498 SECTION 604 – CONCRETE STRUCTURES
604.01 Description ................................ ................................ ................... 499
604.02 Materials ................................ ................................ ...................... 499
604.03 Classification, Proportioning and Quality Assurance of
Concrete ................................ ................................ ....................... 501
604.04 Equipment ................................ ................................ .................... 510
604.05 Forms ................................ ................................ ........................... 516
604.06 Falsework ................................ ................................ ..................... 522
604.07 Camber ................................ ................................ ......................... 523
604.08 Reinforcement ................................ ................................ .............. 524
604.09 Drainage and Weep Holes ................................ ............................ 527
604.10 Placing Pipes, Conduits, Anchors, Casting, and other
Appurtenances ................................ ................................ ............. 527
604.11 Handling, Measuring, and Batching Materials ............................. 527
604.12 Mixing Limitations ................................ ................................ ....... 530
604.13 Mixing Concrete ................................ ................................ .......... 530
604.14 Consistency of Concrete ................................ .............................. 532
604.15 Compressive Strength Tests of Concrete ................................ ..... 532
604.16 Placing Concrete ................................ ................................ .......... 534
604.17 Bonding Construction Joints ................................ ........................ 539
604.18 Depositing Concrete Under Water ................................ ............... 539
604.19 Removal of Forms and Falsework ................................ ............... 541
604.20 Defective Concrete ................................ ................................ ....... 541
604.21 Finishing Concrete Surfaces ................................ ......................... 542
604.22 Finishing Slab Surfaces for Pavements or Bases ......................... 545
604.23 Curing Concrete ................................ ................................ ........... 547
604.24 Protection of Concrete in Cold Weather ................................ ...... 549
604.25 Painting Metals ................................ ................................ ............ 549
604.26 Waterproofing and Waterstops ................................ ..................... 549
604.27 Rideability of New or Resurfaced Bridge Decks and Roadway
Approaches ................................ ................................ .................. 550
604.28 Loading and Opening to Traffic ................................ ................... 552
604.29 Final Cleanup ................................ ................................ ............... 553
604.01 499 604.30 Method of Measurement ................................ .............................. 553
604.31 Basis of Payment ................................ ................................ .......... 556
DESCRIPTION
604.01 Description
This work consists of constructing all structures or parts of structures composed of Portland cement concrete, whether plain, reinforced, or a combination of both, on prepared foundations, at the locations shown on the Plans or as directed by the Engineer. Use concrete consisting of a mixture or mixtures of Portland cement, aggregates, air -entraining agents, water, and chemical additives when approved, combined by the methods specified herein and in the proportions specified for the designated class of co ncrete. Construct parts of a structure, or structures, which are to be constructed with materials other than Portland cement concrete and concrete reinforcement steel, as specified in the Section of these Specifications covering the particular type of cons truction. MATERIALS
604.02 Materials
A.General Provide materials as specified in: Hydraulic cement ................................ ................................ ... 901.01 Fine Aggregate, (all Classes of concrete) .............................. 903.01 Coarse Aggregate ................................ ................................ ... 903.03 Lightweight Aggregate ................................ .......................... 903.19 Joint Filler, Preformed Type ................................ .................. 905.01 Steel Bar Reinforcement ................................ ........................ 907.01 Welded Steel Wire Fabric ................................ ...................... 907.03 Structural Steel ................................ ................................ ....... 908.01 Permanent Steel Bridge Deck Forms ................................ ..... 908.03 Steel Castings ................................ ................................ ........ 908.05 Gray Iron Castings ................................ ................................ . 908.07 604.02 500 Bronze Bearing Plates, Plain ................................ .................. 908.09 Bronze Bearing Plates, Self -Lubricating ................................ 908.10 Elastomeric Bearing Pads ................................ ...................... 908.12 Paints ................................ ................................ ........................... 910 Cement Concrete Curing Materials ................................ ............. 913 Precast Concrete Box Culverts ................................ .............. 914.08 Water ................................ ................................ ...................... 921.01 Chemical Admixtures and Additives ................................ ..... 921.06 Air-Entraining Admixtures ................................ .................... 921.06 Waterstops ................................ ................................ ............. 921.08 Precast Prestressed Bridge Deck Panels ................................ 921.13 Applied Texture Finish ................................ .......................... 921.14 Fly Ash ................................ ................................ ................... 921.15 Slag Cement ................................ ................................ ........... 921.16
B.Fly Ash and Slag Cement Do not use f ly ash or slag cement of different classes or sources as partial replacement for Portland cement in concrete mixes.
C.Precast Box Sections Unless otherwise shown on the Plans, for f ill heights less than or equal to those shown in the standard box culvert drawings for cast -in-place concrete box sections , the Contractor may substitute precast reinforced box sections meeting 914.08 and the standard box culvert drawings for precast box culverts. Submit shop drawings of the proposed precast box section and design calculations for approval before construction. As a minimum, the shop drawings shall include a plan and elevation view of the box culvert showing all precast sections, a typical precast box section showing dimensions and reinforcing, and notes and details required for construction. After obtaining the necessary approval from Structures Division, furnish the Structures Divis ion a reproducible design file. The Department will pay the Contractor for the precast box based on the price bid for the quantity of the items in the cast -in-place structure it replaces. Manufacture the precast reinforced box sections in accordance with Departmental procedures. For fill heights greater than those shown in the standard box culvert drawings for cast -in-place concrete box sections or other non -standard 604.03 501 designs, the Contractor may submit for consideration a value engineering change proposal in accordance with 104.11.
604.03 Classification, Proportioning and Quality Assurance of Concrete
A.Classification and Proportioni ng
1.Classification and Design Parameters
a.Design and Production Parameters . Proportion the concrete based on a pre -determined minimum cementitious content, and a water-cement ratio that does not exceed the maximum shown in Table 604.03 -1. Below this limit, adjust the quantity of water to meet the slump requirements. The fine a ggregate shall not exceed 44% by volume calculation of the total aggregate . For slip formed Class A concrete incorporated into parapets and median barriers , the maximum percent by volume of fine aggregate shall not exceed 46% . Document m ixture adjustment s, for moisture corrections, on the daily report. Ensure that the a djusted mix complies with all the performance criteria specified in Table 604.03 -1. 604.03 502 Table 604.03-1: Composition of Various Classes of Concrete Class of Concrete Min 28-Day Compressive Strength (psi) Min Cement Content (pound per cubic yard) Maximum Water/Cement Ratio (pound/pound) Air Content % (Design + production tolerance) Slump (inches) A 3,000 564 0.45 6 + 2 3 + 1 (1) D, DS (2, 3) 4,000 620 0.40 7 (3) 8 max (4) L (3, 5) 4,000 620 0.40 7 (3) 8 max (4) S (Seal) 3,000 682 0.47 6 + 2 6 + 2 X (6)
1.For slip forming, the slump shall range from 0 to 3 inches.
2.Use Class D concrete in all bridge decks except box and slab type structures unless otherwise shown on the Plans. Use Class DS concrete in bridge decks with polish - resistant aggregate described in 903.03 and 903.24.
3.Design Class D , Class DS, and Class L concrete at 7% air content . Acceptance range for pumping and other methods of placement is 4.5 -7.5%. Sampling will be at the truck chute.
4.Water reducing admixtures are acceptable; however, do not exceed the maximum water/cement ratio in order to achieve the required slump.
5.The unit weight of air dried Class L concrete (lightweight concrete) shall not exceed 115 pounds per cubic foot as determined according to ASTM C567.
6.Plan specific requirements Include chemical admixtures in the concrete mixture based on the ambient air temperature and expected weather conditions. If using a Type A, F, or G water reducer, then the allowable slump shall be a maximum of 8 inches. Admixtures to be incorporated into the concrete shall be compatible and incorporated into the concre te in accordance with the manufacturer’s recommendations. Concrete mixtures utilizing multiple admixture manufacturers shall prove compatibility in accordance with the Departmental procedures . Do not use fine aggregate manufactured from limestone or other polishing aggregates in concrete to be used as a riding surface in traffic lanes. 604.03 503 b. Self-Consolidating Concrete (SCC) Design and Production Parameters Proportion the concrete based on a pre -determined minimum cementitious content, and a water -cement ratio t hat does not exceed the maximum shown in Table 604.03 -2. The fine aggregate shall not exceed 50% by volume calculation of the total aggregate volume. Maximum size of coarse aggregate shall not exceed a No. 67 stone. The Contractor may elect to use SCC a s an alternate/option in replacement of Class A concrete. Document mixture adjustments, for moisture corrections, on the daily concrete report. Ensure that the adjusted mix complies with all the performance criteria specified in Table 604.03 -2. Table 604 .03-2: Composition of Self -Consolidating Concrete Class of Concrete Min 28-Day Compressive Strength (psi) Min Cement Content (pound per cubic yard) Maximum Water/Cement Ratio (pound/pound) Air Content % (Design + production tolerance) Slump Flow (inches) SCC (2,3,4,5) 3,000(1) 564 0.45 6 + 2 26 + 5 SH-SCC (2,3,4,5,6) 4,500 620 0.45 6 + 2 26 + 5
1.Or as shown on the Plans or approved shop drawings.
2.Acceptance range for the T50 test in accordance with ASTM C1611 shall be between 2 -7 seconds.
3.Passing ability in accordance with ASTM C1621 shall be equal to or less than 2 inches for acceptance.
4.Visual Stability Index (VSI) shall not exceed 1 as per ASTM C1611 for acceptance.
5.Static segregatio n as measured by ASTM C1610 shall not exceed 20%.
6.Air Content may be reduced if placed under water or underground if approved by the Engineer. Include chemical admixtures in the self -consolidating concrete mixture based on the ambient air temperature and expected weather conditions. Approved viscosity modifying admixtures (VMA) may be used as part of the chemical admixtures if they are shown in the approved mixture design. Dosage rates for any admixtures incorporated into the concrete shall be stated during the mix design submittal process. All 604.03 504 admixtures shall be compatible and incorporated into the concrete in accordance with the manufacturer’s recommendations. Concrete mixtures utilizing multiple admixture manufacturers shall prove com patibility in accordance with the Departmental procedures.
c.Class X and High Early Strength When the Plans for structural or pavement repairs, or other type work, require high early strength concrete , a Class X design approval is required. The Contractor may use Type I , Type IL, or Type III cement. If Type I or Type IL cement is used, the minimum cement content shall be 714 pounds per cubic yard . If Type III cement is used, the minimum cement content shall be 620 pounds per cubic yard . The Contractor ma y substitute h igh early strength concrete, meeting these requirements, for Class A concrete when approved in writing by the Engineer at no additional cost to the Department . When electing to use high early strength con crete, use the same source and gradation of fine and coarse aggregates as that specified for the concrete being substituted.
2.Mix Design Submittal. Submit, for approval, the proposed design in accordance with Departmental procedures at least 14 days prior to use. Develop the design using saturated surface dry aggregate weights. The design shall be prepared in an approved testing laboratory by a TDOT Certified Concrete Mix Design Technician or a Professional Engineer licensed by the State of Tennessee . The TDOT Certified Concrete Mix Design Technician or Professional Engineer licensed by the State of Tennessee shall certify that the information co ntained on the design submittal is correct and is the result of information gained from the actual trial batch. Build trial batches for design no more than 90 days before submitting the design. The trial batch shall produce an average compressive strength to indicate that the specified 28 -day strength can be obtained in the field. Make all strength determinations using equipment meeting the requirements of, and in the manner prescribed by, AASHTO T 22. The design shall provide concrete of the strength s pecified in all applicable Special Provisions, Plans, and Specifications. The approved mix design will expire at the end of each calendar year or if it does not meet the minimum 28-day 604.03 505 strength requirements. Assume responsibility for all costs of concrete design, preparation, and submittal. Submit a complete concrete mix design using the current template in accordance with Departmental procedures. Self-consolidating concrete (Classes SCC, SH -SCC, and P-SCC) shall be verified prior to placement either at the ready mix , precast, or prestressed facility. The concrete producer shall perform a trial batch verification of the submitted design in the presence of Regional Materials and Tests. The trial batch will ensure that all batched quantities and target ad mixture dosage rates are acceptable and meet specification prior to design approval. All quantities and identified admixture target dosage rates shall meet the tolerances specified in 604.11. Instead of the above design submittal, an existing design may b e submitted for approval provided the design has been approved by the Department within the current calendar year. The approval of this design submittal will not relieve the Contractor of the responsibility of providing concrete meeting the requirements o f these Specifications. A temporary design may be submitted, on the Department’s template, for approval once compressive strength test results meet or exceed the 28 -day strength requirement (as determined by the Plans, Specifications, or Standard Drawings ). The temporary design will be reissued for the calendar year once acceptable 28 -day compressive strength data is submitted. If proposing to use materials or admixtures from sources other than those shown on the approved design a new mix design approval shall be developed in accordance with Departmental procedures. Concrete shall not be placed until the new design is approved.
