This report assesses various elements of the Washington State Department of Transportation (WSDOT) hot-mix quality assurance (QA) specification.
Current WSDOT QA specifications contain measures of in-place density, asphalt content, and aggregate gradation for contractor pay and special provisions allow for additional pay factor items based on volumetric properties. Data from production paving projects suggests that use of the original pay items are adequate in determining the quality of hot-mix asphalt (as opposed to pay items based on volumetric mix properties). Additionally, the option of increasing the minimum compaction level (currently 91 percent of theoretical maximum density) is recommended to increase quality.
In addition, a contractor quality control (QC) program is recommended for consideration by WSDOT.