production facility. The reduced testing frequency of Class I (Pavement) is described in the Section 350. Submit strength test results indicating that the two following criteria are met:
1.The average of the acceptance compressive s trengths is equal to or greater than the specified minimum compressive strength ( f′c) plus 2.33 standard deviations minus:
a.500 psi, if f′c is 5,000 psi or less.
b.0.10 f′c, if f′c is greater than 5,000 psi.
2.Every average of three consecutive strength test equals or exceeds the f′c plus 1.34 standard deviations. Base calculations on a minimum of ten consecutive strength test results for a Class IV or higher; or a minimum of five consecutive strength results for a Class III or lower. The average of the consecutive compressive strength test results, based on the class of concrete, can be established using historical data from a previous Department project. The tests from the previous Department project must be wi thin the last calendar year or may also be established by a succession of samples on the current project. Only one sample can be taken from each LOT. Test data must be from a laboratory meeting the requirements of Section 105. Obtain Department approval be fore beginning reduced frequency LOTs. If at any time a strength test is not verified or the average strength of the previous ten or five consecutive samples based on the class of concrete from the same mix design and the same production facility does not conform to the above conditions , return to the frequency represented by the LOT as defined in Table 346-9. Notify the Engineer that the initial frequency is reinstated. In order to reinitiate reduced frequency, submit a new set of strength test results.
346-9.3 Strength Test Definition: The strength test of a LOT is defined as the average
compressive strength tests of at least two companion cylinders cast from the same sample of concrete and tested at the same age .
346-9.4 Acceptance of Concrete: The Engineer will accept the concrete of a given LOT
when the compressive strength test results are verified and meets the minimum specified compressive strength in Table 346-3. Ensure that the hardened concrete strength test results are obtained in accord ance with 346 -9.3. The process of concrete compressive strength verification and acceptance consists of the following steps :
1.Verification of QC and VT data.
2.Resolution of QC and VT data if needed.
3.Structural Adequacy determination . Do not discard a cylinder strength test result based on low strength (strength below the specified minimum strength as per the provisions of this Section). When one of the three QC cylinders from a LOT is lost, missing, damaged or destroyed, determination of compressive strength will be made by averaging the remaining two cylinders. If more than one QC cylinder from a LOT is lost, missing, damaged or destroyed, the FY 2023-24 Return to Table of Contents Contractor will core the structure at no additional expense to the Department to determine th e compressive strength. Prior to coring, o btain Engineer ’s approval for coring the structure and its proposed coring location. Acceptance of LOT may be based on VT data at the discretion of the Engineer. For each QC and each Q R cylinder that is lost, mis sing, damaged or destroyed, payment for that LOT will be reduced by $750.00 per 1,000 psi of the specified design strength [Example: loss of two Class IV (Drill Shaft) QC cylinders that has no VT data will require the element to be cored and a pay reductio n will be assessed (4,000 psi / 1,000 psi) x $750 x 2 = $6,000]. This reduction will be in addition to any pay adjustment for low strength.
346-9.4 1 Small Quantities of Concrete: When a project has a total plan quantity
of less than 50 cubic yards, that concrete will be accepted based on the satisfactory compressive strength of the QC cylinders. Submit certification to the Engineer that the concrete was batched and placed in accord ance with the Contract Documents. Submit a QC Plan for the concrete placement operation in accordance with Section 105. The Engineer may perform IV testing as identified in 346 -9 and evaluate the concrete in accordance with 346 -9.7.
346-9.5 Verification : The results of properly conducted test by QC and VT laboratories
on specimens prepared from the same sample of concrete are not to differ by more than 14%. Difference (%) =ABS (QC−VT QC)100 Where: Difference (%) is the absolute percentage difference between QC and VT average compressive strength . The procedure consists of verifying if the QC and VT compressive strengths data meet the established comparison criteria:
1.When the difference betwee n the average compressive strength of QC and the average compressive strength of VT is less than or equal to 14%, the QC test results are upheld and verified. The Engineer will accept at full pay only LOTs of concrete represented by plastic property results which meet the requirements of the approved mix design and strength test results which equal or exceed the respective specified minimum strength.