3.Partial Cement Replacement with Fly Ash or Slag Cement. Do not use concrete with fly ash or slag cement as a partial cement replacement in concrete when high early strength is specified. Only use fly ash or slag cement as a partial cement replacement of Type I or Type IL Portland cement. When choosing to replace a portion of Type I or Type IL cement with fly ash or slag cement, ensure that the following requirements will be met before producing any concrete: 604.03 506 1. Store fly ash or slag cement in silos separate from each other and separate from the hydraulic cement.
2.Add the fly ash or slag cement to the concrete using methods and equipment that are approved by the Engineer and capable of uniformly distributing the materials throughout the mix.
3.The fly ash or slag cement may be weighed cumulatively in the weigh hopper with the cement, provided the cement is added first. The temperature of the fly ash or the slag cement shall not exceed 160 F at the time of introduction to the mix. When designing Portland cement concrete with Type I or Type IL cement modified by the addition of fly ash and/or slag cement, meet the maximum cement replacement rates (by weight) and minimum substitution ratios (by weight) specified in Table 604.03-3 for the applicable type of modifier . Table 604.03-3: Type I or Type IL Cement Modified by Fly Ash or Slag Cement Modifier Maximum Cement Replacement Rate % (by weight) Minimum Modifier Cement Substitution Rates (by weight) Slag Cement (Grade 100 or 120) 35.0 1:1 Class “F” Fly Ash 25.0 1:1 Class “C” Fly Ash 25.0 1:1 The Contractor may use t ernary cement itious mixtures (mixtures with Portland cement, slag cement, and fly ash) for Class A , Class D, and Class DS c oncrete provided that the minimum Portland cement content is 50%. The maximum amount of fly ash substitution in a ternary cementitious mixture shall be 20%. The Department will allow Type IS cement with ternary cementitious mixtures. When using a Type IS cement, do not use any additional slag cement as a partial replacement for the hydraulic cement. The Department will allow a maximum of 20% fly ash as a partial hydraulic cement replacement in Class A concrete using only Type IS cement. 604.03 507 B. Quality Control and Acceptance of Concrete Determine and m easure the batch quantities of all ingredients (including all water and specified or approved admixtures) for all concrete produced for the Project, and to mix, deliver, and place the concrete so that the concrete meets the requirements of these Specifi cations. The Contractor may withhold some of the water from the mix at the facility provided the delivery ticket indicates the amount of water withheld. If a portion of the water is withheld at the facility, the Contractor may add additional water at the wo rk site provided the design water -cementitious material ratio of the mix is not exceeded. The minimum size of a batch shall be 2.5 cubic yards. Provide qualified technicians to perform sampling, testing, and inspection for process control. A TDOT Certifie d Concrete Plant Quality Control Tech nician shall provide process control of the concrete at the facility. This technician shall be present at the facility during al l batching operations for the Project and shall have the primary responsibility during pro duction of performing process control. A TDOT Certified Concrete Field Testing Technician or ACI equivalent shall provide process control of the concrete at the placement site and shall be present during all concrete placement. For placement of concrete for minor structures as noted in 604.03.B, a TDOT Certified Field Testing Technician or ACI equivalent is not required unless process controls or acceptance testing are performed in accordance with Departmental procedures. Provide the necessary equipment to perform process control at the plant and at the placement site during times of concrete placement. The concrete producer shall develop for the Engineer’s approval and maintain at the plant a plant -specific Process Control Plan that shall apply to all Department contracts for the calendar year. Communicate all changes made to the Process Control Plan during the year to the Regional Materials Supervisor. Develop for the Engineer’s approval a placement site Process Control Plan stating the procedures fo r sampling, testing, and inspection of the concrete. Maintain a record of all tests and inspections performed at the facility and placement site. Provide these documents to the Engineer upon completion of the Project for inclusion in the Project records. Keep records current and make them available to the Engineer for review at any time. 604.03 508 For process control, perform the following as a minimum:
1.Test to determine aggregate gradations (AASHTO T 27 with AASHTO T 11 when required). Conduct a combined belt gradation before work starts and at least daily to verify consistency if using a dynamic, multi -aggregate feed system.
2.Inspect the stockpiles to ensure they remain uncontaminated and unsegregated. Maintain a current aggregate quality report at the plant.
3.Calibrate the weighing systems, aggregate feed flow rate and weigh bridges, water meters, and admixture dispensing systems before starting production.
4.Ensure accurate weighing or flow rate of the aggregates and cement, the proper metering of water and admixtures, and the quality of water.
5.Ensure mixing equipment is in proper working condition and the proper mixing speeds and revolutions are controlled as required.
6.Adjust mix proportions due to actual moisture content of both coarse and f ine aggregates, with moisture content determined according to AASHTO T 255. If using a dynamic aggregate weighing system, multi -aggregate proportioning adjustments are to be made by using an in -bin moisture sensor.
7.Conduct slump (AASHTO T 119) or slump flow (ASTM C1611) and air tests (AASHTO T 152).
8.Conduct yield tests (AASHTO T 121). If yield varies more than plus or minus 2% from that shown on the design, stop all batching operations until the problem has been identified and corrected or a new concrete design has been obtained.
9.Prepare quality control cylinders and early break cylinders for compression tests performed according AASHTO T 22.
10.Conduct tests for concrete and ambient air temperatures. 604.03 509 11. Provide a daily re port to the Engineer that identifies the date, Contract and Project, Item number(s), batch weights, moisture corrections, admixtures, slump, air content, temperatures, and similar pertinent information.
12.A concrete delivery ticket shall accompany each load to the placement site. The ticket shall include as a minimum the following:
a.Date
b.Contract number
c.County
d.Class of concrete
e.Approved TDOT concrete mix design number
f.Number of cubic yards
g.Load number
h.Truck number
i.Maximum wate r allowed by design
j.Total water added at the plant
k.Maximum water allowed to be added on the project
l.Water-Cementitious material ratio
m.Number of revolutions at mixing speed at plant
n.Time loaded
o.Actual and target batch weights of each comp onent including each aggregate, chemical admixture and mineral admixture used . Include the difference (%) between the actual batch weights and the target weights.
p.Signature of producer’s TDOT Certified Concrete Plant Quality Control Technician The concrete delivery ticket shall be delivered to the Engineer at the site of the Work. Loads that do not carry such information or do not arrive in satisfactory condition shall not be used. Make, cure, and transport all early break cylinders in accordance with
604.15 C, and deliver to the regional laboratory or other established
satellite laboratories for testing. Make all early break cylinders for self - consolidating concrete according to AS TM C1758, and deliver to the regional laboratory or other established satellite laboratories for testing. The Department or its representative will be responsible for performing all acceptance tests. A TDOT Con crete Field Testing Technician or ACI equivalent will sample and test in accordance with Departmental 604.04 510 procedures. The Department will also be responsible for properly curing and transporting all acceptance cylin ders according to AASHTO T 23. The Department will perform all independent assurance sampling and testing. All sampling and testing for accept ance and independent assurance will be at the frequencies established in Departmental procedures. The Department will determine the time and locati on for obtaining all acceptance and independent assurance samples. Provide cylinder molds, a wheelbarrow, and a level site to perform testing. Provide a secure location for the initial curing of the conc rete acceptance cylinders as specified in 722.09. In addition, the Department will require a n approved concrete design for minor structures. The Contractor may use p re-approved, pre -packaged concrete mixtures listed in the Department’s QPL 15 for these applications if the quanti ty does not exceed 2 cubic yards per day, in which case n o design will be required. If the quantity exceeds 2 cubic yards, prior approval must be obtained from the Engineer prior to placement. All pre-packaged concrete mixtures are required to be mixed in a mechanical concrete mixing machine and in accordance with manufacturer’s recommendations. The following are considered minor structures. See each Section for additional details: 611 Manholes, catch basins, inlets, and pi pe end walls 701 Cement concrete sidewalks, driveways and median pavement 702 Cement concrete curb, gutter, and combined curb and gutter 703 Cement concrete ditch paving 705 Guard rail 707 Fences 709 Rip-rap slope paving 713 Highway signing 714 Roadway and structure lighting EQUIPMENT
604.04 Equipment
Obtain the Engineer’s approval as to the design, capacity, and mechanical condition of equipment and tools used to handle materials and perform the 604.04 511 work. Have the equipment on the jobsite sufficiently ahead of the start of construction operations to be examined and approved by the Engineer. Use equipment and construction processes that have sufficient capacity to accomplish the maximum continuous concrete placement , as governed by the construction joints shown on the Plans or as directed by the Engineer.
A.Batching Plant , Multi-Aggregate Feed System, and Equipment
1.General. The batching plant shall include bins, weighing hoppers, or belt feeds with weigh bridges and load cells, and scales. If using cement in bulk, include a bin, hopper, and separate scale for cement. Provide adequate means for cement cut off checks. Ensure that the weighing hoppers are properly sealed and vente d to preclude dusting during operation. Provide adequate means to sample the cement stored in the bulk cement as specified in Departmental procedures. All producers of concrete shall be on the Department’s Producer List and be actively certified by the National Ready Mixed Concrete Association (NRMCA) Plant Certification Program.
2.Bins and Hoppers . Provide bins with adequate separate compartments for fine aggregates, each size of coarse aggregate, and cement in the batching plant. Ensure that each compartment discharges efficiently and freely into the weighing hopper. Provide controls so that as the quantity desired in the weighing hopper is being approached, the material may be added slowly and shut off with precision. Provide a port or other opening for removing overloaded material from the hopper. Provide weighing hoppers that are constructe d to eliminate accumulations of tare materials and to discharge fully without jarring the scales. Ensure that the partitions between compartments, both in bins and in hoppers, are sufficiently ample to prevent spilling under any working conditions. For multi-aggregate feed systems, provide bins as noted with variable size openings and variable speed belts. Each bin must have a calibrated moisture sensor to adjust aggregate feed flow rates. Assure consistent, uninterrupted aggregate flow and consistent be lt speeds once aggregate feed system is calibrated.
3.Scales. Provide scales of the beam type, springless, dial type or load cell type to weigh aggregates, cement, and pozzolans. Scales shall be accurate within 0.5% throughout t he range of use. Scale dial 604.04 512 faces or digital readouts are to be graduated to indicate loads of 0.1% or less of scale capacity. When using beam type scales, provide an indicator such as a “tell - tale” dial to inform the operator that the required load in th e weighing hopper is being approached. The “tell -tale” device on weighing beams shall clearly indicate the critical position. Poises shall be designed so that they cannot be easily removed from the beam and can be held firmly in place. Ensure that the w eigh beams and “tell-tale” device are in full view of the operator while charging the hopper and that the operator has convenient access to all controls. Inspect and check the scales as often as the Engineer deems necessary to assure their continued accura cy. Scales shall be calibrated by a certified scale company every 6 months. For multi-aggregate feed systems, provide a dual idler weight bridge with load cells to accurately weigh the actual aggregate flow rate.
B.Mixers
1.General. The Contractor may mix concrete at the site of construction or at a central point or wholly or in part in truck mixers. Each mixer shall have attached in a prominent place a manufacturer’s plate showing the capacity of the drum, in terms of mixing and agitating capacity, and the speed of rotation of the mixing drum or blades for both mixing and agitation. Mixers shall be capable of combining the aggregates, cement, water and admixtures, when specified, into a thoroughly mixed and uniform mass wit hin the specified mixing period. They shall have sufficient capacity to comply with minimum production requirements. Equip mixers with an approved device for accurately measuring water within a range of error of not more than 1%. Provide an accurately ca librated and easily read indicator to show the amount of water used in each batch. All mixers shall have blade wear indicators. Repair the pick -up and throw-over blades in the drum or drums once the blade wear reaches the blade wear indicator or when hole s are worn through the blades. 604.04 513 Place the top of the blade wear indicator at 90% of the total height of the radial part of the blade. Retain at the jobsite or central plant a copy of the manufacturer’s design showing dimensions and arrangements of blades. The blade wear indicator shall be a minimum of ¼ inch thick steel, 2 inches wide by 6 inches long.
