Statistical Comparison Between SHRP Aggregate Physical and Chemical Properties and the Moisture Sensitivity of Aggregate-Binder Mixtures

ABSTRACT The physical and chemical properties of aggregates used in the construction of asphalt pavements play a significant role in establishing the moisture sensitivity of the pavement. However, distinguishing the level of contribution of each property has been difficult due to the limitation on the number of variables that can be practically studied in an experimental plan. This paper compares multiple predictor variables associated with the physical and chemical properties of eleven SHRP aggregates. The aggregates were mixed with eight SHRP binders, and the response variable was moisture sensitivity of compacted briquets determined by the freeze-thaw pedestal test. An accelerated failure time, linear regression analysis was used to compare the predictor variables and rank the aggregate properties that contribute to the moisture sensitivity of the briquets. The most important predictor was acid insolubility with calcium content, silicon content, loss on ignition, and the zeta potential all being highly correlated with acid insolubility. Porosity was the second most important predictor variable. In addition, iron, aluminum, and potassium content and surface area were found to impact moisture sensitivity, but these variables were not mutually exclusive.