360Concrete Pavement

2.1 Hydraulic Cement Concrete. Pro vide hydraulic cement concrete in accordance with Item 421, “Hydraulic

Cement Concrete.” Use compressive strength testing unless otherwise shown on the plans. Provide Class P concrete designed to meet a minimum average compressive strength of 3,200 psi at 7 days or a minimum average compressive strength of 4,000 psi at 28 days. Test in accordance with Tex -418-A . Obtain written approval if the concrete mix design exceeds 520 lb. per cubic yard of cementitious material. Use coarse aggregates for continuously reinforced concrete pavements to produce concrete with a rated coefficient of thermal expansion not more than 5.5 × 10-6 in./in./°F as listed in accordance with the Concrete Rated Source Quality Catalog. Provide Class High Early Strength (HES) concrete designed to meet a minimum average compressive strength of 3,200 psi at 24 hr., for early opening of small pavement areas or leave- outs to traffic when shown on the plans or allowed. When opening of small pavement areas or leave- outs to traffic is less than 24 hr., design Class HES concrete to achieve a minimum average compressive strength of 1,800 psi at 8 hr.

2.2 Reinforcin g Steel . Provide Grade 60 or above deformed steel for bar reinforcement in accordance with

Item 440, “Reinforcement for Concrete.” Provide positioning and supporting devices (baskets and chairs) capable of securing and holding the reinforcing steel in proper position before and during paving. Provide corrosion protection when shown on the plans.

2.2.1 Dowels . Provide dowel bars for concrete pavements in accordance with DMS -7325, “Dowel Bars for

Concrete Pavements” and the MPL for “Dowel Bars for Concrete Pavements.” Provide dowel caps filled with a soft compressible material with enough range of movement to allow complete closure of the expansion joint.

2.2.2 Tie Bars. Provide straight deformed steel tie bars. Provide either multiple- piece tie bars or single- piece tie

bars as shown on the plans. Furnish multiple piece tie bar assemblies from the list of approved multiple- piece tie bars that have been prequalified in accordance with DMS -4515 , “Multiple Piece Tie Bars for Concrete Pavement,” when used. Multiple- piece tie bars used on individual projects must be sampled in accordance with Tex-711-I , and tested in accordance with Tex -712-I .

2.3 Curing Materials . Provide Type 2 membrane curing compound in accordance with DMS -4650 , “Hydraulic

Cement Concrete Curing Materials and Evaporation Retardants.” Provide asphaltic curing materials in accordance with Item 300, “Asphalts, Oils, and Emulsions,” for concrete pavement to be overlaid with asphalt concrete, unless otherwise shown on the plans or approved. Provide materials for other methods of curing in accordance with Item 422, “Concrete Superstructures.” When required, provide insulating blankets with a minimum thermal resistance (R) rating of 0.5 degree Fahrenheit square- foot per British T hermal U nit. Use insulating blankets that are free of tears and are in good condition. 450 2.4. Epoxy . Provide Type III, Class C epoxy in accordance with DMS -6100 , “Epoxies and Adhesives,” for installing all drilled -in reinforcing steel. Submit a work plan and request approval for the use of epoxy types other than Type III, Class C.

2.5 Evaporation Retardant. Provide evaporation retardant in accordance with DMS -4650 .

2.6 Joint Sealants and Fillers. Provide Class 5 or Class 8 joint sealant materials and fillers unless otherwise

shown on the plans or approved, and other sealant materials of the size, shape, and type shown on the plans in accordance with DMS -6310 , “Joint Sealants and Fillers.”

2.7 Repair Materials. Provide concrete repair materials in accordance with DMS -4655 , “Concrete Repair

Materials,” or DMS -6170 , “Polymeric Materials for Patching Spalls in Concrete Pavement.”