2.Mixers at Site of Construction. In addition to the above requirements, mixers at the site of construction, unless otherwise stipulated, shall also meet 105.17 and shall be capable of discharging and distributing the mix without segregation.
3.Truck Mixers and Truck Agitators. Truck mixers shall be certified by the National Ready Mix Concrete Association (NRMCA) Delivery Vehicle Certification Program Option A or Option B. Each truck shall display the NRMCA certification card. Ensure that truck mixers used for mixing and hauling concrete, as well as the truck agitators used for hauling central -mixed concrete, meet all the applica ble requirements specified in 604.04.B.1 . Truck mixers shall have a manufacturer’s plate indicating the various uses for which the equipment is designed, the gross volume of the drum, and the minimum and maximum speed of rot ation of the drum or blades for charging, mixing and agitating. Equip truck mixers with an approved device for recording the number of revolutions of the drum or blades. Provide a mple and satisfactory equipment for conveying concrete from the mixer to final position in the forms. Use c losed chutes or pipes when concrete is to be dumped or dropped for a distance greater than 5 feet. Where steep slopes are required, equip the chute s with baffle boards , or use chutes in short lengths that will allow the direction of movement to be reversed. Use vibrators of an approved type and operate them under load at the rate recommended by the manufacturer and approved by the Engineer. When plac ing concrete by pumping, do not use aluminum conduit. Do not pour any concrete for bridge decks or slabs above grade before verifying the availability and operability of all necessary equipment approved by the Engineer, including finishing machines, contin uous water source or portable tanks, water distribution equipment, two work bridges, vibrators, sprayers, a 12 -foot straightedge, and appropriate backup items. 604.04 514 Provide at every concrete deck pour a portable, cold fogger capable of changing humidity and coo ling air above fresh concrete. The fogger shall be designed to provide a maximum VMD (volume mean diameter) of 15 microns, and a throw distance of 60 feet.
C.Volumetric Continuous Mixers Produce concrete specified in Table 604.03 -1 in accordance with 604.03, in a volumetric continuous mixing plant provided that the manufacturer’s equipment meets the tolerance requirements of Table 604.11 -1. Use a volumetric continuous mixing plant that co nforms to the following:
1.The unit shall be equipped with:
a.Calibrated proportioning devices for each ingredient added to the concrete mix and perform mixing by a continuous auger and/or paddles.
b.Equipped with proportioning controls that may be set and secured for different materials and mixes.
c.A working recording meter that is visible at all times and furnishes a ticket printout with the calibrated measurement of the mix being produced.
d.Separate bins and gate openings for each type of material, including a watertight storage bin for cement. Cover the aggregate bins with tarpaulins or by other approved methods when required.
2.The unit shall have a stamped plate from the Volumetric Mixer Manufacturers Bureau (VMMB) stating the equipment conforms to ASTM C685. The plate shall be attached in a prominent place and indicate the gross volume of the transportation unit.
3.The volumetric mixing plant shall be operated and calibrated by a Volumetric Mixer Operator certified by VMMB and holds a TDOT Concrete Field Testi ng Technician Certification or equivalent. Perform the calibration of gate settings according to the manufacturer’s recommendations for the mix design to be used before starting work. The calibration procedure shall account for the moisture content of th e aggregates. The yield shall be maintained within a tolerance of plus or minus 1% and verified, in 604.04 515 the presence of the Engineer, using a minimum of a 0.25 cubic yard container every 500 cubic yards or a minimum of once per week. Recalibrations shall be necessary when indicated by the yield checks, every 6 months, every 2,500 cubic yards, or at any time the Engineer deems necessary to ensure proper proportioning of the materials.
4.Tests for aggregate moisture contents and gradations shall be performed by a TDOT Concrete Plant Quality Control Technician or a TDOT Aggregate Certified Testing Technician.
5.Concrete mix design submittal shall be in accordance with
604.03 A.2 .
If the mixer fails to discharge a uniform mix at any time, production of concrete shall halt until any problems are corrected and approved by the Engineer. A volumetric continuous mixing plant shall provide a concrete delivery ticket for each load. The ticket shall include as a minimum the following:
a.Date
b.Contract number
c.County
d.Class of concrete
e.Approved TDOT concrete mix design number
f.Number of cubic yards
g.Truck number
h.Maximum water allowed by design
i.Total water added
j.Water-cementitious materials ratio
k.Time discharged
l.Signature of producer’s VMMB Certified Volumetric Mixer Operator Provide the concrete delivery ticket to the Inspector at the site of the Work. Loads that do not carry such information or do not arrive in satisfactory condition shall not be used. 604.05 516 CONSTRUCTION REQUIREMENTS
604.05 Forms
A.Construction Forms shall be mortar -tight and sufficiently rigid to prevent distortion due to the pressure of the concrete and other stresses incidental to the construction operations, including vibration. C onstruct and maintain forms to prevent the opening of joints due to shrinkage of the lumber. Build the forms true to line and grade. Hold the forms in place with studs or uprights, and waling, which shall be sufficiently and substantially braced and tied. Cut off and cap all forms and studding with not less than a 2 x 4-inch piece. Chamfer all exposed edges with ¾-inch material, unless otherwise specified. All chamfer strips shall be straight, of uniform width, and dressed. Remove wood devices used to separate forms before placing concrete within 4 inches of such devices.
B.Form Lumber Dress form lumber for all exposed concrete surfaces on at least one side and two edges, and construct to produce mortar -tight joints and smooth, even concrete surfaces. The Contractor may use plywood forms, or forms face -lined with plywood, masonite, or other approved similar material, provided the plywood forms and form linings are substantial, of uniform thickness, and are mortar -tight when in position.
C.Metal Ties Construct metal ties or anchorages within the forms to allow their removal to a depth of at least 1 inch from the face without damaging the concrete. If wire ties are permitted, cut the wires back at least ¼ inch 604.05 517 from the surface of the concrete, and ensu re that the surface is left sound, smooth, even, and uniform in color.
D.Walls Provide sufficient openings at intervals along the bottom of wall forms to allow thorough cleaning before concrete placement. Close such openings before placing concrete in the f orms.
E.Surface Treatment Before placing reinforcement, treat all forms to prevent the adherence of concrete. Treat forms, which are not provided with a special treatment, with an approved oil. Do not use any material that will adhere to or discolor the concrete.
F.Metal Forms Ensure that metal forms comply with all requirements for forms, as regards design, mortar tightness, filleted corners, beveled projections, bracing, alignment, removal, reuse, and oiling. Construct forms using metal of sufficient thickness to ensure that the forms will remain true to shape. Countersink all bolt heads on the face forming the concrete surface. Use clamps, pins, or other connecting devices designed to ho ld the forms rigidly together and to allow removal without damaging the concrete. Do not use metal forms that do not present a smooth surface or do not line up properly. Keep metal forms free from rust, grease, or other foreign matter.
G.Permanent Steel Br idge Deck Forms The Contractor may use permanent steel forms to construct bridge deck forms for concrete deck slabs of bridges. Do not use permanent steel bridge deck forms for the overhang portions of the slab. The following criteria shall govern the design of permanent steel bridge deck forms:
1.Design the steel forms 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 not exceed 0.725 of the specified minimum yield 604.05 518 strength of the material furnished, or 36,000 pounds per square inch, whichever is less .
2.Deflection under the weight of the forms, the plastic concrete , and reinforcement sh all not exceed 1/180 of the form span or ½ inch, whichever is less, but in no case shall this loading be less than 120 pounds per square foot total. The permissible form camber shall be based on the actual dead load condition. Do not use camber to compen sate for deflection in excess of the se limits. Laminations may be used to satisfy design criteria.
3.If the design span of the form sheets is less than the clear distance between top girder flanges minus 2 inches, include the design for the support syste m with the shop drawing submittal.
4.Compute p hysical design properties according to the American Iron and Steel Institute Specification for the Design of Cold Formed Steel Structural Members, latest published edition.
5.Provide a minimum concrete cover of 1 inch over all reinforcement, both transverse and longitudinal in the bottom mat.
6.Maintain t he plan dimensions of both layers of primary deck reinforcement from the top surface of the concrete deck.
7.Do not consider p ermanent steel bridge deck for m as lateral bracing for compression flanges of supporting structural members.
8.Do not use p ermanent steel bridge deck forms in panels where open longitudinal deck joints are located between stringers.
9.Submit the f abricator’s shop and erection drawings to the Engineer of Structures for approval. These drawings shall indicate the grade of steel, the physical and section properties for all permanent steel bridge deck form sheets , and the method of attaching the forms and form supports to the main structural members. All drawings shall be stamped by a Professional Engineer licensed in the State of Tennessee. R eview and approval of shop drawings by the Engineer of Structures will extend only to general details of forms and atta chments. As this forming system is not an integral load -carrying member of the 604.05 519 completed slab, the Engineer of Structures will not review the design. The Contractor shall assume sole responsibility for ensuring the safe design of the metal decking system and its installation.
10.Do not rest f orm sheets directly on the top of the stringer or floor beam flanges. Securely fasten each flute of each sheet to form supports and to have a minimum bearing length of 1 inch at each end.
11.Place form supports in direct contact with the flange of either the stringers or floor beams. Make all attachments by bolts, clips, or other approved means. Do not weld form supports to main structural members.
12.If permanently exposed form metal contains areas of damaged galvanized coating, thoroughly clean and wire brush such areas, and apply two coats of zinc -oxide powder primer, Federal Specification TT -P-641d, Type II, no color added, to the satisfaction of the Engineer. It is not necessary to touch up minor heat discol oration in areas of welds.
13.Locate transverse construction joints at the bottom of a flute , and field drill ¼-inch weep holes at not more than 12 in ches on center along the line of the joint.
14.Ensure that the concrete is properly vibrated to avoid honeycomb and voids at construction joints, expansion joints, valleys, and ends of form sheets. Obtain the Engineer’s approval of p ouring sequences, procedures , and mixes. Do not use calcium chloride or other admixture s containing chloride salts in the con crete placed on permanent steel bridge deck forms.
15.After the deck concrete has been in place for a minimum period of 2 days, test the concrete for soundness and bonding of the forms by sounding with a hammer. If this procedure reveals areas of doubtfu l soundness, remove the forms from such areas for visual inspection after the pour has attained adequate strength.
16.Where sections of the forms are removed, the Engineer will not require the Contractor to replace the forms, but the Contractor 604.05 520 shall repa ir the adjacent metal forms and supports to present a neat appearance and to ensure their satisfactory retention. Remove or repair a ll unsatisfactory concrete as directed by the Engineer. Repair, at no cost to the Department, all damage to the concrete, reinforcing steel , or both caused by the inspection process.
17.As permanent steel deck forms are not a structural component of the bridge or deck system, the Contractor shall assume responsibility for determining the structu ral adequacy of the deck forms to support the wet concrete and specified construction load allowance. It is also the Contractor’s responsibility to verify that the deck system meets all the requirements set forth in this section.
18.The Department will not pay for, and will instead consider incidental to the forming system, all overruns in deck concrete attributable to deflections or distortions in the deck form .
H.Special Forming Systems The use of precast bridge deck panels eliminat es the bottom reinforcing mat used in cast -in-place bridge decks; therefore, it is not possible to make all of the ties needed to maintain the rigidity of the reinforcing mat, deck form, and girder system. To enhance the stability of this system during co nstruction, provide additional reinforcing, ties, temporary erection diaphragms, and permanent diaphragms as shown on the Plans and as specified below. Include the cost associated with these requirements in the unit price of items bid .
1.Tie the strands projecting from the ends of deck panels to the upper mat of reinforcing steel at 2 -foot maximum spacing. Tie the upper mat to projecting shear reinforcement or stud shear connectors at maximum 2 -foot spacing along the beam.
