521 CONTINUOUSLY REINFORCED PORTLAND CEMENT CONCRETE PAVEMENT
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- Construct continuously reinforced Portland cement concrete pavement on a prepared subgrade.
- Refer to 520.02 and the following:
- Reinforcement. Section 908 for reinforcement, load transfer assemblies, tie bars, deformed steel bars, and longitudinal tie devices, except that all materials shall be epoxy coated. Select the type of reinforcement from one of the following:
- (a) Deformed steel bar mats as specified in 908.07. Use No. 5, Grade 60 longitudinal bars, and No. 4, Grade 60 transverse bars.
- (b) Loose deformed steel bars as specified in 908.01. Use No. 5, Grade 60 longitudinal bars with a length of at least 40 ft, and No. 4, Grade 60 transverse bars.
- (c) Welded deformed steel wire fabric as specified in 908.06.
- Refer to 520.03 except as follows.
- 521.03.01 Placing Reinforcement. Preset the reinforcement on chairs or chair bars with the transverse members placed below the longitudinal members. Place the longitudinal bars within the tolerances specified.
- Before placing the concrete, remove rust, mud, oil, or other detrimental coatings. Place the mat and fabric reinforcement flat and free from distortions. Furnish loose steel bars that are free from kinks or bends that prevent them from being properly assembled or installed.
- Furnish approved chairs or chair bars designed to support the reinforcement in position without deflection or displacement during the placing and consolidation of the concrete. Use chair bases designed with sufficient bearing to prevent overturning or penetration into the subgrade, and that will not impede placement of the concrete. Chairs may be welded to the transverse bars prior to epoxy coating.
- If the support system does not hold the reinforcement within the specified tolerances, increase the number of chairs or take other steps to maintain proper positioning of the steel.
- 521.03.02 Placing Concrete. Place the concrete in one lift, vibrated internally over its full width and depth by immersion vibrators mounted at intervals of not more than 30 in. center to center across the full width of the slab. The vibrators shall have variably controlled frequencies. Operate the vibrators at the frequency and amplitude necessary to be perceptible on the surface of the concrete more than 1 ft in any direction. Mount the vibrators as a group advancing longitudinally with the paving machinery, hinge mounted to facilitate riding over obstructions, and set to clear the reinforcement by approximately 1/2 in.
- Stop all screeding and vibrating operations immediately whenever forward motion of the paving machinery is stopped.
- 521.03.03 Joints. Do not place transverse expansion or contraction joints in continuously reinforced Portland cement concrete pavement. Construct a transverse bulkhead joint whenever concreting operations are stopped for more than 30 minutes and at the end of any working period. Form the joints using an approved header board in conformance with the cross section of the pavement, placed at right angles to the center line, and perpendicular to the surface. Furnish and install additional bars as specified. Finish the pavement flush with the header board without edging. Complete the joints accurately and keep the bulkhead clean. Extend the roadway reinforcement continuously through the joint. Support the reinforcement extending through the joint securely on chairs or wooden sills to prevent deflection.
- Resume paving operations when the Engineer determines that the concrete has sufficiently set. Before resuming concrete placement, remove the bulkhead and debris and clean the joint.
- Seal all joints as specified in Section 523.
- 521.03.04 Terminal Joints. Construct terminal joints as specified.
- 521.03.05 Thickness Check. Refer to 520.03.10.
- 521.03.06 Pavement Profile. Refer to the pavement surface profile requirements in the Contract Documents.
521.04 MEASUREMENT AND PAYMENT
- Continuously Reinforced Portland Cement Concrete Pavement will be measured and paid for at the Contract unit price per square yard. The square yard measurement will conform to 520.04. The payment will be full compensation for all concrete, forms, reinforcement steel, chairs, epoxy coating, finishing, curing, joints, joint construction, saw cutting and joint sealing, and for all material, labor, equipment, tools, and incidentals necessary to complete the work.
- 521.04.01 Pavement Thickness Price Adjustment. Refer to 520.04.01.
- 521.04.02 Terminal Joints. Terminal Joints will be measured and paid for at the Contract unit price per linear foot. The payment will be full compensation for all steel beams, stiffener plates, end plates, drilled holes, welding, cutting, styrofoam, joint filler, concrete, reinforcement, bond breaker, and for all material, labor, equipment, tools, and incidentals necessary to complete the work.