3.1 Placing, Consolidating, and Finishing Equipment . Provide self -propelled paving equipment that uniformly

distributes the concrete with minimal segregation and provides a smooth machine- finished consolidated concrete pavement conforming to plan line and grade. Provide an automatic grade control system on slip-forming equipment. Provide mechanically operated finishing floats capable of producing a uniformly smooth pavement surface. Provide equipment capable of providing a fine, light water fog mist. When using stringless paving equipment, use in accordance with Section 5.9.3., “Method C,” and establish control points at maximum intervals of 500 ft. Use these control points as reference to perform the work. Provide mechanically operated vibratory equipment capable of adequately consolidating the concrete. Provide immersion vibrators on the paving equipment at sufficiently close intervals to provide uniform vibration and consolidation of the concrete over the entire width and depth of the pavement and in conformance with the manufacturer’s recommendations. Provide immersion vibrator units that operate at a frequency in air of at least 8,000 cycles per minute. Provide enough hand- operated immersion vibrators for timely and proper consolidation of the concrete for concrete pavement (formed) placements, and along forms, at all joints, and in areas not covered by other vibratory equipment. Surface vibrators may be used to supplement equipment -mounted immersion vibrators. Provide tachometers to verify the proper operation of all vibrators. For small or irregular areas or when approved, the paving equipment described in this Section is not required.

3.2 Forming Equipment .

3.2.1 Pavement Forms . Provide side forms of sufficient cross -section, strength, and rigidity to support the paving

equipment and resist the impact and vibration of the operation without visible springing or settlement. Use forms that are free of detrimental kinks, bends, or warps that could affect ride quality or alignment. Provide bulkhead forms of sufficient cross -section, strength, and rigidity to support reinforcing steel and maintain alignment during concrete placement operations.

3.3 Curb Forms . Provide curb forms for separately placed curbs that are not slipformed that conform to the

requirements of Item 529, “Concrete Curb, Gutter, and Combined Curb and Gutter.”

3.4 Single -Piece Tie- Bar Inserting Equipment . Provide inserting equipment that accurately inserts and

positions reinforcing steel in the plastic concrete parallel to the profile grade and horizontal alignment as shown on the plans. 451 3.5. Texturing Equipment .

3.5.1 Carpet Drag . Provide a carpet drag mounted on a work bridge or a manual moveable support system.

Provide a single piece of carpet of sufficient transverse length to span the full width of the pavement being placed and adjustable so that a sufficient longitudinal length of carpet is in contact with the concrete being placed to produce the desired texture. Obtain approval to vary the length and width of the carpet to accommodate specific applications.

3.5.2 Tining Equipment . Provide a self -propelled metal tine device equipped with steel tines with cross -section

approximately 1/32 in. thick by 1/12 in. wide. Provide tines for longitudinal tining equipment spaced at approximately 3/4 in., center -to-center, or provide tines for transverse tining equipment spaced at approximately 1 in., center -to-center. Manual methods that produce an equivalent texture may be used when it is impractical to use self -propelled equipment, such as for small areas, narrow width sections, and emergencies due to equipment breakdown.

3.6 Curing Equipment . Provide a self -propelled machine for applying membrane curing compound using

mechanically pressuriz ed spraying equipment with atomizing nozzles. Provide equipment and controls that maintain the required uniform rate of application over the entire paving area. Hand- operated pressurized spraying equipment with atomizing nozzles may only be used on small or irregular areas, on narrow width sections, or in emergencies due to equipment breakdown.

3.7 Sawing Equipment . Provide power -driven concrete saws to saw the joints shown on the plans. Provide

standby power- driven concrete saws during concrete sawing operations.

3.8 Grinding Equipment . Provide self -propelled powered grinding equipment that is specifically designed to

smooth and texture concrete pavement using circular diamond blades when required. Provide equipment with automatic grade control capable of grinding at least a 3- ft. width longitudinally in each pass without damaging the concrete.

3.9 Testing Equipment . Provide testing equipment in accordance with Item 421, unless otherwise shown on the

plans or specified. Maintain and calibrate all Contractor -supplied testing equipment in conformance with pertinent test methods. Provide calibration records of strength- testing equipment to the Engineer within 1 week after each calibration.

3.10 Coring Equipment . Provide coring equipment capable of extracting cores in accordance with Tex-424-A

when required.

3.11 Miscellaneous Equipment. Furnish 10- ft. and 15- ft. steel or magnesium long- handled, standard

straightedges. Furnish enough work bridges, long enough to span the pavement, for finishing and inspection operations.

4.1 Paving and Quality Control (QC) Plan. Submit a paving and QC plan for approval before beginning

pavement construction operations. Include details of all operations in the concrete paving process, including methods to construct transverse joints, methods to consolidate concrete at joints, longitudinal construction joint layout, sequencing, curing, lighting, early opening, leave- outs, sawing, inspection, contractor QC testing, testing for opening to traffic, construction methods, other details, and description of all equipment. List 452 certified personnel performing contractor QC testing and testing for opening to traffic. Subm it revisions to the paving and QC plan for approval.

