National Concrete Pavement Technology Center

Project description

At a minimum, WisDOT requires sodium sulfate soundness testing (AASHTO T104) and Los Angeles wear (AASHTO T96) aggregate quality testing be completed once every three years for quarried aggregate sources and once every five years for pit aggregate sources. Aggregate sources located in the Sinnippee geological group, generally in the southwest part of Wisconsin, require an additional freeze-thaw test (AASHTO T103) on a three-year or five-year testing cycle. An internal audit of WisDOT specifications concluded that the frequency of testing for quality is lacking relative to surrounding states. Reduced testing frequencies is due, in part, to the higher level of aggregate quality available to paving contractors in Wisconsin. Despite the inventory of high-quality construction aggregates, localized pavement performance issues have raised concerns about the effectiveness of the current quality testing program. Recent changes to the standard specifications have partially addressed concerns regarding the minimal quality testing frequencies, but there is a need to revisit quality thresholds and accuracy of current testing methods to represent aggregate durability.