Durability of Hot Asphalt Mixtures Containing Reclaimed Asphalt Pavements

The durability potential of bituminous mixtures may be defined as the resistance of the mixture to the continuous and combined damaging effects of water. High durability potential usually implies that the mechanical behavior of the mixture will endure for a long service life. Now, flexible pavement, made of hot-mix asphalt (HMA) with the addition of the reclaimed asphalt pavement granules in the central asphalt mixing plant, is increasingly used. The amount of the added reclaimed asphalt pavement (RAP) depends on mineral materials and their homogeneity. This paper presents the physical properties of RAP and their influence on the durability performance of a binder asphalt pavement mix. A series of binder mixes containing varying percentages of RAP were designed and subjected to different moisture conditioning periods (1, 3 and 7 days) to investigate the moisture damage effect on RAP mixtures. A mix made from only virgin material was selected as the control mix. The effect of RAP on the durability of binder course mix was evaluated through a series of laboratory tests including Marshall test, indirect tensile strength test and the water sensitivity tests where many moisture damage indicators were obtained such as retained Marshall stability, Marshall quotient, durability index, tensile strength ratio, resilient modulus ratio and energy loss ratio. The results indicated that the additional of RAP especially at 50% content was beneficial in improving the durability performance and reducing the moisture susceptibility of the hot mix asphalt mixtures.