4.2 Placing Reinforcing Steel for Continuously Reinforced Concrete Pavements. Accurately place and

secure in position all reinforcing steel as shown on the plans. Provide chairs in sufficient number to adequately support the reinforcing steel at the proper height as show on the plans. Secure reinforcing steel at alternate intersections with tie wires. Reinforcing steel intersections may be secured with locking support chairs instead of tie wires. Anchor pins used to prevent the reinforcing steel from shifting may remain in the final pavement. Stagger the lap locations so that no more than 1/3 of the longitudinal steel is spliced in any given 12- ft. width and 2- ft. length of the pavement. Tie all splices with tie wires.

4.3 Joints . Install formed joints as shown on the plans. Install transverse bulkhead forms to support extending

reinforcing steel, shaped accurately to the cross -section of the pavement when placing of concrete is stopped.

4.3.1 Placing Reinforcement at Joints. Install rei nforcing steel at transverse construction joints as shown on the

plans. Use multiple- piece tie bars, drilled and epoxy -grouted tie bars, or mechanically inserted single -piece tie bars at longitudinal construction joints. Discontinue the use of mechanically inserted single- piece tie bars if this method results in steel misalignment or improper location, poor concrete consolidation, or other inadequacies. Protect the reinforcing steel immediately beyond the construction joint from damage, vibration, and impac t. For drilled and epoxy -grouted tie bars, drill holes into the existing concrete at least 10 in. deep unless otherwise directed. Use a drill bit with a diameter that is 1/8 in. greater than that of tie bars. Clean the holes using a wire brush and compress ed air to remove all the dust and moisture. Only cartridge or machine applicator epoxies are allowed. Follow the epoxy manufacturer’s instructions to apply the epoxy. Insert the tip of the epoxy cartridge or the tip of the machine applicator to the end of the tie bar hole, and inject Type III, Class C, epoxy to fill the hole with the amount of epoxy recommended by the manufacture for the size of bar and depth of hole. Insert tie bars.

4.3.2 Testing of Tie Bars . Verify that tie bars that are drilled and epoxied or mechanically inserted into concrete at

longitudinal construction joints develop a pullout resistance equal to at least 3/4 of the yield strength of the reinforcing steel. Test pullout resistance of mechanically inserted tie bars when the concrete pavement is at least 7 days old. Test pullout resistance of epoxy -grouted bars after the epoxy manufacturer’s recommended final cure time. Test 15 bars in accordance with ASTM E488, except that alternate approved equipment may be used. All 15 tested bars must meet the required pullout strength. Perform corrective measures to provide equivalent pullout resistance if any of the test results do not meet the required minimum pullout strength. Repair damage from testi ng.

4.3.3 Testing of Epoxy -Grouted Longitudinal Bars in Continuously Reinforced Concrete Pavements . When

longitudinal reinforcing steel is drilled and epoxy -grouted in existing pavement, test each bar in accordance with ASTM E488, except that alternate approved equipment may be used. All bars must develop a pullout resistance equal to at least 3/4 of the yield strength of the steel. Test pullout resistance after the epoxy manufacturer’s recommended final cure time. Perform corrective measures to provide equivalent pullout resistance if any of the test results do not meet the required minimum pullout strength. Repair damage from testing.

4.3.4 Transverse Construction Joints for Concrete Pavement Contraction Design (CPCD) . Install and rigidly

secure a complete joint assembly and bulkhead in the planned transverse contraction joint location when the placing of concrete is intentionally stopped. Install a transverse construction joint either at a planned transverse contraction joint location or mid- slab between planned transverse contraction joints when the placing of concrete is unintentionally stopped. Install tie bars of the size and spacing used in the longitudinal joints for mid -slab construction joints. Place dowels at mid- depth of the pavement slab, parallel to the surface. Place dowels for transverse contraction joints parallel to the pavement edge. Tolerances for location and alignment of dowels will be shown on the plans. For dowels used in a contraction joint, coat the entire length of the dowels with a thin 453 film o f grease, wax, silicone, or other approved de-bonding material. For dowels used in an expansion joint, coat half the length with a thin film of grease, wax, silicone, or other approved de- bonding material; provide dowel caps on the coated half of each dowel bar.

