Rutting performance prediction of warm mix asphalt containing reclaimed asphalt pavements

摘要

Nowadays, saving energy and recycling materials are becoming priorities in the road construction industry. This paper presents an experimental study to characterise permanent deformation of a warm mix asphalt (WMA) mixture containing reclaimed asphalt pavement (RAP). The WMA mixtures containing 0%, 15%, 30%, 50% and 60% of RAP were plant prepared. To assess the impact of RAP on rutting properties of hot mix asphalt, mixtures were tested using Marshall and dynamic creep tests. It was found that replacing up to 60% of the virgin aggregate with RAP improved rutting properties of the asphalt mixtures because RAP increased asphalt binder's viscosity as a main factor of rutting, especially at high temperatures. However, replacement of too much RAP in asphalt mixtures can increase moisture sensitivity of flexible pavements. Therefore, an indirect tensile strength test was conducted to evaluate moisture damage of the mixtures. The results showed that the minimum permissible tensile strength ratio (TSR) of 70% was satisfied by replacing up to 50% of the virgin aggregate by RAP; but the mixtures with 60% RAP had a TSR of less than 70%. Accordingly, 50% replacement of RAP was found to be the optimal replacement level.