2.For precast, prestressed I -beams and bulb-tee beams, construct additional permanent diaphragms or additional temporary erection diaphragms as shown on the Plans between all girders at substructures and at intermediate points such that the spacing between diaphragms does not exceed th at shown on the Plans.
3.For precast , prestressed box beams, construct additional permanent diaphragms or additional temporary erection 604.05 521 diaphragms as shown on the Plans between all girders at substructures and at intermediate points such that the spacing between diaphragms does not exceed that shown on the Plans.
4.For prestressed I -beams, bulb -tee beams, and box beams, form and pour the bottom 15 inches of diaphragms at bents as soon as possible after setting beams, using Class A concrete (3,000 psi). Pour the remaining portion of the diaphragms at substructures concurrently with the bridge deck. Provide temporary erection diaphragms as shown on the Plans at the ends of girders where the end diaphragms are to be poured concurrently with the bridge deck. The Contractor may also submit alternate temporary diaphragm details to the Engineer for approval.
5.For prestressed beams , do not pour any part of i ntegral abutment backwalls prior to, or concurrently with, placement of the slab until at least half of the slab in the end span has been poured . Pour a minimum of the top 12 in ches of the abutment backwall concurrently with the slab. Provide t emporary erection diaphragms as shown on the Plans at the ends of girders. The Contractor may also submit alterna te temporary diaphragm details to the Engineer for approval. Support the beams to prevent damage due to twisting or overturning during all phases of construction.
6.Place form supports for precast bridge deck panels in direct contact with the flange of the girders or beams . Make all attachments by bolts, clips , or other approved means. Do not weld form supports to the main structural members. To request use of a special forming system not specifically authorized in this Specification, submit the design and calculations to the Engineer of Structures for review and approval.
I.Global Stability of Exterior Girders during Slab Overhang Pours Ensure the stability of the exterior girder(s) against twisting, overturning, and web buckling during slab po uring operations. This may require supplemental bracing. When the width of the slab overhang exceeds the depth of the exterior girder, submit details and design calculations for the cantilever support (including deflections caused by the mechanical screed) to the Engineer for approval. 604.06 522 J. Other Considerations If the deck slab thickness is increased more than 1 -1/2 inches due to the use of permanent deck forms or precast deck panels, redesign the girders for the entire change in thickness , and bear a ll costs incidental to the increased depth of slab thickness and girder redesign , if required. All bridge beams and girders shall be erected and the grade of the roadway established on the bridge before forming is started for the bridge deck, unless otherwise shown on the Plans or approved by the Engineer.
604.06 Falsework
Support falsework, used to support the forms and concrete for concrete structures, on sills resting on rigid foundations composed of solid rock, piles driven until the bearing capacity of each pile is sufficient to support the required loading, or earth borne footings as specified in this Subsection 604.06. The Department will only allow earth borne footings when, in the Engineer’s opinion, the soil ca n adequately support the superimposed loads and the following conditions are met:
1.Only use s pread footings on stable ground that is capable of supporting the superimposed load.
2.Grade and maintain t he site to prevent ponding of water, or erosion of soil in the proximity of the spread footings.
3.Design and construct the falsework system to not exceed the bearing capacity of the soil, and in no case to exceed 3,000 pounds per square foot .
4.Design and construct t he footings t o carry the superimposed loads.
5.Construct a ll footings on a level plane. The bearing value of piles will be calculated according to the formulas given in 606.14. Design and construct the falsework to support the required loading without distortion or settlement of the forms. 604.07 523 Place “tell -tales” to allow for observation of the amount of falsework settlement at locations designated by the Engineer. The Engineer may require the Contractor to submit detailed falsework plans, together with a soils report, design calculations, and other information necessary for a thorough review. The Contractor is responsible for the design and construction of the falsework system and shall repair, or remove and replace, as directed and at no cost to the Department, all concrete, other material, or portions of the structure that are damaged or destroyed due to failure of the falsework. Have all plans for falsework and formwork for cast -in-place structures over navigable waters or pedestr ian or vehicular traffic stamped by a Professional Engineer licensed in the State of Tennessee. Before placing any superstructure concrete, furnish to the Engineer a certification similar to the following: CERTIFICATION I hereby certify that the plans for falsework and formwork on (Structure Identification) have been prepared by me in accordance with accepted structural engineering practice. I further certify that said falsework has been erected in full compliance with said plans. , P.E. Tennes see License Number
604.07 Camber
Construct structures of any type or size to a permanent camber only when shown on the Plans. Provide sufficient camber in the falsework and forms for each span to allow for the tightening of joints in the forms and supporting falsework. 604.08 524 604.08 Reinforcement
A.General All reinforcement shall consist of deformed steel bars meeting the requirements of ASTM A615 Grade 60, unless other wise shown on the Plans or directed by the Engineer. Use standard CRSI hook details unless otherwise specified. Reinforcing steel designated with the suffix E shall be epoxy coated as specified in 907.01. Deformed steel bars shall have a net area at all sections equivalent to that of plain round or square bars of the corresponding nominal size. Steel wire fabric, meeting 907.03, may be furnished in rolls or sheets.
B.Protection of Material Store reinforcing steel above the ground surface on platforms, skids, or other supports located outside the scope of the active construction operations . Protect the reinforcing steel from physical damage, rust, and other surface deterioration. Remove all brush and weeds from the storage area i mmediately before storing reinforcing steel in the area.
C.Bending Cold bend reinforcing steel, where indicated, to the forms and dimensions shown on the Plans. Unless otherwise indicated, ensure that all bends are in one plane. Uncoated bars of ¾ inch or less that have only hooks or a single bend may be bent in the fie ld, provided satisfactory equipment for proper and accurate work is used, and provided the bending is accomplished true to form and dimensions without damage to the bars. Perform all other bending in the shop before shipment.
D.Substitution The Contractor may substitute bars of different sizes from those shown on the Plans only with the Engineer’s written permission. If substitution is allowed, comply with the following:
1.Do not reduce t he total area of steel in any 1 foot in each direction. 604.08 525 2. For cast-in-place concrete, the clear distance between parallel bars in a layer shall not be less than 1.5 bar diameters, 1.5 times the maximum size of the coarse aggregate, or 1 -1/2 inches.
3.Where positive or negative reinforc ement is placed in two or more layers, place bars in the upper layers directly above those in the bottom layer with the clear distance between layers not less than 1 inch.
4.Clear distance limitation between bars shall also apply to the clear distance bet ween a contact lap splice and adjacent splices or bars. Limit groups of parallel reinforcing bars bundled in contact to act as a unit to four in any one bundle. Limit bars larger than No. 11 to two in any one bundle in beams. Locate bundled bars within stirrups or ties. Individual bars in a bundle cut off within the span of a member shall terminate at different points with at least 40 bar diameters stagger. Where spacing limitations are based on bar diameter, treat a unit of bundled bars as a single bar of a diameter derived from the equivalent total area.
5.In walls and slabs, space the primary flexural reinforcement no farther apart than 1.5 times the wall or slab thickness, or 18 inches.
E.Splicing Furnish all reinforcement in the f ull length shown on the Plans, unless otherwise approved in writing by the Engineer. The Contractor may splice temperature reinforcement at no additional cost to the Department. Splicing may occur once per bar in the end sections of box and slab type culverts that are on a skew other than 90 degrees and in box and slab type culverts that require no contraction joints due to their length. In end sections of 90 degree skewed structures and in interior sections of all box and slab type culverts, furnish temperature reinforcement in the full length required, with no splices. Do not make any splices, unless shown on the Plans or authorized by the Engineer of Structures. Do not splice tension reinforcement at points of maximu m stress. Rigidly clamp the members at all splices with at least two approved metal clips located approximately 3 inches from the ends of the bars and bolted around them, or secure with wire in a manner satisfactory to the Engineer. 604.08 526 Splice steel shapes on ly as shown on the Plans. Splice steel fabric by overlapping the sheets by not less than 12 inches, matching at least three transverse members, and by securely wiring the overlapped sections in a manner satisfactory to the Engineer.
F.Placing and Fastening Before placing reinforcing steel, thoroughly clean it of mill scale, rust, dirt, paint, oil, or other foreign substances or coating of any character that will reduce the bond. Once in -place, if reinforcement becomes dirty, rusty, or spattered with mortar t hat dries before concrete is placed around it, thoroughly clean such reinforcement, or the part affected, before covering it with concrete. Accurately place and firmly hold in position all reinforcement as shown on the Plans or as directed by the Engineer. Fasten uncoated steel bars together with metal clips or wire at each intersection. Fasten coated steel bars with coated wire ties or coated clips. Where spacing is less than 1 foot in each direction, fasten alternate intersections. Securely space all reinforcing steel from the forms and between adjacent reinforcement with approved metal spacers, concrete blocks, or other approved devices or methods, except only use metal spacers in slabs of bridges and top slabs of box type structures. Where possible, arrange spacer devices so that their use cannot be detected in the completed structure . Mix concrete for spacer block construction in the same proportions as that used in the concrete mixture. Construct the blocks to be rectangular in shape with uniform surfaces and with no dimension greater than the depth required for proper spacing from the forms or between adjacent reinforcement. Do not use gravel, brick, or wooden blocks. Before depositing concrete, ensure that all reinforcing steel in the section of the concrete pour is accurately and securely placed and the Engineer has approved the placement. Do not disturb the spacers during concrete placement. All dimensions relating to the spacing or cover of reinforcing bars are to the centers of the bars or the clear distance respectively, unless otherwise indicated. Tolerances for placement shall be plus or minus ½ inches for spacing and minus 1/8 inch or plus 3/8 inch for cover. 604.09 527 604.09 Drainage and Weep Holes Construct drainage opening s and weep holes using materials in the manner and at the locations shown on the Plans or established by the Engineer. Place ports or vents for equalizing hydrostatic pressure, when required, as directed by the Engineer. Where structures are to be backfil led, protect weep holes or openings by placing a wire basket, with dimensions of 1 foot x 1 foot x 1 foot and filled with coarse aggregate of size 7, 8, 57, 67, 68, or 78, immediately over or behind the holes or openings, as directed by the Engineer. Afte r all finished grading is complete, clean weep holes of all dirt and debris, and ensure that they are free draining.
604.10 Placing Pipes, Conduits, Anchors, Casting, and other
Appurtenances As directed by the Engineer, place, during construction, all pip es, conduits, anchors, castings, bolts, plates, grillages, and other appurtenances that are necessary or desirable to be placed in the concrete of a structure, whether shown on the Plans or not. Unless otherwise specified, assume that such pipes and condu its will be delivered to the site of the structure by the Department or by other parties for whose use the pipes and conduits are intended. The Department will not pay for placing such pipes, conduits, and other appurtenances; however, it will not make any deductions for the volume of concrete displaced by those items.
604.11 Handling, Measuring, and Batching Materials
Ensure that the batch plant site, layout, equipment, and provisions for transporting material will provide a continuous supply of material to the work. Build and maintain aggregate stockpiles as specified in 903.20. A concrete delivery ticket shall accompany each load to the placement site and shall include, as a minimum, the information specified in 604.03.B.12 . Handle and transport aggregates from stockpiles or other sources to the batching plant in such a manner as to maintai n a uniform grading of the material. Do not use aggregates that have become segregated or mixed with earth or foreign material. Stockpile or bin all aggregates produced or handled by hydraulic methods at least 12 hours before being batched to allow for drainage. Consider rail shipment requiring more than 12 hours as adequate 604.11 528 binning only if the car bodies allow free drainage. If the aggregates contain high or non -uniform moisture content, the Engineer may require storage or stockpile periods in excess o f 12 hours, or sprinkling of aggregate to achieve uniform moisture content. Separately weigh the fine aggregate and each size of coarse aggregate into the hopper or hoppers in the respective amounts set by the Engineer. Measure cement by weight, using se parate scales and hoppers. The scales shall be equipped with a device to indicate positively the complete discharge of the batch of cement into the batch box or container. The Contractor may use batching plants equipped to proportion aggregates and bulk c ement by weight by means of automatic and interlocked proportioning devices of the approved type. Individual materials shall be batched within the tolerances specified in Table
604.11 1.