4.4 Curb Joints . Construct curb joints in accordance with Item 529.

4.5 Placing and Removing Forms . Use clean and oiled forms. Secure forms on a base or firm subgrade that is

accurately graded and that provides stable support without deflection and movement by formriding equipment. Pin every form at least at the middle and near each end. Tightly join and key form sections together to prevent relative displacement. Set side forms far enough in advance of concrete placement to permit inspection. Check conform ity of the grade, alignment, and stability of forms immediately before placing concrete, and make all necessary corrections. Use a straightedge or other approved method to test the top of forms to ensure that the ride quality requirements for the completed pavement will be met. Stop paving operations if forms settle or deflect more than 1/8 in. under finishing operations. Reset forms to line and grade, and refinish the concrete surface to correct grade. Avoid damage to the edge of the pavement when removing side forms and bulkhead forms. Repair damage resulting from form removal with an approved repair material within 24 hr. after form removal unless otherwise approved. Chip excessively honeycombed areas to sound concrete, and repair with an approved repair material within 24 hr. after form removal unless otherwise approved. Clean joint face within 24 hr. after a bulkhead for a transverse construction joint has been removed unless otherwise approved. Promptly apply membrane curing compound to the edge of the concrete pavement when forms are removed before 72 hr. after concrete placement. Forms that are not the same depth as the pavement but within 2 in. of that depth are permitted if the subbase is trenched or the full width and length of the form base are supported with a firm material to produce the required pavement thickness. Promptly repair the form trench after use. Use flexible or curved wood or metal forms for curves of 100- ft. radius or less.

4.6 Concrete Delivery. Clean delivery equipment as necessary to prevent accumulation of old concrete before loading fresh concrete. Use agitated delivery equipment for concrete designed to have a slump of more than 5 in. Segregated concrete is subject to rejection.

Begin the discharge of concrete delivered in agitated delivery equipment in accordance with Item 421. Place non-agitated concrete within 45 min. after batching. Reduce times as directed when hot weather or other conditions cause quick setting of the concrete.

4.7 Concrete Placement . Do not allow the pavement edge to deviate from the established paving line by more

than 1/2 in. at any point. Place the concrete as near as possible to its final location, and minimize segregation and rehandling. Distribute concrete using shovels where hand spreading is necessary. Do not use rakes or vibrators to distribute concrete.

4.7.1 Consolidation. Consolidate all concrete using approved mechanical vibrators operated on the front of the

paving equipment. Use immersion- type vibrators that simultaneously consolidate the full width of the placement when machine finishing. Keep vibrators from dislodging reinforcement. Use hand- operated vibrators to consolidate concrete for concrete pavement (formed) placements, and along forms, at all joints, and in areas not accessible to the machine- mounted vibrators. Do not operate machine-mounted vibrators while the paving equipment is stationary. Vibrator operations are subject to review.

4.7.2 Curbs . Curbs will be in accordance with Item 529.

4.7.3 Temperature Restrictions. Place concrete that is between 40°F and 95°F when measured in accordance

with Tex-422-A at the time of discharge, except that concrete may be used if it was already in transit when the temperature was found to exceed the allowable maximum. Take immediate corrective action or cease concrete production when the concrete temperature exceeds 95°F. 454 Do not place concrete when the ambient temperature in the shade is below 40°F and falling, unless approved. Concrete may be placed when the ambient temperature in the shade is above 35°F and rising or above 40°F. Protect the pavement with an approved insulating material capable of protecting the concrete for the specified curing period when temperatures warrant protection against freezing. Submit for approval proposed measures to protect the concrete from anticipated freezing weather for the first 72 hr. after placement. Repair or replace all concrete damaged by freezing.

4.8 Spreading a nd Finishing. Finish all concrete pavement using approved self -propelled equipment. Use

power -driven spreaders, power- driven vibrators, power- driven strike -off screed, or approved alternate equipment to strike- off the surface of the concrete to the required section and grade without surface voids. Use float equipment for final finishing. Use concrete with a consistency that allows completion of all finishing operations without addition of water to the surface. Use the minimal amount of water fog mist necessary to maintain a moist surface. Reduce fogging if float or straightedge operations result in excess slurry.