2.When the difference between the average compressive strength of QC and the average compressive strength of VT data exceeds 14%, the compressive strength results are not verified and the Engineer will initiate the resolution procedure . Maintain the QR and VR cylinders for a minimum of 30 days following the testing date of the specified strength.
346-9.6 Resolution: The Engineer will perform the resolution process to identify the
reliability of the compressive strength results when the difference between the average compressive stre ngth of QC and the average compressive strength of VT data exceeds 14% as described in 346 -9.5(2). The Engineer will estimate the 28-day strength s (VR28 and QR 28) for the VR and QR cylinders using the following equation: Estimated 28 -Day Compressive Str ength (psi) = (Average Strength at (t) days -17.8 + 46.3[ln (t)] − 3.3[ln (t)]2)100 Where: FY 2023-24 Return to Table of Contents
t.is the elapsed number of days from concrete placement to the resolution cylinders testing. ln (t) is the natural logarithm of (t). The Engineer will compare:
1.The VT sample results with the VR28 cylinders results.
2.The QC sample results with the QR28 cylinders results . Comparison results must not be greater than 17.5%. Core samples of the hardened concrete may be required. VD (%) =ABS (VT−VR 28 VT)100 QD (%) =ABS (QC−QR 28 QC)100 Where: VD (%) is the absolute percentage difference between VT and VR 28. QD (%) is the absolute percentage difference between QC and QR 28. Perform the resolution with the concrete compressive strength data at 56 days in lieu of the 28 days when the acceptance of concrete is at 56 days. The resolution procedure will use the above equations. The Engineer will determine through the resolution procedure whether the QC strength test results or the VT strength test are deemed to be the most accurate, LOT s will then be considered to be verified. The Engineer will inform the QC and VT laboratories within three cal endar days of the acceptance compressive strength test to transport their QR and VR cylinders to the resolution lab oratory. The QC and VT laboratories will transport their own hold cylinder s to the resolution testing laboratory within three calendar days after the Engineer notifies the Contractor that a resolution procedure is required. In addition, the Engineer will ensure that the Q R and VR cylinders are tested within 14 calendar days of the acceptance strength tests. The Engineer will d etermine the most accurate strength test result to represent the four or fewer consecutive LOTs as follows:
1.When both results meet the established comparison criteria, both are deemed accurate and t he QC strength will represent the LOTs. The Department will pay for cost of the resolution testing.
2.When only the QC result is within the established comparison criteria, the QC strength is deemed as most accurate and will represent the LOTs . The Department will pay for the cost of the resolution testing.
3.When only the VT result is within the established comparison criteria, the VT strength is deemed as most accurate and will represent the LOTs. The Department will assess a $1,000 pay reduction for the cost of the Resolution Investigation .
4.When both results are outside the established comparison criteria, the Engineer, with input from the DMO, will determine if any Department IA evaluations are required and which test results are most accurate. The Department will pay for the cost of the resolution testing. When the Engineer cannot determine which strength test results are the most accurate, the concrete represented by the four consecutive LOTs will be evaluated based on the QC data. FY 2023-24 Return to Table of Contents The results of the resolution procedure will be forwarded to the Contractor within five working days after completion of the investigation.
346-9.7 Structural Adequacy : The Engineer will evaluate the structural adequacy for
verified concrete that does not meet the minimum specified compressive strength of Table 346-3. For structural adequacy, with standard molded and cured compressive strength cylinders, the compressive strength of concrete is satisfactory provided that the two following criteria are met:
1.The average compressive strength does not fall below the specified minimum compressive strength by more than:
a.500 psi if the specified minimum compressive strength is equal to or less than 5,000 psi.
b.10% of the specified minimum compressive strength if the specified minimum compressive strength is greater than 5,000 psi.
2.The average compressive strength with the previous two LOTs is equal to or exceed s the specified minimum compressive strength. This condition only applies i f there are two or more previous LOTs to calculate the average. The Engineer will consider the concrete for a given LOT as structurally adequate and coring will not be allowed when a concrete compressive strength test result falls below the specified min imum strength but has met the above conditions .
346-9.7 1 Lightweight concrete: The Engineer may require an Engineering
Analysis Scope in accordance with 6 -4 to establish structural and durability adequacy when the lightweight concrete plastic density (u nit weight) is outside of the specified tolerances.
