471ASPHALT SEAL COAT USING PRECOATED AGGREGATE

471.1DESCRIPTION—This work is application of asphalt material immediately followed by an application

of asphalt precoated aggregate.

471.2MATERIAL—

Application Temperature °F Class of Material Type of Material Minimum Maximum

MC-30 Cut-back Asphalt 70 120 MC-70 Cut-back Asphalt 100 150 SS-1h Emulsified Asphalt 70 150 CSS-1h Cationic Emulsified Asphalt 70 150 PG 64S-22 Asphalt Cement 275 350 PG 58S-28 Asphalt Cement 250 325

Application Temperature °F Class of Material Type of Material Minimum Maximum

RS-2 Emulsified Asphalt 140 175 CRS-2 Cationic Emulsified Asphalt 140 175 PG 46S-40 Asphalt Cement 240 300

Only use PG 46S-40 on shoulders.

handled, and uniformly spread by a self-propelled spreader. Prepare pre-coated aggregate as follows:

aggregate to the Representative’s satisfaction. Provide a pre- coating with 0.6% to 1.2% residual asphalt binder (by weight of the mix). Dry the aggregate in a batch or continuous type asphalt plant conforming to the requirements of Bulletin 27. Precoat the aggregate in the pug mill. Mix the materials at a mixing temperature not exceeding 350F. Stock mixed material on a suitable base area and no higher than 4 feet.

Provide a pre- coating with 0.4% to 1.0% residual asphalt binder. If using damp aggregate with cut -back asphalts, sufficiently cure the pre- coated aggregate before use to prevent pickup. Do not exceed an aggregate temperature of 150F if using cutback asphalts. Select an application rate sufficient to provide a thin, brownish, and translucent film on the aggregate. Cover at least 90% of the total visible surface area of the aggregate. Before producing the pre- coated aggregate, prepare a sample of the pre-coated aggregate for the Representative’s inspection. The Representative will use the sample to establish the visual inspection standard associated with at least 90% of the visible surface area covered. During production, the Representative will determine if less than 90% of the visible surface area is covered. If the Representative determines less than 90% of the visible surface area is covered, the Contractor may determine the percent of uncoated material passing the 75 µm (No. 200) sieve after dry sieving for 10 minutes. The Representative will accept the pre-coated aggregate if the percent passing does

not exceed 0.5%. Stock mixed material on a suitable base area and, if using heated aggregates, no higher than 4 feet.

471.3CONSTRUCTION—Section 470.3 and as follows:

chips before and after opening the road to traffic. For emulsified asphalt, allow sufficient time for the seal coat to completely cure before opening the road to all traffic.

471.4MEASUREMENT AND PAYMENT—

The unit price includes the asphalt precoating material.