Table 604.11 -1: Concrete Batching Tolerances Size Tolerance Cementitious Materials -1% to +4% Aggregates ± 1.5% When mixing is at the site of construction, transport aggregates from the batching plant to the mixer in batch boxes, vehicle bodies, or other containers of adequate capacity and construction to properly carry the volume required. Ensure that partitions s eparating batches are adequate and effective to prevent spilling from one compartment to another while in transit or being dumped. For bulk cement, use a suitable method of handling the cement, from weighing hopper to transporting container, for transpor tation to the mixer, with chute, boot, or other approved device, to prevent loss of cement and to provide positive assurance of the actual presence in each batch of the entire amount specified. Transport bulk cement to the mixer in weathe rproof compartments carrying the full amount of cement required for the batch. The Contractor may transport cement in original shipping packages on top of the aggregates, with each batch containing the proportion required by the job mix. 604.11 529 Deliver batches t o the mixer separate and intact. Dump each batch into the mixer without loss of any material, and when more than one batch is carried on the truck, without spilling of material from one batch compartment to another. Water shall be measured by either volum e or weight. The accuracy of measuring the water shall be within a range of error of not more than 1%. Unless otherwise allowed, calibrated tanks for measuring water shall include an auxiliary tank from which the measuring tank shall be filled. The measuring tank shall be equipped with an outside tap and valve to check the setting unless other means are provided for readily and accurately determining the amount of water in the tank. The volume of the auxiliary tank shall be at least equal to that of the measuring tank. Use chemical admixtures as specified in 604.03, and add them to the mix using the manner and method recommended by the manufacturer, subject to the Engineer’s approval. Add air -entraining agents to the mix using an approved procedure and an approved dispenser to ensure accurate proportioning of the agent. Measure all admixtures to an accuracy of plus or minus 3%. When using lightweight aggregates, uniformly pre -saturate the aggregates and allow to drain. At time of use, ensure that the a ggregates are in a saturated surface dry condition to minimize water absorption. When placing concrete during hot weather, take appropriate measures to reduce the hazards of increased rate of cement hydration and high concrete temperatures. The temperature of the concrete at point of discharge shall not exceed 90 F. Reduce the temperature of the concrete using one or any combination of the following methods:
1.Sprinkle coarse aggregate stockpiles to distribute the water evenly and to prevent moisture variation within the stockpile.
2.Use crushed or chipped ice as a portion of the mixing water, or use water cooled by refrigeration or other means. If using ice, substitute it on a pound for pound basis for water and ensure that it is completely melted before the concrete is discharged from the mixer.
3.The Contractor may employ other means as approved by the Engineer. 604.12 530 Unless otherwise specified, to use additives or admixtures, submit a revised mix design for the Engineer’s review and approval . Unless specifically provided in the Contract, the Department will consider the furnishing and use of approved additives or admixtures and the other precautions necessary to provide satisfactory concrete and concrete products to be incidental to the furnishing and placement of the concrete, and the Contractor shall bear all additional costs and risks. Do not mix different types of cement, and do not use them alternately. Where it is necessary for the color of the concrete to be uniform, only those cements that will produce similar color in concrete may be used alternately.
604.12 Mixing Limitations
Stop mixing concrete in time to allow finishing to be completed in daylight hours, unless an adequate and approved artificial lighting system is provided and operated. Unless authorized in writing by the Engineer, discontinue mixing and concreting operations when falling air temperature in the shade and away from artificial heat reaches 40 F. Do not resume operations until rising ai r temperature in the shade and away from artificial heat reaches 35 F. When concreting at temperatures above 35 F, heat or cool the aggregates or water as necessary before placing in the mixer so that the temperature of the resultant mixture will be no less than 50 F and no more than 90 F at the time of placement. If heating is required, use an apparatus that will heat the mass uniformly and that will prevent the possible occurrence of overheated areas that might damage the concrete. Do not use frozen aggregates in the concrete. When concreting is authorized at temperatures of 35 F or less, heat the water or the aggregates or both to no less than 70 F and no more than 150 F. Ensure that the temperature of the heated mixture is no less than 60 F and no more than 100 F at the time of placement on the road.
604.13 Mixing Concrete
The Contractor may mix concrete in a central -mix plant or in truck mixers. The mixer shall be of an approved type and capacity, and shall comply with the applicable requirements of 604.04.B. Clean mixers at suitable intervals 604.13 531 to prevent buildup of hardened concrete that could affect the mixer’s capacity and mixing ability. Dump the batch into the drum so that a portion of the mixing water enters in advance of the cement and aggregates. Measure mixing time from the time all materials, except water, are in the drum. Ensure that the flow of water is uniform, and that all wate r is in the drum by the end of the first 15 seconds of the mixing period. Keep the throat of the drum free of accumulations that may restrict the flow of materials into the drum. When mixed in a central mixing plant, ensure that the mixing time is no less than 60 seconds and no more than 90 seconds. Mixing time ends when the discharge chute opens. Include transfer time in multiple drum mixers in the mixing time. Remove the contents of an individua l mixer before a succeeding batch is emptied therein. Operate the mixer at the speed recommended by the manufacturer. Dispose of concrete mixed less than the specified time at no additional cost to the Department. Do not operate mixers for central mix plants at a capacity greater than the manufacturer’s guaranteed mixing capacity. Transport mixed concrete from the central mixing plant in truck mixers or truck agitators. Truck mixers and truck agita tors used to transport concrete from a central mixing plant and truck mixers used to mix concrete in transit from a central batching plant shall meet all applicable requirements of
604.04 B.3 , and in addition, the mixing spee d and agitating speed shall be
those recommended by the manufacturer of the mixer, and the total revolutions at mixing speed shall be within the range of 70 to 100 for drum mixers. Operate truck mixers and truck agitators within the capacity recommended by the manufacturer. When the concrete is mixed and transported in truck mixers; no more than 90 minutes shall elapse from when the water is added to the mix until the concrete is deposited in place at the site of the work . When the ambient air temperature exceeds 90 F, no more than 60 minutes shall elapse for concrete placed in bridge decks. Do not retemper concrete by adding water or by other means. However, the Contractor may withhold a portion of the mixing water or chemical admixtures from transit mixers and add at the work site if all requirements of the approved concrete mix design is met, provided th e delivery ticket indicates the amount of water withheld. The total amount of water in the mix shall not exceed the maximum in the approved concrete mix design. To 604.14 532 achieve additional slump, use a water reducing admixture. If water, air entrainers, or ch emical admixtures are added at the placement site, mix the concrete a minimum of 30 revolutions at mixing speed after making the additions. Do not use concrete that is not within the specified slump limits, air content limits, temperature limits, or time limits at the time of placement. For the items of construction identified in 604.03.B, the Contractor may perform concrete mixing using mobile volumetric measuring and mixing equipment as specified in 604.04.
604.14 Consistency of Concrete
The slump of the concrete when measured according to AASHTO T 119 shall meet 604.03.A.1.a. The slump flow of self -consolidating concrete when measured according to ASTM C1611 shall meet 604.03.A.1.b .
604.15 Compres sive Strength Tests of Concrete
A.General The Engineer will determine concrete streng th by tests performed during the progress of the work and will use these tests to determine the strength of the concrete for acceptance and pay purposes. The frequency of testing will be as specified in the sampling and testing schedule of Departmental p rocedures. The frequency of testing for compressive strength to determine when forms may be removed, or when a structure may be put into service, shall be as requested by the Contractor or as deemed necessary by the Engineer in accordance with 604.15.C .
B.Concrete Acceptance Cylinders The Department will test t he specimens for compressive strength according to AASHTO T 22. Provide t he necessary concrete for making test specimens and adequate curing and storage facilities at no additional cost to the Depart ment . Concrete cylinders submitted for testing beyond 28 days shall comply with the design strength requirements specified in 604.03 or the Plans. 604.15 533 If the acceptance cylinders fail to meet the specified strengths, the Contractor must provid e QC data from co mpanion cylinders that meet or exceed the required strength , and TDOT Materials and Test shall perform a nondestructive test using a Swiss Hammer on the concrete to prove required strength is achieved , and then the Contractor may drill core samples from th e hardened concrete as verification of concrete strength instead of using the concrete cylinders . Companion cylinders shall be made from the same sample as the acceptance cylinders. If these requirements are met, the Contractor may then elect to drill a maximum of three concrete core samples per set of cylinders from the hardened concrete. The Contractor shall o btain the cores in accordance with Departmental procedures. O btaining the concrete cores and repairing the concrete core holes shall be at no co st to the Department . The compressive strength of concrete cores submitted beyond 28 -days from the placement date will be adjusted using the following equation: A = [[4.1 + (0.85 * B)]/B] * C Where: A = the Calculated Result of the Compressive Strength of the Concrete at 28 days (psi) B = the Age of the Concrete (days) C = the Compressive Strength Result of the Concrete Core (psi) The Engineer will not accept concrete cylinders and cores submitted for testing beyond 56 days. The average compressive stren gth of the two cores taken to represent the failing concrete cylinders will be considered to be the acceptance strength of record for the in -place concrete. In accordance with 604.31 , the Engineer will accept at a reduced pay c oncrete that meet s the required strengths specified in 604.03 or the Plans for the respective class. All concrete used shall undergo acceptance testing. The Department will determine the method to formally accept in-place concrete that is represented by acceptance cylinders that have been lost, damaged, or destroyed. These methods may include coring or non -destructive testing. 604.16 534 C. Early Break Cylinders Make and cure all test specimens according to AASHTO T 23, and the applicable procedures therein defined for Field Cured Specimens , unless otherwise specified by the Engineer. The Department will test the specimens for compressive strength according to AASHTO T 22. Provide the necessary concrete for making test specime ns at no additional charge to the Department. Cylinders shall be representative of the concrete placed and shall be cured in the same manner and method as the placed concrete. Specimens shall be protected from the elements in the same manner as the formed work. If specimens are to be used for determining when a structure is capable of being put into service the specimens should be removed from the molds at the time of removal of the form work.
604.16 Placing Concrete
A.General Do not place concrete until the Engineer has checked and approved forms and reinforcing steel. Ensure that the forms are clean of all debris and are kept wet immediately before concrete is placed. Obtain the Engineer’s approval of the method and sequence o f placing concrete. Unless otherwise allowed, place all concrete in daylight. Do not start placing concrete in any portion of a structure unless it can be entirely completed in daylight. When the placing of concrete is allowed during other than daylight hours, provide and operate an adequate and approved artificial lighting system. Plans for nighttime operations, including adequate lighting, shall be acceptable to the Engineer. Use tools of an approved type to thoroughly work concrete during placing ope rations. 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. If the forms show bulging or settlement whi le concrete is being placed, stop placing until a correction has been made. Construct T -beam girders, slabs, arch rings, and all horizontal sections, except curbs and sidewalks, monolithically and continuously, unless otherwise allowed by the Engineer. 604.16 535 Construct curbs and sidewalks after the bridge deck is completed, unless otherwise shown on the Plans. After initial set and before final set of the concrete, do not jar forms or place any strain on the ends of projecting reinforcement. Drive piles no closer than 20 feet to footings that are less than 7 days old and to foundations supporting concrete that is less than 7 days old. Unless otherwise specified, before placing a bridge deck overlay of Class D, Class DS, or Class L concrete, machine scarify the su rface to be covered to a minimum depth of 1 inch. In areas inaccessible to machine scarifying, and in areas of spalling where steel reinforcement is exposed, remove deteriorated concrete using hand tools or other methods approved by the Engineer. After s carifying, clean the deck of all deleterious material. Do not allow traffic on the scarified deck. Take care to avoid contaminating the surface of the bridge deck after scarification. Remove all contaminants from the deck to the Engineer’s satisfaction b efore placing the concrete overlay. When placing concrete in bridge decks when the rate of moisture evaporation may be excessive as determined by the Engineer , comply with the following additional requirements .
1.Do not start any concrete deck pour s until the mandatory Bridge Deck Construction Pre -pour Meeting is conducted and all pertinent con siderations covered by the Pre -Pour Check List are resolved.
