541THIN BONDED CONCRETE OVERLAY OF ASPHALT-SURFACED PAVEMENT

PAVEMENT

541.1DESCRIPTION—This work is the construction of a thin Portland cement concrete overlay with a

thickness of 2.5 to 4 inches, and is bonded to an existing asphalt-surfaced pavement.

541.2MATERIAL—At least two weeks before commencing Portland cement concrete pavement placement,

submit concrete paving JMF(s) that have been approved by the District Materials Engineer/Manager to the Representative.

• Class AA Paving Cement Concrete. If the maturity method is used, correlate the degree- hours of cure to compressive strengths according to PTM No. 640 except, at time intervals of 8 hours, 1, 7, 28 and 56 days.

• Use concrete reinforced with synthetic or steel macrofibers according to Section 708.1(a).

If the overlay depth is less than 3 inches, use No. 67 coarse aggregate instead of No. 57 coarse aggregate. Add macrofiber at a rate to achieve the design residual strength value (f 150) according to Table B. Run ASTM C1609-12 at 14 days and calculate the residual strength versus fiber volume fraction for the selected fiber type.

TABLE B Remaining inches of Asphalt Concrete 3-4.5 4.5-6 Residual Strength in psi 200-275 175-250

Additional criteria for mix design acceptance of Thin Bonded Concrete Overlay of Asphalt -Surfaced Pavement concrete are as follows: The producer is required to complete the following tests before mix design submittal and approval.

• Permeability. Design the concrete mixture to meet a target chlorideion penetration of Low, Very Low, or Negligible after a 56 day or less curing period according to AASHTO T 277 or AASHTO T 358.

• The DME/DMM has the option of accepting mix designs with a chlorideion penetration of Moderate. The chlorideion penetration must meet one of the following:

• AASHTO T 277, Table 1, not to exceed 2,800 coulombs, or

• AASHTO T 358, Table 1, not to exceed 15.6kΩ-cm for 4-inch by 8-inch cylinders and 12.3 kΩcm for 6 inch by 12-inch cylinders.

541.3CONSTRUCTION—Section 540.3, modified as follows:

• The Department will divide the concrete overlay pavement into lots representing not more than 3,000 square yards of pavement in each traffic lane. Include ramps in a separate lot(s). The Inspector will select one coring location at random within each lot according to PTM No. 1. Drill cores according to PTM No. 606 and in the presence of the Inspector. For projects at intersections or less than 3,000 square yards, drill two cores or by non- destructive thickness measurements according to PTM No. 605. Other methods of non-destructive thickness testing may be requested in writing for approval by the District Executive. Thoroughly clean the vertical surface of the core hole of laitance and loose and foreign material. Fill the holes with the mixture used to construct the course and consolidate. As an alternative, use a premixed, non-shrink grout.

541.4MEASUREMENT AND PAYMENT—

Ownership of the milled material will be indicated by the selected item of work. The transition areas will be excluded.

This unit price includes all work associated with the construction of the concrete overlay, except the cement concrete material and the profile milling. The price excludes the concrete overlay transitions and the concrete pavement cores.

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 additional quantity, not to exceed 2% of the computed overlay quantity, may be paid as compensation for the cost of the cement concrete material needed to replace unsound pavement material removed as part of the profile milling operation. Excludes cement concrete material used in the transition areas. Submit written request for additional compensation with justification. The justification should indicate the cubic yardage of concrete delivered to the job site from delivery tickets, and show a deduction for the volume of the overlay and the quantity of concrete wasted.

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 if the depth is deficient by more than 1/4 inch.

cores, lot payment for both the bonded concrete overlay and the cement concrete material will be adjusted as specified in Table A.

TABLE A Adjustment for Depth Deficient in Depth Determined by Cores(inches) Payment Percent of Contract Unit Price, by Lot, Based on Nominal Overlay Depth (%) ≤ 4.00 inches -0.25 to 0.00 100 > -0.25 Defective Work

in place, final payment for this pavement will be at 5% of the contract unit prices of the concrete overlay and cement concrete.