4.8.1 Finished Surface . Perform sufficient checks using a minimum 10- ft. long straightedge on the plastic

concrete to ensure the final surface is within the tolerances specified in Surface Test A in accordance with Item 585, “Ride Quality for Pavement Surfaces.” Check with the straightedge parallel to the centerline.

4.8.2 Maintenance of Surface Moisture. Prevent surface drying of the pavement before application of the curing

system by means that may include water fogging, the use of wind screens, or the use of evaporation retardants. Apply evaporation retardant at the manufacturer’s recommended rate. Reapply the evaporation retardant as needed to maintain the concrete surface in a moist condition until curing system is applied. Do not use evaporation retardant as a finishing aid. Failure to take acceptable precautions to prevent surface drying of the pavement will be cause for shutdown of pavement operations.

4.8.3 Surface Texturing . Complete final texturing before the concrete has attained its initial set. Drag the carpet

longitudinally along the pavement surface with the carpet contact surface area adjusted to provide a satisfactory coarsely textured surface. Prevent grout from plugging the carpet. Do not perform carpet dragging operations while there is excessive bleed water. A metal -tine texture finish is required unless otherwise shown on the plans. Provide longitudinal tining unless otherwise shown on the plans. Immediately following the carpet drag, apply a single coat of evaporation retardant, if needed, at the rate recommended by the manufacturer. Provide the metal -tine finish immediately after the concrete surface has set enough for consistent tining. Operate the metal -tine device to obtain grooves approximately 3/16 in. deep, with a minimum depth of 1/8 in., and approximately 1/12 in. wide. Do not overlap a previously tined area. Use manual methods to achieve similar results on ramps, small or irregular areas, and narrow width sections of pavements. Repair damage to the edge of the slab and joints immediately after texturing. Do not tine pavement that will be overlaid or that is scheduled for blanket diamond grinding or shot blasting. Target a carpet drag texture of 0.04 in., as measured by Tex -436-A , when carpet drag is the only surface texture required on the plans. Ensure adequate and consistent macro- texture is achieved by applying enough weight to the carpet and by keeping grout from plugging the carpet. Correct any location with a texture less than 0.03 in. by diamond grinding or shot blasting. The Engineer will determine the test l ocations at points located transversely to the direction of traffic in the outside wheel path.

4.8.4 Small, Irregular Area, or Narrow Width Placements. Use hand equipment and procedures that produce a consolidated and finished pavement section to the line and grade where machine placements and finishing of concrete pavement are not practical.

4.8.5 Emergency Procedures. Use hand- operated equipment for applying texture, evaporation retardant, and

cure in the event of equipment breakdown.

4.9 Curing. Keep the concrete pavement surface from drying in accordance with Section 360.4.8.2., “Maintenance of Surface Moisture,” until the curing material has been applied. Maintain and promptly repair damage to curing materials on exposed surfaces of concrete pavement continuously for at least 3 curing

days. A curing day is defined as a 24- hr. period when either the temperature taken in the shade away from 455 artificial heat is above 50°F for at least 19 hr. or the surface temperature of the concrete is maintained above 40°F for 24 hr. Curing begins when the concrete curing system has been applied. Stop concrete paving if curing compound is not being applied promptly and maintained adequately. Other methods of curing in accordance with Item 422 may be used when specified or approved.

4.9.1 Membrane Curing . Spray the concrete surface uniformly with two coats of membrane curing compound at

an individual application rate of no more than 180 sq. ft. per gallon. Apply the curing compound before allowing the concrete surface to dry. Manage finishing and texturing operations to ensure placement of curing compound on a moist concrete surface, relatively free of bleed water, to prevent any plastic shrinkage from cracking. Time the application of curing compound to prevent plastic shrinkage from cracking. Maintain curing compounds in a uniformly agitated condition, free of settlement before and during application. Do not thin or dilute the curing compound. Apply additional compound at the same rate of coverage to correct damage where the coating shows discontinuities or other defects or if rain falls on the newly coated surface before the film has dried enough to resist damage. Ensure that the curing compound coats the sides of the tining grooves.

