545BONDED CONCRETE OVERLAY OF CONCRETE-SURFACED PAVEMENTS

PAVEMENTS

.1 DESCRIPTION —This work is the construction of a bonded concrete overlay, or inlay, of concrete pavements including surface preparation and joint sawing and sealing.

.2 MATERIAL—

• C oarse Aggregate, Type A, No. 57, No. 67, or No. 8 (Stone, Gravel, or Slag). Section 703.2, modified as follows:

eneral. Section 703.2, modified as follows:

tone. Provide durable stone, free from slate texture or cleavage planes. For use in cement concrete, wash thoroughly during production.

ravel. Provide durable gravel particles. For use in cement concrete, wash thoroughly during production.

last Furnace Slag Aggregate. Blast furnace slag aggregate is not allowed for use in cement concrete paving applications. • S ection 704.1(b) TABLE A modified as follows:

nimum Cement Factor for AA Slip Form Paving, Paving, and Accelerated Patching: 530 lbs/cu. yd. 2. Maximum Cement Factor for AA Slip Form Paving, and Paving (but not Accelerated Patching): 600 lbs/cu. yd. 3. Maximum Water-Cement Ratio: 0.42 lbs/lbs for all Class AA concrete.

elete Note 7 and replace with "The target Water-Cement Ratio is 0.40 lbs/lbs and will not fall below 0.38 lbs/lbs for all Class AA concrete."

esign Basis. Section 704.1(c), revised as follows: • A dd the following paragraph to the end of Section 704.1(c)2: For Class AA Paving, Portland cement may be replaced with supplementary cementitious material (flyash or slag cement) weighing as much or more than Portland cement replaced provided that at least 400 pounds per cubic yard of Portland cement is used and the total cementitious (cement plus supplementary cementitious material) content does not exceed the limits in Table A. The maximum slag cement content, if used, is not to exceed 30% of the total cementitious material, by weight. • R eplace the first sentence of Section 704.1(c)3 with the following: F or Class AA Slip -Form Paving, and AA Accelerated Patching concrete, design cement concrete to have an air content of 7.0%, within a tolerance of ± 1.5%, at the time and point of placement.

esting and Acceptance. Section 704.1(d), add the following:

4.c Verify Water-Cement Ratio. Verify water-cement ratio in the field using batch tickets (for cementitious content determination) and AASHTO T 318 "Standard Method for Test for Water Content of Freshly Mixed Concrete Using Microwave Oven Drying (for water content determination)."

• Replace the first sentence of the second paragraph in Section 704.1(g)2 with the following:

Use aggregates that are deemed reactive or potentially reactive with 14- day expansion betw een 0.10% and 0.30% only with an approved cement-supplementary cementitious material combination that is sufficient to mitigate the 14-day expansion to a value less than 0.1% and as specified in Section 704.1(g)3. Reject aggregate with 14-day expansion greater than 0.30%. This requirement applies to all paving concrete on this project. For other applications, use any of the cements or cement-supplementary cementitious material combinations specified in Section 704.1(g)3.

• Revise Section 704.1(g)3.b with the following:

3.b Blended Hydraulic Cemen t. Type IS or IP, ASTM C595, from a manufacturer listed in Bulletin 15. If any blended cement is used for any paving and patching concrete, the maximum allowable mortar expansion at 14 days and 8 weeks are 0.02% and 0.06%, respectively.

545.3CONSTRUCTION—Section 501.3, and as follows:

Place concrete when the concrete temperature is between 65F and 90F.

1.a Scarifying Equipment. Provide a self -propelled mechanical scarifier capable of uniformly removing the old surface across the entire cutting path, to the depth indicated, as specified in Section 591.3.

1.b Shot Blasting, Sand Blasting, or Water Blasting Equipment. Provide equipment capable of removing any loose concrete and rust from exposed reinforcement.

scarify the existing pavement surface to the depth indicated. Cut off and remove any reinforcement that is exposed and loose. After scarifying, remove any deteriorated concrete or asphalt materials that extend below the level of the scarification, as indicated, or directed. Remove all full-depth asphalt patches and replace with

concrete as specified in Section 516. Remove all loose material from the pavement surface before cleaning. Minimal minor repairs of surface defects can be replaced with overlay.

steel plates.

Provide measures, acceptable to the Department, to drain or remove standing water from the prepared surface as directed by the Department. Completely clean the prepared surface to remove all loose debris. Protect the cleaned and prepared surface from oil or grease drippings from compressors, concrete trucks, spreaders, pavers, etc. Remove all deleterious materials before overlaying. Conduct final cleaning of the surface in front of the paver no more than 30 minutes prior to the placement of the concrete overlay/inlay. If using a compressed air stream, ensure that it is free of oil, moisture, and other potential contaminants, and that has a minimum pressure of 100 pounds per square inch measured at the source. Install joint backing or other approved joint filling material to within ± 1/4 inch of the pavement surface in all existing transverse joints (including those associated with full-depth repairs) prior to placement of the overlay. Ensure that the joint backing or filling material cannot be dislodged by the paving operation. Immediately before placing the concrete overlay/inlay, ensure the surface is less than 120F. Fog-misting, protective covers or blankets will be allowed to achieve and maintain proper temperature and moisture conditions of the surface. Completely blow off standing water with compressed air from the pavement surface.

guide nails, tacks, or other Representative-approved devices to accurately mark the locations of the centers of all transverse joints before placing the concrete overlay so that they can be located after the overlay has been placed. Submit the proposed method of location marking for approval 20 days before the start of construction. Do not begin paving without approval.

overlay, test the prepared surface in the presence of the Inspector. Bond strength testing will be performed at 7 days, according to ASTM C1583. Provide the test equipment.

yards, the Inspector will select five test locations at random, according to PTM No. 1, and test according to ASTM C1583. If the average of the test results on the three tests is below 175 pounds per square inch and each individual test has a minimum strength of 160 pounds per square inch, the area represented will be considered defective. If defective, obtain additional tests at 100-foot intervals in both directions longitudinally from the defective locations to determine the limits of defective work. Each set of three defective tests will represent the condition in the same traffic lane for a distance of 50 feet in both directions longitudinally.

