The Experimental Investigation of Fatigue Life of Hot Mix Asphalt with Different Air Void Contents, Aggregate Type and Bitumen Grade at Low Temperature

Fatigue behavior of Asphalt pavement is dependent on different parameters, including the bitumen, Aggregate, and mixture design. This study aims to investigate the effects of different air void contents of asphalt mixes prepared using two common bitumen types in Iran, ۶۰/۷۰ and ۸۵/۱۰۰, and limestone as well as silica aggregates on the fatigue life of the asphalt mixes at ۵℃. First, the optimal amount of bitumen was calculated for each aggregate using the Marshall test. Then, to determine the fatigue behavior of the asphalt samples, indirect tensile tests were performed with controlled stresses at the levels of ۱۰۰, ۲۰۰, and ۳۰۰ kPa. The results indicated that the ۶۰/۷۰ bitumen sample had a longer fatigue life than the ۸۵/۱۰۰ bitumen sample. The effect of the changing the bitumen type from ۶۰/۷۰ to ۸۵/۱۰۰ on fatigue life is more noticeable than the effect of the changing the air void content. Furthermore, it was revealed that lime aggregates have a higher fatigue life in comparison to silica aggregates, and the influence of increasing the air void content on fatigue life reduction is larger than that of changing the aggregate type. Eventually, some models were proposed to describe the fatigue life of asphalt mixes with different materials and different air void contents based on experimental studies and numerical analyses.

Keywords:

Asphalt Mixture , Fatigue life , Low Temperature , Air void contents , ITF