346-10 Investigation of Low Compressive Strength Concrete.
When a verified concrete compressive strength test result falls below the specified minimum strength, and does not meet the structural adequacy described in 346 -9.7, perform one of the following options:
1.Submit an Engineering A nalysis Scope in accordance with 6 -4 to establish structural and durability adequacy . When the scope is approved by the Engineer, submit an Engineering Analysis Report (EAR) in accordance with 6 -4 that includes a full structural analysis. If the results of the structural analysis indicate adequate strength to serve its intended purpose with adequate durability, and is approved by the Engineer, the Contractor may leave the concrete in place subject to the requirements of 346-11, otherwise, remove and replace the LOT of concrete in question at no additional expense to the Department .
2.At the Engineer’s discretion, obtain drilled core samples as specified in this Section to determine the in -place strength of the LOT of concrete in question , at no additional expense to the Department. The Engineer will determine whet her to allow coring of the in -place concrete or require an engineering analysis based on the compressive strength of the test cylinders.
346-10.1 Coring for Determination of Structural Adequacy: Core strength test results
obtained from the structure will be accepted by both the Contractor and the Department as the in - place strength of the LOT of concrete in question. The core strength test results will be used in lieu of the cylinder strength te st results for determination of structural adequacy. The Depar tment will calculate the strength value to be the average of the compressive strengths of the three individual cores. This will be accepted as the actual measured value. Obtain and test the cores in accordance with ASTM C42.The Engineer will select the size and location of the drilled cores so that the structure is not impaired and does not sustain FY 2023-24 Return to Table of Contents permanent damage after repairing the core holes. Obtain the Engineer’s written approval before taking any concrete core sample. N otify the Engineer 48 hours prior to taking core samples. Sample three undamaged cores taken from the same approximate location where the questionable concrete is represented by the low strength concrete test cylinders. Repair core holes after samples ar e taken with a product in compliance with Section 930 or 934 and meeting the approval of the Engineer . Report the test results to the Enginee r within two calendar days of testing the core samples. The Engineer , with input from the DMO, will consider the concrete as structurally adequate, in the area represented by core tests at the actual test age , if the average compressive strength of cores does not fall below the specified minimum compressive stren gth (f′c) by more than:
a.500 psi when the f′c is equal to or less than 5,000 psi.
b.10% of the f′c when the f′c is greater than 5,000 psi. The Engineer may also require the Contractor to perform additional testing as necessary to determine structural adequacy of the concrete.
346-11 Pay Adjustments for Low Compressive Strength Concrete.
346-11.1 General: For any LOT of concrete failing to meet the f′c as defined in 346-3,
346-9, and satisfactorily meeting all other requirements of the Contract Documents, including structural adequacy, the Engineer will individually reduce the price of each low strength LOT in accordance with this Section.
346-11.2 Basis for Pay Adjustments: The Engineer will determine payment reductions
based on the 28 -day compressive strength, represented by either acceptance compressive strength or correlated cores strength test results based on the following criteria:
1.When the acceptance compressive strength test result falls below the specified minimum compressive strength, but no more than the limits established in 346-9.7 below the specified minimum strength, do not core hardened concrete for determining pay adjustments. Use the acceptance compressive strength test results .
2.When the acceptance compressive strength test result falls below the specified minimum compressive strength by more than the limits established in 346 -9.7, the structure may be cored for determination of structural a dequacy as directed by the Engineer. Use the result of the 28-day correlated core compressive strength or the acceptance compressive strength test, whichever is less. A price adjustment will be applied to the certified invoice price the Contractor paid for the concrete or the precast product. The Engineer will relate the strength at the actual test age to the 28 -day strength for the design mix represented by the cores using appropriate strength time correlation equations. In precast concrete operation s, excluding prestressed concrete, ensure that the producer submits acceptable core sample test results to the Engineer. The producer may elect to use the products in accordance with this Section . Otherwise, replace the concrete in question at no additiona l cost to the Department. For prestressed concrete, core sample testing is not allowed for pay adjustment. The results of the cylinder strength tests will be used to determine material acceptance and pay adjustment.
346-11.3 Calculatin g Pay Adjustments: The Engineer will determine payment
reductions for low strength concrete accepted by the Department . The 28-day strength is represented by either cylinder s or correlated cores strength test results in accordance with
346-11 2.
