§ 11-131. Asphalt hot mix binder and asphalt hot mix surface courses.

The asphalt hot mix binder and surface courses shall meet the AHTD Standard Specifications for hot mix binder and surface courses with the following exceptions:

(1)

The depth of the asphalt hot mix binder course shall be within 3/8 inch of the required depth shown in Table 2, Appendix A. The average of all depth measurements shall be not less than the required depth shown in Table 2, Appendix A, and any depth in excess of + 3/8 inch shall not be used in computing the average depth.

(2)

The depth of the asphalt hot mix surface course shall be within ¼ inch of the depth shown in Table 1, Appendix A, plus any additional depth required as a result of deficient depth(s) of binder and base material. The average of all depth measurements shall be not less than the required depth, and any depth in excess of the + ¼ inch shall not be used in computing the average depth.

(3)

The crushed stone base course of cement treated crushed stone base course shall be primed. The prime coat shall meet the AHTD Standard Specification requirements for prime coat. The prime shall cure for at least seventy-two (72) hours, or as approved by the County Road Superintendent before placing any asphalt layer. EPR-1 can be substituted in lieu of MC-30. Curing time must be a minimum of two (2) hours.

(4)

Unless otherwise directed by the County Road Superintendent, a tack coat shall be used between succeeding asphalt layers. The tack shall meet the AHTD Standard Specification requirements for tack coat.

(5)

The binder course shall meet the AHTD gradation requirements for Type II binder course or Type II surface course.

(6)

The surface course shall meet the AHTD gradation requirements for Type II or Type III surface course.

(7)

The binder and surface course shall be designed with a minimum fifty-blow Marshall stability of one thousand (1,000) pounds; a flow of 8 to 16; and two (2) to five (5) percent air voids. A job mix formula shall be established and approved by the engineer for both the binder course and the surface course.

(8)

The supplier shall submit a materials certification giving the stability, gradation, asphalt type and content, flow, voids, and maximum theoretical density of both the binder and surface course mixes used.

(9)

Both binder course and surface course shall be compacted to a minimum of ninety-two (92) percent of maximum density as determined by the fifty-blow Marshall design procedures.

(10)

If the nuclear gauge is used to determine density, it must be correlated with cores taken from the roadway.

(11)

The minimum thickness of binder or surface course shall be two (2) inches. The maximum thickness that can be placed is four (4) inches provided the contractor can demonstrate that he can obtain the required density.

(12)

In no case shall the speed of any roller exceed three (3) miles per hour. If a vibratory roller is used for compaction, special care shall be taken not to decompact the mixture by over-rolling. The number of roller passes is very critical to proper compaction.

(13)

The surface course surface, when checked with a ten-foot straight edge parallel to the centerline, shall not exceed + or - one-fourth-inch.

(Ord. No. 91-9, Art. 1, § 4.12, 4-11-91; Ord. No. 99-32, Art. 1, 7-8-99)