2.Protect t he concrete to prevent rapid drying due to high temperature, low humidity, high winds , or combinations thereof. Do not place any concrete when the rate of moisture evaporation from the freshly placed concrete exceeds 0.2 pounds per square foot per hour as determined by Figure
604.16 1 below. Provide the Engineer appropriate measuring
devices meeting industry standards to establish the temperature of the concrete and ambient air, relative humidity , and wind velocity adjacent to the concrete surface. 604.16 Figure 604.16 -1: ACI nomograph for estimating rate of evaporation of surface moisture fr om concrete
3.If data collected during the 24 hours prior to the pour, or predictions from the National Weather Service indicate that the moisture evaporation rate of 0.2 pounds per square foot per hour may be exceeded, limit concrete placement to hours w hen the evaporation rate is less than 0.2 pounds per square foot per hour. An exception to this requirement would be if the 604.16 537 Contractor demonstrates to the Engineer’s satisfaction before the pour that protection can be provided, or other actions taken, to maintain an acceptable moisture evaporation rate. Schedule placement of bridge deck concrete accordingly. Notwithstanding all precautions, if during concrete placement , the evaporation rate of 0.2 pounds per square foot per hour is exceeded, terminate th e pour as directed by the Engineer. In hot weather (generally 90oF and greater or as determined by the Engineer), apply a certified dry fog with a maximum volume mean diameter (VMD) of 15 microns with a throw distance of 60 feet above the concrete surface during placement and finishing operations. Furnish a certification to the Engineer verifying the VMD. In addition, immediately before placing the concrete, cool the forms and reinforcing steel to 90 °F or less by using a fine spray of water, leaving no puddles or pockets of water. Sprinkle t rucks or keep them in the shade when not being unloaded to help reduce the temperature of the concrete. Use one of the four following methods at the discharge point when pumping concrete:
1.A metal loop consisting of four 90 -degree elbows shall be placed in the line just before the rubber discharge hose.
2.A minimum of 10 feet of line lying horizontally just before the discharge point.
3.A rubber discharge hose configured into a “j” shape or loop, either of which prevents a loss in the pressure of the discharge line.
4.A rubber discharge hose, 10 to 12 feet in length, that reduces in diameter from 5 to 4 in ches over its len gth.
B.Railings and Curbing When constructing curb, take care in installing railing steel or anchoring devices. Do not construct concrete railings on any structure until the falsework has been struck. 604.16 538 C. Chutes and Troughs Place concrete to prevent segregation of materials and displacement of reinforcement. Keep all chutes, troughs, and pipes clean and free from coatings of hardened concrete by thoroughly flushing with water after each run. Discharge the water used for flushing clear of the concrete already in place. Take care to fill each part of the form by depositing the concrete as near final position as possible. Work the coarse aggregate back from the forms and around the reinforcement without displacing the bars.
D.Vibrating Unless otherwise directed, compact the concrete with suitable mechanical vibrators operating within the concrete. When required, in addition to vibrating, also hand spade with suitable tools to ensure proper and adequate compaction. Manipulate vibrators to wo rk the concrete thoroughly around the reinforcement and embedded fixtures and into corners and angles of the forms. Do not use vibrators to cause concrete to flow or run into position. The vibration at any point shall be of sufficient duration to accompl ish compaction without causing segregation. Have at least one additional stand -by vibrating unit available for all individual pours in excess of 10 cubic yards.
E.Joints Do not produce a featheredge at construc tion joints. Do not construct transverse or longitudinal joints through spans , unless otherwise specified. Placement of bridge deck concrete between specified transverse construction joints shall be continuous unless otherwise approved in writing by the Engineer. If the Contractor fails to maintain a rate of placement of 20 feet per hour in the longitudinal di rection as specified in 604.22, or if, in the Engineer’s judgment, placement is interrupted unduly because of failure or repositioning of equipment or any other cause, the Engineer may direct that all placement be stopped and a 604.17 539 transverse construction joint be formed in the deck as shown on the Plans or as directed by the Engineer. Clean layers completing a day ’s work, or placed just before temporarily discontinuing operations, of all laitance or other objectionable material as soon as the surface has become sufficiently firm to retain its form. To construct box culverts 6 feet or less in height, the Contractor may construct the side walls and top slab as a monolith. When using this method of construction, construct any necessary construction joints vertical and at right angles to the axis of the culvert. To construct box culverts more than 6 feet in height, place the concrete in the walls and allow to set at least 4 hours before constructing the top slab. Leave appropriate keys i n the side walls for anchoring the top slabs. Unless otherwise shown on the Plans, transverse contraction joints in box culverts shall be plain butt joints and longitudinal reinforcement shall not extend across the joint. Space contraction joints at inter vals of 30 to 40 feet. Predetermine the location of joints, and when practicable, place them at changes in the box section. Locate these joints parallel to the main reinforcing steel in the slab and not necessarily perpendicular to the axis of the box or slab type culverts.
604.17 Bonding Construction Joints
Where dowels, reinforcing bars, or other adequate ties are not shown on the Plans, form keys of a directed size by constructing projections above the concrete and monolith ically with the concrete. In resuming work, draw the forms tightly against the face of the concrete. Thoroughly clean the entire surface of the concrete to be bonded and roughen with a steel tool. Before proceeding with concreting, soak the surface with clean water.
604.18 Depositing Concrete Under Water
Do not deposit any concrete, except for cofferdam seals and drilled shafts, under water. Perform the work specified in 204.10 to prepare foundations before placing concrete foundation seals. It is necessary to inspect foundations for seal concrete. Provide an experienced diver equipped with a diving suit, two -way telephonic and other appurtenant equipment necessary for performing underwater inspections. 604.18 540 Place concrete for seals only in still water and ensure that the cofferdams or cribs meet the requirements specified in 204.09. Regulate the method of depositing concrete to maint ain the surface of the concrete as nearly horizontal as practicable throughout the operation. Place the concrete in a compact mass in its final position using a tremie , unless otherwise approved by the Engineer. Do not disturb the concrete after depositing, and do not expose it to the action of water before final setting. Obtain cores for each seal footing. However, the Engineer will waive the inspection and coring of the seal footing if the seal footing is founded on piles and the encas ed piling projects above the seal footing and embeds into the structural footing a minimum length as shown on the Plans. Obtain four cores, size N, as described by the Diamond Core Drill Association , or larger, representing 80% of the depth of the seal fo oting as directed by the Engineer unless otherwise noted on the Plans. Should the cores or other inspection indicate an inferior seal, perform corrective measures at no cost to the Department. Unless otherwise noted, consider the costs for coring the sea l to be incidental to other work items. Mix all concrete deposited under water in the proportions designated for Class S concrete. No additional compensation will be allowed for the additional cement. Regulate the consistency of concrete to prevent segregation of material during placement. Place underwater concrete continuously until the work is completed. The tremie shall consist of a metal tube and suitable hopper of sufficient strength to withstan d the stresses to which it is subjected. The tube shall have a minimum inside diameter of not less than 10 inches and shall be constructed in sections having flanged couplings fitted with gaskets. Support the tremie to allow free movement of the discharg e end over the entire top surface of the work and to allow the tremie to be rapidly lowered when necessary to reduce or stop the flow of concrete. Equip the lower or discharge end of the tremie with a suitable valve or device that shall be tightly closed while the tremie is being charged and lowered into position, and that can be fully opened in the lower position. Keep the discharge end closed until the tube is filled with concrete to prevent water from entering. Induce concrete flow by raising the tremie, but always keep the discharge end in the deposited concrete. After removal of cofferdam sheeting, provide an underwater diver and camera to perform a tactile inspection of the concrete seal exposed faces and provide a video to document the condition o f the exposed seal footing surfaces. 604.19 541 604.19 Removal of Forms and Falsework The Contractor may remove forms for ornamental work, railings, parapets, columns, and vertical surfaces that do not carry loads with in 12 to 48 hours, unless otherwise directed by the Engineer. In cold, damp, or freezing weather, all vertical forms shall remain in place until the concrete has set sufficiently to withstand damage when the forms are removed. When removing forms, take c are not to mar the concrete surface or to subject it to any undue pressure. Remove or cut, as specified in 604.05.C, projecting wires or other metal devices used for holding forms in place and that pass through the body of the concrete. Fill the holes or depressions thus made, and all other holes, depressions, and small voids that show upon the removal of the forms, with cement mortar mixed in the same proportions as that used in the body of the concrete being repaired. The Contractor may release and remove falsework and supports under concrete structures when the following conditions are met :
1.Representative specimens of the concrete, made and cured in accordance with 604.15.C, attain a compressive strength of 3,000 pounds pe r square inch.
2.The concrete has been in place a minimum of 7 days, not counting days of 24 hours each in which the temperature falls below 40 F, or 21 calendar days, whichever occurs first. After the above conditions have been met, the Contractor ma y proceed with placing further concrete pours or erecting precast or fabricated members. Allow other loadings as specified in 604.28. For continuous concrete girder or slab units, do not release or remove the falsework and suppo rts from any span in the continuous unit until the concrete in all spans has been placed a sufficient length of time to meet all requirements for the removal of falsework and supports specified above.
604.20 Defective Concrete
Remove and replace defective concrete upon discovery . If the surface of the concrete is bulged, uneven or has honeycombing that cannot be repaired satisfactorily, remove and replace the entire section or unit. The extent of the removal shall be as determined by the Engineer. 604.21 542 Concrete having an acceptance compressive strength less than the minimum specified shall be removed, disposed of, and replaced by the Contractor at no cost to the Department, unless specifically authorize d by the Engineer, in writing, to be included in the permanent work. Remove and dispose of nonconforming concrete in a manner that will not damage existing construction or other facilities and property. The Engineer may allow concrete that fails to meet the strength specified to remain in the permanent construction, provided the durability is acceptable ; but the Department will pay for this concrete at a reduced price. The Department will adjust the bid price for concrete that fails to meet the specified strength, but is considered structurally adequate for inclusion in the permanent construction, in accordance with 604.31. The Department will base any adjustment in bid price due to low strength concrete on the acceptance compr essive strength of record for the concrete , as determined in accordance with 604.15.
604.21 Finishing Concrete Surfaces
Unless otherwise authorized, finish the surface of the concrete immediately after removing forms. Give all concrete surfaces a Class I finish. Give the following surfaces of all structures a Class II or Applied Texture Finish: roadway face and top of curbs, vertical outside face of curb overhang or sidewalks slab, bottom surface of s lab overhang, bridge railings, barrier railings, all vertical surfaces of the superstructure of dual bridges exposed to view from either structure, and all surfaces of retaining walls, wing walls, and end walls that are visible from passing vehicles. Give all surfaces of structures over a highway or another structure exposed to general view a Class II or Applied Texture Finish. Such surfaces, in addition to those specified above, will usually include all parapets, copings, columns, piers, bents, sides and ends of caps, the outside of all fascia beams, the ends of arch rings, outer surfaces of spandrel walls, the exposed surfaces of wing walls, and the faces of abutments. The Plans will show if additional surfaces, other than those already indicated, are to receive a Class II or Applied Texture Finish. If an Applied Texture Finish is used, the color of the finish shall be similar to Mountain Gray, Federal Specification No. 36440, Federal Color Standard 595b , except that the inside face and the top of the parapet or rail shall be White, Federal Specification No. 37886 . Submit a color sample to the Engineer for approval. 604.21 543 Do not combine the Class II and Applied Texture Finish. If the Plans show an Applied Texture Finish, do not use a Class II finish. The Plans may show other finish classes for designated surfaces.
A.Class I, Ordinary Surface Finish Begin finishing as soon as forms are removed. Remove all fins and irregular projections from surfaces that are to be exposed or waterproofed. On all surfaces, e nsure that the cavities produced by form ties and all other holes, honeycomb spots, broken corners or edges, and other defects, are thoroughly cleaned, saturated with water, and carefully pointed and trued with a mortar of cement and fine aggregate mixed i n the proportions used in the class of the concrete being finished. Mortar used in pointing shall not be more than 30 minutes old. Leave all construction and expansion joints in the completed work carefully tooled and free of all mortar and concrete. Le ave the joint filler exposed for its full length with clean and true edges. On all surfaces that cannot be repaired to the Engineer’s satisfaction, rub as specified for a Class II finish.
