Investigation of aggregate moisture content variation and its impact on pavement performance of WMA

Abstract For warm mix asphalt (WMA), aggregates cannot be completely dried due to the low heating temperature, which further adversely affects the pavement performance. This study aimed to (1) analyze the effect of particle size, heating temperature and heating time on the variation in the moisture content in aggregates, (2) compare the interaction ability between warm mix asphalt binders and aggregates with different moisture contents from a rheological perspective and (3) to study the effect of aggregate moisture contents on the pavement performance of WMA. Results show that the quadratic function can be used to express the decline in moisture content over time. The decline rate of moisture content increases with the decrease in particle size. The moisture content of fine aggregate dominates that of the whole aggregate system. The decline rate of moisture content exhibits strong temperature sensitivity in the heating temperature ranging from 110 °C to 150 °C. The sensitivities of different evaluation parameters of the asphalt-aggregate interaction were compared by sensitivity analysis. With the decrease in the moisture content of aggregates, the pavement performance of WMA can be improved. These findings provide understanding on the variation in aggregate moisture content during the heating process, and prove that reducing aggregate moisture content can improve the pavement performance of WMA.