FY 2023-24 Return to Table of Contents Reduction in Pay is equal to the reduction in percentage of concrete compressive strength below the specified minimum strength : Reduction in Pay (%) =(f′c−28 day Strength f′c)100 For the elements that payments are based on the per foot basis, the Engineer will adjust the price reduction from cubic yards basis to per foot basis, determine the total linear feet of the elements that are affected by low strength concrete samples and apply the adjusted price reduction accordingly. Use the concrete com pressive strength data at 56 days in lieu of the 28 days when the acceptance of concrete is at 56 days.
346-12 Pay Reduction for Plastic Properties .
A rejected load in accordance with 346 -6.4 is defined as the entire quantity of concrete contained within a single ready -mix truck or other single delivery vehicle regardless of what percentage of the load was placed. If concrete fails a plastic properties test and is thereby a rejected load but its placement continues after completion of a plastic properties test having a failing result, payment for the concrete will be reduced. The pay reduction for cast -in-place concrete will be twice the certified invoice price per cubic yard of the quantity of concrete in the rejected load. The pay reduction for placing a rejected load of concrete into a precast product will be applied to that percentage of the precast product that is composed of the concrete in the rejected load. The percentage will be converted to a reduction factor which is a numerical value greater than zero but not greater than one. The precast product payment reduction will be twice the Contractor’s billed price from the producer for the precast product multiplied by the reduction factor. If the Engineer authorizes placement of the concrete, even th ough plastic properties require rejection, there will be no pay reduction based on plastic properties failures; however, any other pay reductions will apply. FY 2023-24 Return to Table of Contents SECTION 347 PORTLAND CEMENT CONCRETE - CLASS NS
347-1 Description.
The requirements of this Section are applicable to concrete designated as nonstructural portland cement concrete, ( Class NS) hereinafter referred to as concrete. Use concrete composed of a mixture of portland cement, aggregates, water ; and where specified chemical admixtures, or supplementary cementitious materials. Deliver concrete to placement site in a freshly mixed, unhardened state. Ensure the concrete is placed and cured in a manner to ensure that the strength and durability of the concrete is maintained.
347-2 Materials.
347-2.1 General: Certify that all materials used in concrete are from Department
approved sources, and free from detrimental matter. Meet the following requirements: Portland Cement ................................ ......Section 921 Coarse Aggregate* ................................ ..Section 901 Fine Aggregate* ................................ ......Section 902 Water ................................ ....................... Section 923 Chemical Admixtures ............................. Section 924 Supplementary Cementitious Materials ..Section 929 * Recycled Asphalt Pavement (RAP) may replace up to 20% of the total aggregate in the design mix. Use RAP from a Department approved stockpile.
347-3 Production, Mixing and Delivery.
347-3.1 Concrete Production Requirements: Obtain concrete from a plant that i s
currently on the Department’s Nonstructural Concrete Production Facility Listing. Producers seeking inclusion on the list must contact the local District Materials Office for approval. When Volumetric Mixers are used, deliver concrete in accordance wit h the Volumetric Mixer Standards of the Volumetric Mixer Manufacture rs Bureau (VMMB ) VMMB 100-01. Substitution of structural concrete in lieu of non -structural concrete may be used if approved by the Engineer. If structural concrete is used in lieu of n on-structural concrete, obtain the concrete from a production facility meeting the requirements of Section 346. Acceptance is based on the requirements of Section 347. The Engineer may disqualify any concrete production facility for non -compliance with Specification requirements.
347-3.2 Delivery: The maximum allowable mixing, agitation, and placement time of
concrete is 120 minutes.
347-3.3 Small Quantities of Concrete: With approval of the Engineer, small quantities
of concrete, less than 3 cubic yards placed in one day and less than 0.5 cubic yards placed in a single placement may be accepted using a pre -bagged mixture.
347-4 Certification and Acceptance.
347-4.1 General: Furnish a delivery ticket with each batch of concrete before
discharging concrete at the placement site. Ensure the delivery ticket includes material quantities FY 2023-24 Return to Table of Contents
Source: Florida Standard Specifications for Road and Bridge Construction, 2024 Edition. Pages 343–363 of 1,299.