B.Class II, Rubbed Finish Complete a Class I finish. Saturate the con crete with water. Ensure that sufficient time has elapsed before the wetting down to allow the mortar used in the pointing to thoroughly set. Rub the surfaces to be finished with a wetted wooden block or a medium coarse carborundum stone. Do not use the carborundum stone until the concrete has hardened to the state where the sand will grind, rather than ravel or roll. Continue rubbing until all form marks, projections, and irregularities have been removed, all voids filled, and a uniform surface has bee n obtained. Leave the paste produced by this rubbing in place. The Engineer will not allow a brush finish or painting with grout. After all concrete above the surface being finished has been cast, obtain the final finish by rubbing with a fine carborundu m stone and water. Continue this rubbing until the entire surface is of a smooth texture and uniform color. After the final rubbing is completed and the surface has dried, rub it with burlap to remove loose powder and ensure it is free from all unsound patches, paste, powder, and objectionable marks. 604.21 544 C. Class III, Float Finish For unformed surfaces, except slab surfaces for pavements or bases, achieve a Class III finish 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. Avoid creating concave surfaces. After the concrete has been struck off, thoroughly work the surface and float with a suitable floating tool of wood, canvas, or cork. Before the fin ish has set, remove the surface cement film with a fine brush to produce a fine -grained, smooth but sanded texture.
D.Applied Texture Finish To prepare the surface for a textured finish, first provide a Class 1 Ordinary Surface Finish . Allow the concrete to set for a minimum of 28 days to allow for ample cure time and weathering of curing compounds before applying the textured finish. Pressure wash all surfaces just before application. Remove from surfaces to be coated all efflorescence, flaking, coating, rust, dirt, oil, and other foreign substances. Apply coatings only to surfaces that are free of surface moisture as determined by sight and touch. Shield and mask surfaces that are not to receive a Coated Finish. Vee out cracks over 1/8 -inch wide and fill with an approved product from the Department’s QPL. Obtain the Engineer’s approval of the surface preparation immediately before starting the work. Apply the textured finish in the number of coats as recommended by the manufacturer and as posted on the Department’s QPL to achieve a total application rate of 1 gallon per 45 square feet. If using a two -coat system, apply a base coat similar in color to Mountain Gray, Federal Specification No. 36440, when the final coat is White , Federal Specification No. 37886. When the final coat is similar in color to Mountain Gray , Federal Specification No. 36440 , use a base coat of White, Federal Specification No. 37886 . Provide advance notice to the Engineer of the date(s) and time(s) the texture coating is to be a pplied. Apply the textured finish with rollers or brushes to provide a consistent and uniform coverage. As an alternative, the Contractor may spray the textured finish if using a containment system meeting the Engineer’s approval. Regardless of the meth od of application, prevent drippings and overspray from the texturing process or otherwise contain in a manner that will not contaminate the environment. 604.22 545 Submit to the Engineer certification of the following:
1.Brand name,
2.Production batch or lot numbe r,
3.Qualified Products List Evaluation Number,
4.Manufacturers recommended rate of application,
5.Safety Data Sheet,
6.Materials Data Sheet, and
7.Shipping date. Submit a color sample to the Engineer for approval.
604.22 Finishing Slab Surfaces for Pavements or Bases
Use approved mechanical finishing machines to finish bridge floors or top slabs of structures serving as finished pavements or bases. In extreme cases where mechanical finishing machines cannot be used, such as narrow width s due to phase construction, the Engineer may allow hand finishing or other methods. Mechanical finishing machines shall be approved power driven machines, traveling on rails adjusted to conform to the profile of the roadway. Equip the machines with oscil lating or vibrating transverse or longitudinal screeds that may be adjusted to conform to the profile or the required cross -section of the roadway. The screed shall have sufficient strength to retain their shape after adjustment. Pass over each area of t he bridge floor with the finishing machine as many times as necessary to obtain the required profile and cross - section. When using longitudinal screeds, comply with the following restrictions:
1.The span length of the slab section to be poured shall be 70 feet or less.
2.Place sufficient concrete ahead of the strike -off to fully load the beam or girder prior to strike -off.
3.Control the rate of placement to ensure that the concrete will not take its initial set before the entire placement is complete.
4.The slab to be poured shall be in a tangent section. 604.22 546 5. Assume responsibility for damage to the structure caused by using this method. Do not change the sequence of construction, as shown on the Plans, without the Engineer’s written approval. When using the hand method, strike off the bridge floors or slabs with a screed that is parallel to the centerline of the roadway resting on bulkheads or screed strips cut or set to the required cross -section of the roadway. This screed shall have sufficient streng th to retain its shape and a cutting edge that may be adjusted to conform to the profile of the roadway. Screeds shall be of sufficient length to finish the full length of spans 40 feet or less in length. Finish spans over 40 feet in length in two or mor e sections, but no section shall be less than 20 feet in length. Set screed strips or headers to the specified grades, and check and adjust as necessary before the final screeding operation. Work the screed back and forth over the surface until the prope r profile and cross -section is obtained. Maintain a minimum placement rate of 20 feet of deck per hour when placing concrete in a longitudinal direction. For bases, finish the surface by grooving lightly with a wire broom at an angle of 60 degrees with the centerline. Begin all strokes at the center and end at the edge. Finish and texture the surface of bridge approach slabs, bridge decks, and top slabs of other structures serving as roadway pavements by Method 3 below, except Method 1 or 2 may be used whe re shown on the Plans and/or where the design speed of the roadway on which the structure is located is less than 40 miles per hour.
1.Finish the surface by dragging a seamless strip of damp burlap over the full width of the surface. Use a burlap drag co nsisting of sufficient layers of burlap to slightly groove the surface and move it forward with a minimum bow of the lead edge. Keep the drag damp, clean, and free of particles of hardened concrete. When allowed by the Engineer, the Contractor may use a light broom or brush herringbone finish that leaves a texture similar to that obtained by the burlap drag.
2.Finish the surface with a burlap drag as noted in Method 1 above. Then, at an appropriate time during the stiffening of the concrete, form transv erse grooves in the surface so that in the hardened concrete the grooves will be between 0.09 and 0.13 inches in width; between 0.12 and 0.19 inches in depth; and spaced at random 604.23 547 intervals between 0.3 and 1.0 inches. The grooves shall be relatively smooth and uniform. Form the grooves without tearing the surface or bringing pieces of coarse aggregate to the surface, and to drain transversely.
3.Finish the surface with a burlap drag as noted in Method 1 above. Then, after allowing the concrete to cure a s specified in 604.23 and to harden sufficiently to support the necessary equipment, groove the surface transversely using a mechanical saw device that will leave grooves 0.125 inches wide, 0.125 inches deep, and randomly spaced from 0.75 to 1.125 inches apart center to center. Perform any corrective grinding for smoothness before transverse grinding, otherwise it will be necessary to re -groove. Establish positive means for removing grooving residue as specified in
604.27 C.
Terminate the grooves formed by Method 2 or 3 approximately 12 inches from curbs, parapets, barrier walls, and other vertical walls. Include all costs for finishing and texturing in the unit price bid for the concrete being placed. As soon as the surface has set sufficiently to withstand damage when walking on it, and not later than the morning following the placing of the concrete, apply a 12 -foot straightedge and mark all variations exceeding 1/8 inch. Correct and seal such vari ations in the same manner as specified in 604.27.C.
604.23 Curing Concrete
Cure all concrete surfaces as specified below, except those surfaces protected by forms that remain in place 7 days or longer as specified in 604.19. Use curing materials that meet the requirements of 913. Begin curing on unformed surfaces immediately after the water sheen disappears and the surface finish is applied. On formed surfaces, begin curing immediately after removing forms. When the temperature is expected to fall below 35 F, protect th e concrete as specified in 604.24. Cure bridge decks and the top slabs of other structures located above the roadway subgrade elevation by using both the Membrane -Forming Compound Method and the Water Method . Use new burlap for each pour, except burlap may be reused on the same project if it is undamaged and 604.23 548 deemed acceptable by the Engineer. The Contractor may cure all other concrete surfaces by either of the following methods.
A.Membrane -Forming Compound Method Give all surfaces the required surface finish and keep it moist before applying the curing compound. Apply the burlap drag finish on bridge decks, and on the top slabs of other structures that also serve as the roadway surface, as soon as practicable after screeding the s urface, and then immediately apply the membrane curing compound. Apply the curing compound at the manufacturer’s recommended rate. Apply the curing compound under pressure. Only use hand sprays in areas that are inaccessible to pressure equipment. At the time of application of the curing compound, the concrete shall be thoroughly moist but without surface water. At the time of use, ensure that the compound is in a thoroughly mixed condition with the pigment or dye uniformly dispersed thr oughout the vehicle. If the application of the compound results in a streaked or blotchy appearance, take corrective action at once to obtain a well - dispersed mixture of uniform appearance. For concrete surfaces that are not protected by burlap curing co vers, use other means to protect against marring for a period of 5 days from the date of application. Immediately replace membrane coating marred within the 5 -day period on an otherwise unprotected surface.
B.Water Method As soon as possible a fter applying curing compound to bridge decks and to other top slabs located above subgrade elevation, apply either a combination of damp burlap and white polyethylene sheeting or a white, co-polymer coated, absorbent, non -woven synthetic fabric, from a work bridge, taking care not to mar the surface of the deck. The sheeting material shall meet the performance requirements of ASTM C171. Immediately cover a ll other concrete slabs with materials suitable for use with the water cure. After placing the protective cover , immediately apply a mist spray and keep the cover thoroughly wet with a continuously fed soaker hose system for 120 hours. Keep all surfaces other than slabs protected from the sun and wet for a period of at least 72 hours from the beginning of the initial curing period. For finishing , the Contractor may temporarily remove the covering from 604.24 549 curbs, walls, handrails and other surface s requiring a Class II finish, but shall restore t he covering as soon as possible.
604.24 Protection of Concrete in Cold Weather
If, after the concrete has been placed, the ambient temperature is ex pected to drop below 35 F, provide insulation blankets, sufficient canvas, and framework, or other types of housing, to enclose and protect the structure in such a way that the air surrounding the fresh concrete can be maintained at a temperature of at le ast 45 F and the surface temperature of the concrete will not exceed 80 F. Maintain the above conditions for a period of 120 hours after the concrete is placed. Furnish a maximum -minimum thermometer to the Engineer for temperature documentation.
604.25 Painting Metals
Paint, as specified in 603, all exposed surfaces of all metals that are not lubricated or that do not have a bituminous coating, unless otherwise indicated or directed. Clean the sur face of metals having a bituminous coating and treat with two coats of bitumen to present a smooth finished surface that is tough and tenacious when cold but not tacky when warm . The bituminous coating shall have no tendency to scale off . Exposed surfaces , as used above, shall include the inside of cast iron drainpipes or weep holes.
604.26 Waterproofing and Waterstops
Perform waterproofing, where shown on the Plans or directed by the Engineer, as specified in 605. Install waterstops, as specified, as shown on the Plans and in conformity with the requirements of these Specifications. Install waterstops in continuous strips without splices, except that splices will be allowed at changes in direction when necessary to avoid buckling or distortion of the web or flange. Perform all splices of waterstops in accordance with the manufacturer’s recommendations. For polyvinyl chloride waterstops, the heat used shall be sufficient to melt but n ot char the plastic. 604.27 550 Ensure that the waterstops are supported during the progress of work and are properly embedded in the concrete. Work the concrete in the vicinity of the joints to ensure maximum density and imperviousness. Use forms that can be remov ed without damaging the waterstops. Provide suitable guards to protect exposed projecting edges and ends of partially embedded waterstops from mechanical damage.
604.27 Rideability of New or Resurfaced Bridge Decks and Roadway
Approaches
A.General The rideability requirements shall apply to all new or resurfaced bridge decks and roadway approaches. Bridge decks resurfaced with bituminous material shall meet the respective rideabili ty requirements for the bituminous material as specified in 407.18 or in the contract. Set all asphalt paving in e ach 150-foot approach area to grade by using string lines. Set all concrete paving in each 150 -foot approach area to grade by using string l ines or side forms set to grade. Assume responsibility for the final adjustment of the string lines in the approach area. Fabricate and install all expansion joints in accordance with 623, Standard Drawings, and approved shop drawings. Form the recess f or the expansion device to the proper dimensions to allow placement of the expansion device.