4.9.2 Asphalt Curing. Apply a uniform coating of asphalt curing at a rate of 90 sq. ft. –180 sq. ft. per gallon when

an asphaltic concrete overlay is required. Apply curing immediately after texturing and once the free moisture (sheen) has disappeared. Obtain approval to add water to the emulsion to improve spray distribution. Maintain the asphalt application rate when using diluted emulsions. Maintain asphalt emulsions in a mixed condition during application.

4.9.3 Curing Class HES Concrete. Provide membrane curing in accordance with Section 360.4.9.1., “Membrane

Curing,” or wet mat curing in accordance with Section 422.4.8., “Final Curing,” for all Class HES concrete.

4.10 Sawing Joints . Saw joints to the depth shown on the plans as soon as sawing can be accomplished without

damage to the pavement, regardless of time of day or weather conditions. Some minor raveling of the saw - cut is acceptable. Use a chalk line, string line, sawing template, or other approved method to provide a true joint alignment. Provide enough saws to match the paving production rate to ensure sawing completion at the earliest possible time to avoid uncontrolled cracking. The Engineer will evaluate the cause of the uncontrolled cracking and direct any necessary repairs. Reduce paving production if necessary to ensure timely sawing of joints. Promptly restore membrane cure damaged within the first 72 hr. of curing. The Engineer will check the depth of saw cuts in accordance with Tex-423-A within 24 hrs. after saw -cutting or before joints are sealed, whichever is sooner. Frequency of checks will be as follows:  every 500 ft. or fraction thereof for all longitudinal contraction joints, and  10% of transverse contraction joints in CPCD for each daily placement. Resaw contraction joints that are deficient in depth by more than 1/4 in. from plan depth within 24 hr. of depth checks.

4.11 Cleaning and Sealing Joints . Clean and seal joints in accordance with Item 438, “Cleaning and Sealing

Joints.” Repair excessive spalling of the joint saw groove using an approved method before installing the sealant. Seal all joints before opening the pavement to all traffic. Joint sealants are not required on concrete pavement that is to be overlaid with asphaltic materials.

4.12 Protection of Pavement . Erect and maintain barricades and other standard and approved devices that will

exclude all vehicles and equipment from the newly placed pavement for the periods specified. Protect the pavement from damage due to crossings using approved methods before opening to traffic. Where a detour is not readily available or economically feasible, an occasional crossing of the roadway with overweight equipment may be permitted for relocating equipment only, but not for hauling material. When an occasional 456 crossing of overweight equipment is permitted, temporary matting or other approved methods may be required. Maintain an adequate supply of sheeting or other material to cover and protect fresh concrete surface from weather damage. Apply as needed to protect the pavement surface from weather.

4.13 Opening to Traffic . Testing for opening pavement to traffic is the responsibility of the Contractor unless

otherwise shown on the plans or as directed. Before opening pavement to traffic:  provide test results to the Engineer for review, if necessary,  clean pavement,  place stable material against pavement edges,  seal joints, and  perform all other traffic -safety related work.

4.13.1 Opening Pavement to All Traffic. Pavements can be open to all traffic:

 when the pavement is 7 days old,  when 3- day curing is complete and the concrete has attained a compressive strength of 3,200 psi,  after 24 hr. and the concrete has attained a compressive strength of 3,200 psi when Class HES concrete is used, or  after the concrete has been cured for at least 8 hr. and attained a minimum compressive strength of 1,800 psi when Class HES concrete is used.

4.13.2 Opening Pavement to Construction Equipment . Unless otherwise shown on the plans, concrete

pavement may be opened to concrete paving equipment and related delivery equipment after the concrete is at least 48 hr. old and has attained a compressive strength of 3,200 psi. Keep delivery equipment at least 2 ft. from the edge of the concrete pavement. Keep tracks of the paving equipment at least 1 ft. from the pavement edge. Protect textured surfaces from the paving equipment. Restore damaged membrane curing as soon as possible. Repair pavement damaged by paving or delivery equipment before opening to all traffic.

4.13.3 Maturity Method. Maturity method, in accordance with Tex -426-A

, may be used to estimate concrete strength for opening pavement to traffic. Install at least two maturity sensors for each day’s placement in areas where the maturity method will be used for opening. Maturity sensors, when used, will be installed near the day’s final placement for areas being evaluated. The Engineer will test specimens to verify the strength-maturity relationship in accordance with Tex -426-A . The strength- maturi ty relationship will be verified at least every 10 days of production after the first day. Establish a new strength- maturity relationship when the strength specimens deviate more than 10% from the maturity -estimated strengths. Suspend use of the maturity method for opening pavements to traffic when the strength- maturity relationship deviates by more than 10% until a new strength- maturity relationship is established. The Engineer will determine the frequency of verification when the maturity method is used intermittently or for only specific areas.