• Replace the first sentence of Section 501.3(l)1 with the following:

Apply curing materials after finishing and texturing operations, and within 30 minutes of the dissipation of bleed water and maintain them in place until the pavement has reached sufficient strength as specified in 545.3(l) for opening to traffic.

• Add the following paragraph to the end of Section 501.3(l)1:

Provide adequate insulating blankets to prevent rapid heat loss if the air temperature is forecasted to be 45F or less. Insulation may be removed when the air temperature exceeds 45F or when the average compressive strength of the concrete exceeds 3,600 pounds per square inch. Remove insulation in a

manner such that the rate of temperature change at the concrete surface does not exceed 40F within any 1-hour period. Concrete that experiences a higher rate of temperature change will be considered defective.

• Replace the second sentence of the second paragraph of Section 501.3(l)1.c with the following:

Apply curing compound homogenously to provide a uniform, solid white opaque coverage on all exposed concrete surfaces. Apply at a minimum rate of 1 gallon (± 0.1 gallon) per 125 square feet or as specified by the manufacturer’s recommendations, whichever is greater. If conditions warrant, the curing compound can be applied in two equal rates of application, with the first applied as stated previously and the second applied immediately after sawing operations have been completed. Joint faces must be protected from exposure to curing compound or cleaned thoroughly prior to sealant installation.

raveling or chipping, saw cut transverse joints directly over all existing transverse joints, including those produced by pre-overlay repairs. Saw cut depth must be equal to the full thickness of the overlay (including any additional thickness used for grade corrections) plus 1/2 inch, but must not result in damage to dowel load transfer devices in the original pavement. To prevent debonding, saw cut width should be at least the width of the underlying joint or crack in the existing pavement or greater. Measure joint widths immediately prior to placement of the overlay/inlay. When inlaying, saw cut transverse joints to the full depth of the inlay, including any extra depth concrete placed at the joint, directly over the existing transverse joint and a minimum of 1/2 inch wide. Construct a sealant reservoir as shown on the Standard Drawing for Cement Concrete Pavement Joints. The overlay may be sawed in a second operation, or make the initial saw cut equal to the required reservoir width. After sawing, immediately flush the joint with water to remove sawing slurry that might otherwise prevent proper sealant installation. Place backing material to the proper depth and seal the joints, as specified in Section 501.3(n). In the case of overlaying an existing Continuously Reinforced Concrete Pavement (CRCP), only match the terminal joints and joints created from full-depth repairs.

joints such that the overlay panel length does not exceed 15 feet. Saw cut depth must be equal to the full thickness of the overlay (including any additional thickness used for grade corrections) plus 1/2 inch.

area and between the adjacent lane and the overlay area, so that they can be accurately located after paving. After paving, saw cut a sealant reservoir, 1/4 inch wide, and the full depth of the overlay plus 1/2 inch, directly over the existing longitudinal joint. Seal joints as specified in Section 501.3(n). Provide a neat vertical edge face, free of honeycomb and segregation, longitudinally along both sides of the overlaid pavement.

Maximum edge slump allowed in the outside 6 inches next to an adjacent lane is 1/8 inch.

on when the concrete attains the minimum required compressive strength of 3,600 pounds per square inch as measured by compressive strength testing of cylinders in accordance with PTM No. 604, and the minimum acceptable bond strength as specified in Section 545.3(e).

replace pavement overlay that is defective in depth, as specified in Section 545.4(c) Table A; defective in air content, as specified in Section 704.1(c)3 (modified as specified in Section 545.2(a) ; defective in bond strength, as specified in Section 545.3(e); or showing surface defects resulting from the effects of rain, improper final finish, or honeycombing which, in the Representative's opinion, cannot be repaired.

Replace defective pavement overlay as specified in Section 501.3(t); except, provide a minimum pavement removal and replacement length between transverse joints of 6 feet.

545.4MEASUREMENT AND PAYMENT—

For producing the cement concrete needed for the overlay and delivering it to the jobsite. Pay quantity for the overlay will be computed based on the indicated depth and the placement area. An a dditional quantity, not to exceed 2% of the computed overlay quantity, will be paid as compensation for the cost of cement concrete material needed to replace unsound pavement material removed as part of the surface preparation operation. Excludes cement concrete material used in transition areas.

The unit price includes all work associated with construction of the concrete overlay except the cement concrete material and the surface preparation. Also excludes concrete overlay transitions and concrete pavement cores.

Where a deficiency exists, as determined by cores, lot payment for bonded concrete overlay will be adjusted as specified in Table A.

TABLE A Adjustment in Contract Price for Depth Deficient in Depth Determined by Cores (inches)

Payment Percent of Contract Unit Price, by Lot, Based on Nominal Overlay Depth -0.25 to 0.00 100% -0.30 to -0.26 95% -0.35 to -0.31 85% -0.40 to -0.36 75% -0.45 to -0.41 65% -0.50 to -0.46 50% > -0.50 Defective Work

place, unless otherwise directed in writing by the District Executive. When the District Executive directs that defective pavement be left in place, final payment for this pavement will be at 5% of the contract unit prices of the concrete overlay/inlay and the cement concrete.

This unit price includes all associated items of work within the limits of the transitions.

The price includes the measuring apparatus, which remains the Contractor's property upon completion of the project. The Department will not pay for additional cores drilled when the depth is deficient by more than 1/4 inch.