(a) Curb and Gutter.
(1) Cross-section. The curb and gutter shall conform in cross-section with that specified by the County Road Commission, including the two continuous one-half inch diameter reinforcing rods as shown in drawings on file with the City Manager.
(2) Material. The concrete used in curb and gutter construction shall obtain a minimum strength of 3,500 pounds per square inch in twenty-eight days. The cement used shall be air-entraining with an air content of five percent, plus or minus one percent, by volume. The slump shall be at least one inch but not more than four inches. Concrete which does not meet the requirements of this paragraph shall be rejected.
(b) Subgrade. The subgrade shall be properly compacted in accordance with Michigan Department of Transportation Specifications and shall, if required, be properly drained with a tile underdrain. Following compaction and immediately prior to paving, the subgrade shall be fine graded with equipment utilizing a templated screed so that the exact crown and shape of the subgrade surface will be positively established. A final compaction by rolling shall immediately precede the paving.
(c) Base Course. The batch plant base course pavement material shall be in accordance with Section 4.09 of Michigan Department of Transportation Specifications, as amended, laid at a compacted uniform depth of 7.5 inches, within a tolerance of plus or minus 0.5 inch. The base course shall be laid in two separate courses of the thickness shown on the approved plans. Any modification of materials and/or procedures shall be approved by the City Manager in advance in writing.
(d) Bond Coat. A bituminous bond coat shall be applied between each layer of base course and between the base course and the surface course. The type of bond coat and the rate of application shall be as shown in the approved plans. No street plans specifying the surface covered in this section shall be considered complete or approved unless both the bond coat type and the rate of application are specified.
(e) Surface Course. The bituminous aggregate surface course shall be a batch plant mix in accordance with Section 4.11 of Michigan Department of Transportation Specifications, as amended. The surface course shall be laid at a uniform thickness of 1.5 inches within a tolerance of plus or minus 0.25 inch by equipment utilizing automatic screed controls. Any modification of materials and/or procedures shall be approved by the City Manager in advance in writing.