4.13.4 Emergency Opening to Traffic . Open the pavement to traffic under emergency conditions, when the

pavement is at least 72 hr. old, when directed in writing.

4.14 Sampling and Testing of Concrete . Unless otherwise specifi ed, a ll fresh and hardened concrete is subject

to testing as follows.

4.14.1 Fresh Concrete . Provide safe access and assistance to the Engineer during sampling. Fresh concrete will

be sampled in accordance with Tex -407-A . 457 4.14.2. Testing Concrete . The Engineer will test the fresh and hardened concrete in accordance with the following methods:  Slump. Tex-415-A , only for formed concrete pavement placements;  Air Content . Tex-414-A or Tex-416-A, only when air -entrained concrete is shown on the plans;  Temperature. Tex -422-A;  Making and Curing Strength Specimens . Tex-447-A ;  Compressive Strength . Tex-418-A; and  Maturity . Tex-426-A . Maturity specimens will be made only when maturity method is used or shown on the plans. Concrete with slump less than minimum required after all addition of water withheld will be rejected, unless otherwise allowed by the Engineer. Concrete with slump exceeding maximum allowed may be used at the Contractor’s option. If used, Engineer will make, test, and evaluate strength specimens in accordance with Section 360.4.15., “Acceptance of Concrete Pavement.” Acceptance of concrete not meeting air content or temperature requirements will be determined by Engineer. Fresh concrete exhibiting segregation and excessive bleeding will be rejected. 4.14.2.1. Strength Specimen Handling. After strength test specimens are molded, protect and cure in conformance with pertinent test methods. When necessary, deliver Contractor -molded specimens to curing facilities, remove specimens from their molds, and place specimens in curing tanks within 24– 48 hr. after molding, in conformance with pertinent test methods. The Engineer will deliver Department -molded specimens to curing facilities, remove specimens from their molds, and place specimens in curing tanks within 24–48 hr. after molding, in conformance with pertinent test methods.

4.15 Acceptance of Concrete Pavement . The Engineer will determine pay adjustments for deficient pavement

thickness within 14 days after concrete pavement has been cored. The Engineer will determine structural adequacy of low concrete strengths within 7 days after design strength specimens or cores, if taken, are tested.

4.15.1 Pavement Thickness. The Engineer will check the thickness in accordance with Tex -423-A

unless other methods are shown on the plans. The Engineer will perform one thickness test consisting of one reading at approximately the center of the paving equipment every 500 ft. or fraction thereof. Core where directed, in accordance with Tex-424-A , to verify deficiencies. Do not core until pavement is at least 7 days old or has achieved design strength. Fill core holes using an approved concrete mixture and method. 4.15.1.1. Assessing Payment Adjustments. Limits for applying a payment adjustment for deficient pavement thickness are 500 ft. units of pavement in each lane. Lane width will be as shown on typical sections and in conformance with pavement design standards. The limits for retaining deficient pavement without compensation or removing and replacing without additional compensation will be defined by coring or equivalent nondestructive means as determined by the Engineer. The remaining portion of the 500-ft. unit allowed for pay adjustment will be subject to the payment adjustment based on the average core thickness deficiency at each end of the 10- ft. interval investigation as determined by the Engineer. Shoul ders will be measured for thickness unless otherwise shown on the plans. Shoulders 6 ft. wide or wider will be considered as lanes. Shoulders less than 6 ft. wide will be considered part of the adjacent lane. Shoulders less than 6 ft. wide and placed separately from the adjacent lane will b e considered as a lane. Limits for applying payment adjustment for deficient pavement thickness for ramps, widenings, acceleration and deceleration lanes, and other miscellaneous areas are 500- ft. units. Areas less than 500- ft. units will be individually evaluated for payment adjustment based on the plan area. 458 4.15.1.2. Verification of Thickness Deficiencies. When any fresh depth test measured in accordance with Tex-423-A is deficient by more than 0.50 in. from the plan thickness, take one 4- in. diameter core at that location to verify the measurement. When determining the average thickness deficiency for assessing a pay adjustment other than retaining pavement without compensation or remove and replace as shown in Table 1 , take at least two additional cores from the unit, in accordance with Section 360.4.15.1.1., “Assessing Payment Adjustments,” equidistantly spaced from the first core in each direction if the first core is deficient by more than 0.50 in. from the plan thickness. Measure the length of cores in accordance with Tex -424-A . Determine the average thickness by averaging the lengths of the cores. Subtract the calculated average thickness from the plan thickness to determine the average thickness deficiency. In calculations of the average thickness, measurements exceeding the plan thickness by more than 0.2 in. will be considered as the plan thickness plus 0.2 in. When determining the limits for retaining the deficient pavement without compensation or remove and replace without additional compensation, take additional cores at 10- ft. intervals in each direction parallel to the centerline to determine the boundary of the deficient area if the first core length deficiency is more than

