Estimation of service-life reduction of asphalt pavement due to short-term ageing measured by GPC from asphalt mixture

Abstract

If the aggregate is heated higher than the specified level, the asphalt binder in the mixture will be aged at a much higher level during the short-term ageing (STA) period. The asphalt binder in that mixture will be oxidised (aged) more than expected during STA time due to the highly elevated temperature. If the binder in the mixture is severely oxidised, the asphalt pavement will have to lose its service life, or the expected service life will be reduced. Therefore, the objective of this study was to evaluate the ageing level of asphalt in the mixture at different STA temperatures and to estimate the service-life reduction (SLR) of asphalt mixture due to the STA. In this study, various temperatures were used for STA to evaluate ageing levels of the binder in the mixture before and after STA. A gel-permeation chromatography technique was used on the mixture particles without binder recovery to estimate the significance of ageing for each case of STA. Statistical analyses were carried out to examine the difference in ageing levels among STA temperatures. Statistical test results found that the ageing level of the binder after STA was significantly higher than that of binders before STA at α = 0.05 level. It was also found that the ageing level of binders in the warm-mix asphalt mixture was significantly lower than that of binders in hot-mix asphalt (HMA) after STA at the α = 0.05 level. It was also observed that if an HMA mixture was short-term aged at the higher temperature, a significant SLR could be induced due to the higher temperature during STA time.