Thickness Control. The completed thickness of the base course shall be within 12.5 mm (1/2 inch) of the thickness indicated. The thickness of the base course shall be measured at intervals providing at least one measurement for at least each 418 square meters (500 sq. yd) of base course. The depth measurement shall be made by test holes at least 75 mm (3 inches) in diameter. Where the measured thickness of the base course is more than 12.5 mm (1/2 inch) deficient, such areas shall be corrected by excavating to the required depth and replacing with new material. Where the measured thickness of the base course is 12.5 mm (1/2 inch) more than indicated, it will be considered as conforming with the requirements plus 12.5 mm (1/2 inch), provided the surface of the base course is within 12.5 mm (1/2 inch) below established grade and not above the established grade. The average job thickness shall be the average of the job measurements as specified above but within 6.25 mm (1/4 inch) of the thickness indicated.
Thickness Control. Ensure the spread rate is within 10% of the target spread rate, as indicated in the Contract. When calculating the spread rate, use, at a minimum, an average of five truckloads of mix. When the average spread rate is beyond plus or minus 10% of the target spread rate, monitor the thickness of the pavement layer closely and adjust the construction operations. If the Contractor fails to maintain an average spread rate within plus or minus 10% of the target spread rate for two consecutive days, the Engineer may elect to stop the construction operation at any time until the issue is resolved.