B.Rideability Testing After the bridge deck, approach slabs, and roadway pavement tie -ins are completed, the Department will conduct rideability tests using a roadw ay profiler to provide an International Roughness Index (IRI) for each wheel path and Mean IRI (MRI) for overall roughness. A lot is considered each lane for the length of the bridge and 150 feet before and 150 feet after each end of the bridge, unless a shorter distance is specified by the Engineer or shown on the Plans. Each lot shall be tested. Schedule rideability testing at least seven days prior to need. Clean and clear the area to be tested of all obstructions. Wheel paths will be located 3 feet each side of the centerline of each traffic lane. 604.27 551 To determine pavement rideability, the Department will evaluate the pavement using Mean IRI for the lot and IRI for individual continuous 25-foot sections for localized roughness in each wheel path. Mean IRI shall be the average of each wheel path. IRI data shall be calculated per ASTM E1926. Each lot shall have a maximum Mean IRI value of 130 inches per mile. For bridges with a posted speed limit of 45 mph or greate r no individual continuous 25 -foot section shall exceed an IRI of 190 inches per mile in either wheel path, except sections which include an expansion joint. For bridges with a posted speed limit of 40 mph or less, no individual continuous 25 -foot section shall exceed an IRI of 250 inches per mile in either wheel path, except sections which include an expansion joint. For sections with an expansion joint, no individual continuous 25 -foot section shall exceed an IRI of 350 inches per mile in either wheel path.
C.Pay Factor and Required Corrective Action Perform corrective action to reduce the Mean IRI for each lot or IRI for all individual continuous 25 -foot section that fails to meet the requirements specified. Perform corrective action to reduce the Mean IRI for each lot to 130 inches per mile or less. No more than 0.25 inches (two grinding passes) of material shall be removed by corrective diamond grinding without approval of the Engineer. The individual continuous 25 -foot sections with localized rough ness exceeding the limits specified for each wheel path must be corrected regardless of Mean IRI results. A grinding strategy plan is required before any corrective action begins. Submit a copy of the grinding plan to the Engineer at least 5 days prior to starting any work. Perform corrective action, including grinding of bridge decks and approach slabs, removal of pavement tie -ins, resurfacing, and application of sealants, at no additional cost to the Department. Grinding shall be performed by a power dr iven, self-propelled grinding machine that is specifically designed to smooth and texture Portland cement concrete surface using diamond blades. The effective base of the machine shall not be less than 12 feet. The equipment shall be of a size that will cut or plane at least 3 feet wide. The equipment shall be capable 604.28 552 of grinding the surface without causing spalls at cracks, joints, or other locations. Do not use asphalt milling or cold planing machines to perform grinding work on Portland cement concre te bridge deck surfaces. Do not grind Portland cement concrete bridge deck surface within 2.25 inches of reinforcing steel. Establish a positive means for removing grinding and grooving residue. Remove solid residue from pavement surface during the grin ding or grooving operations. Do not allow residue to flow across lanes used by public traffic, into gutters, or drainage facilities. Dispose of residue in a manner that will prevent residue, whether in solid or slurry form, from reaching any waterway in a concentrated state. Perform all corrective action on bridge decks before final surface grooving. Seal all surfaces that are ground with an approved penetrating sealant listed on the QPL. The Department will retest corrected surfaces with the roadway p rofiler to ensure that the IRI does not exceed the maximum requirements. After corrective action is complete, lots that do not meet an MRI of 130 inches per mile or less, a pay adjustment will be assessed by using the following equation. Pay Adjustment = 130-MRI 130 x $9,000
604.28 Loading and Opening to Traffic
Do not allow any traffic, heavy equipment, storage of materials, or other loading on a structure or any part thereof, except as noted in 604.19, until all forms and falsework have been removed and 10 calendar days have elapsed thereafter, unless otherwise noted in the Plans. Construction loads on bridges applied anytime subsequent to the placement of girders shall not exceed 50 pounds per square foot based on a uniform distribution of load. Reconcile loads characterized as non -uniform in nature either by analysis equating the load to an effective uniform load or by the use of timbers or other means approved by Engineer to distribute construction loads. The length of load distribution may be taken as the bridge beam spacing (or slab span between walls for concrete culverts) occurring at the 604.29 553 location of load application. Submit all analysis and supplementary support details required to ensure proper construction load distribution. If concrete is mounded ahead of the screed machi ne during placement of the deck, consider that portion extending above the screed elevation as a construction load. Place construction loads as optimally as reasonable to minimize loads on the structure. When the area occupied by construction loads in an y structure span exceeds 25% of the area of that span, submit a diagram detailing the location, character, sequence, and weight of all construction loads applied to the structure to the Division of Structures for approval. Submit this diagram at least 30 days in advance of the planned operation.
604.29 Final Cleanup
Perform final cleanup as specified in 104.10. COMPENSATION
604.30 Method of Measurement
A.Concrete for Structures The Department will measure c oncrete for concrete structures, unless otherwise specified, by the cubic yard for payment purposes . The volume will be computed from the dimensions shown on the Plans or directed in writing by the Engineer , except for the concrete fillet above fabricated bridge girders. This fillet, as shown on the Plans, is intended to allow for adjustment due to the imprecise methods of predicting camber development of structural members. At the time of construction, the fillet used to compensate for grade changes due to camber development, super -elevation, or other factors beyond the Contractor ’s control will be field measured for payment by profiling of the bridge members. The Department will make no allowances for:
1.Furnishing the material and constructing drainag e openings and weep holes as shown on the Plans or as directed by the Engineer, provided such openings are 6 inches in diameter or less, except that no deduction will be made for such openings in the computation of concrete quantities. Allowance will be made for other openings as indicated. 604.30 554 2. Additional cement used in depositing concrete under water; for use of chemical admixtures , for fillers, sealers, and tar paper used in expansion joints; for dowels or other materials used in bonding construction join ts; for waterstops; and for painting metals.
3.Concrete placed below the foundation elevation shown on the Plans, unless directed by the Engineer. When approved by the Engineer, the Department will measure concrete used for leveling structure footings by the cubic yard using the average end area method or other approved methods. Unless otherwise indicated, the Department will deduct the volume of concrete displaced by pile heads. The Department will make no additional compensatio n for high early strength concrete substituted by the Contractor for other classes of concrete. The unit price for the class of concrete for which the substitution was made shall be full compensation for the concrete. The Department will measure by the square yard any hydro-blasting of the bridge deck performed before placing a bridge deck overlay .
B.Structure Excavation and Foundation Preparation The Department will measure and pay for Structure Excavation, Foundation Preparation and Backfill in accordance with 204, except when the Plans indicate that no payment will be made for excavation and foundation preparation, then the Department will not measure excavation and will consider it incidental to other items of construction. When, under 204.10.A, the Contractor places a foundation seal that is not included in the Plans, the Department will not measure and pay for furnishing the concrete and placing the seal, unless the following requirements and conditions are complied with before placing the foundation seal:
1.Cofferdams in which seals are requested shall have been constructed in strict compliance with 204.09.
2.After investigation, the Engineer determines that conditions have been encountered that make it impracticable to de -water the foundation before placing the footing. 604.30 555 3. The Contractor requests and receives approval for the construction of the seal in writing.
4.The Department and the Contractor exec ute a Change Order to establish a unit price per cubic yard and the method of measurement for the concrete to be used in the seal. When the above conditions have been met, the Department will measure and pay for the Concrete Foundation Seal in accordance w ith the terms of the Change Order.
C.Reinforcement The Department will measure and pay for steel bar reinforcement used in concrete structures, unless otherwise specified, by the pound, as computed from the dimensions shown on the Plans, or directed in writi ng by the Engineer, and the weights specified in Tables 604.30 -1 and
604.30 2.
Table 604.30-1: Steel Bar Reinforcement Bar Designation No. Weight (pounds per foot) 3 0.376 4 0.668 5 1.043 6 1.502 7 2.044 8 2.670 9 3.400 10 4.303 11 5.313 604.31 556 Table 604.30-2: Large Bar Sizes Bar Designation No. Weight (pounds per foot) 14S 7.650 18S 13.600 The bar numbers designate the number of 1/8 of an inch increments in the nominal diameter of the bars. The nominal diameter of a deformed bar is equivalent to the diameter of a plain bar having the same weight per foot as the deformed bar. The Department will make no allowance for any device for splicing, clamping, tying, or positioning the reinforcement.
D.Applied Texture Finish The Department will measure Applied Texture Finish by the square yard of concrete surface treated, as determined in accordance wi th 109.
604.31 Basis of Payment
The Department will pay for accepted quantities at the contract prices as follows: Item Pay Unit Class A Concrete (Description) Cubic Yard Class D Concrete (Description) Cubic Yard Class DS Co ncrete (Description) Cubic Yard Class L Concrete (Description) Cubic Yard Class S Concrete (Description) Cubic Yard Steel Bar Reinforcement Pound Epoxy Coated Reinforcing Pound Scarifying Square Yard Applied Texture Finish Square Yard Hydro-demolition Square Yard The Department will pay for the concrete fillet above fabricated bridge girders as bridge deck concrete with the quantities based on the fillet required for a conventional deck forming system and measured as specified in
604.30 A. The Department will not pay for i ncreases in the fillet depth
needed to accommodate the Contractor ’s chosen deck forming system (e.g. 604.31 557 precast deck panels) and will consider this increase to be incidental to other items bid. The Department will pay for accepted quantities of leveling concrete at 40% of the price bid for the concrete used in the footing as approved by the Engineer. If the Contractor does not meet the surface rideability requirements specified in 604.27, the Department will make deduction s in monies due to the Contractor on a lump sum basis . When field conditions result in the construction of a different type of box culvert or box bridge from that shown on the Plans (box type to slab type or vice versa) , the Department will increase the respective bid price per cubic yard for Class A concrete by 15% for constructing a slab type instead of box type and will decrease the bid price by 13% for constructing box type instead of slab type. The Department will not adjust the Steel Bar Reinforcement unit bid price for the change in box culvert or box b ridge type. Where concrete does not meet the specified strength but is allowed to be included in the permanent construction as specified in 604.20 or cores fail to meet the strengths specified in 604.15, the Department will use the following equation to determine percent payment of contract bid price. PP = 100 – (3 × Ds) Where: PP = Percent Payment Ds = Percent Below Specified Strength Ds = [(Specified Strength -Actual Strength) Specified Strength] × 100 The Department will base the percent p ayment on the unit price of the item as bid, i.e., volume [ cubic yards ], length [ feet], each, or other des ignated bid unit. Payment of the calculated percentage includes cost of incidental items such as reinforcing steel when included in the price bid for the i tem. Defective concrete greater than 25% below specified strength may remain in place at no cost to the Department if approved by the Department of Structures , or the Contractor may remove and replace the defective concrete . 606.01 558 SECTION 606 – PILING
606.01 Description ................................ ................................ ................... 558
606.02 Classification ................................ ................................ ................ 559
606.03 Materials ................................ ................................ ...................... 559
606.04 Equipment ................................ ................................ .................... 559
606.05 Preliminary Work ................................ ................................ ......... 562
606.06 Precast Concrete Piles ................................ ................................ .. 562
606.07 Cast -in-Place Concrete Piles ................................ ........................ 564
606.08 Test Piles ................................ ................................ ...................... 565
606.09 Calibration Tests ................................ ................................ .......... 568
606.10 Order Lists for Piles ................................ ................................ ..... 568
606.11 Storage and Handling ................................ ................................ ... 569
606.12 Driving Piles ................................ ................................ ................ 569
606.13 Bearing Value and Penetration ................................ ..................... 571
606.14 Determination of Bearing Value ................................ .................. 571
606.15 Inspection of Shells for Cast -in-Place Piling ............................... 573
606.16 Extensions and Splices ................................ ................................ . 573
606.17 Cutoffs and Treatment of Pile Heads ................................ ........... 574
606.18 Conditioning of Treated Timber Piles after Driving .................... 574
606.19 Painting Steel Piles and Steel Shells ................................ ............ 574
606.20 Final Cleanup ................................ ................................ ............... 574
606.21 Method of Measurement ................................ .............................. 575
606.22 Basis of Payment ................................ ................................ .......... 577
DESCRIPTION
606.01 Description
This work consists of furnishing and driving or placing piling. This w ork also includes the furnishing and driving of test piling and production piling and conducting load tests, when shown on the Plans or included in the Contract.
Source: Tennessee Standard Specifications for Road and Bridge Construction, 2021 Edition. Pages 507–566 of 1,072.