1.00 in. for pavements less than 11 in. thick or more than 1.50 in. for pavements 11 in. or thicker. Continue

taking cores at 10- ft. intervals until the core length deficiency is less than 1.00 in. for pavements less than 11 in. thick or less than 1.50 in. for pavements 11 in. or thicker.

4.15.2 Strength of Concrete Pavement . The Engineer will accept concrete pavement meeting a compressive

strength of 3,200 psi at 7 days or meeting a compressive strength of 4,000 psi at 28 days for Class P concrete. Concrete strength testing may be correlated to an age other than 7 days in accordance with Tex -427-A when approved. The Engineer will accept concrete pavement using Class HES concrete based on the required strength and time. Investigate the strength test procedures, the quality of materials, the concrete production operations, and other possible problem areas to determine the cause when a concrete strength test value is more than 10% below the required strength or when three consecutive strength values fall below the required strength. Take necessary action to correct the problem, including redesign of the concrete mix if needed. The Engineer may suspend concrete paving if the Contractor is unable to identify, document, and correct the cause of low-strength test values in a timely manner. The Engineer will evaluate the structural adequacy of the pavements if any strength is more than 15% below the required strength. Remove and replace pavements found to be structurally inadequate at no additional cost when directed.

4.15.3 Ride Quality. Measure and correct ride quality in accordance with Item 585, unless otherwise shown on the

plans.

5.1 Concrete Pavement . Concrete pavement will be measured by the square yard of surface area in place. The

surface area includes the portion of the pavement slab extending beneath the curb.

6.1 Concrete Pavement . The work performed and materials furnished in accordance with this Item and

measured as provided under “Measurement” will be paid for at the unit price bid for “Concrete Pavement” of 459 the type and depth specified as adjusted in accordance with Section 360.6.2., “Deficient Thickness Adjustment.”

6.2 Deficient Thickness Adjustment . Where the average thickness of pavement is deficient in thickness,

payment will b e made using the adjustment factor in accordance with Table 1 applied to the bid price for the deficient area for each unit in accordance with Section 360.4.15.1.1. , “Assessing Payment Adjustments.” When pavement thickness investigation (coring) is conduct ed for three consecutive placements, remove and replace without additional compensation all pavement placed during these days if the average thickness deficiency from all cores taken from these consecutive placements is greater than 0.25 in. Table 1 Defic ient Thickness Price Adjustment Factor Deficiency in Thickness Determined by Cores (in.) Proportional Part of Contract Price Allowed (Adjustment Factor) for Thickness <11 inches Not deficient 1.00 Over 0.00 through 0.50 1.00 Over 0.50 through 0.75 0.80 Over 0.75 through 1.00 0.60 Over 1.00 through 1.25 Retain pavement without compensation or Remove and Replace Over 1.25 Remove and Replace Deficiency in Thickness Determined by Cores (in.) Proportional Part of Contract Price Allowed (Adjustment Factor) for Thickness ≥11 inches Not deficient 1.00 Over 0.00 through 0.50 1.00 Over 0.50 through 0.75 0.90 Over 0.75 through 1.00 0.80 Over 1.00 through 1.50 0.60 Over 1.50 through 2.00 Retain pavement without compensation or Remove and replace Over 2.00 Remove and replace

6.3 Curb . All curbs will be paid for under Item 529.