Performance evaluation of fatigue resistance of asphalt mixtures modified by SBR/PP polymer blends and SBS

Using durable asphalt mixtures to increase the quality of pavement, improving the safety and comfort of drivers and reduce pavement damage and maintenance cost is inevitable. Major damage to asphalt pavement is fatigue, which happens due to everyday increase in traffic and the passing load. One way to improve the quality, strength and fatigue resistance of asphalt mixtures is to use high quality or modified, asphalt binder. This study aimed to use a polymer blend (a combination of two polymers) made of efficient and inexpensive polymers to modify the properties of asphalt binder and asphalt mixtures against fatigue. For this purpose, SBR and PP polymers with ratios of 70/30, 50/50 and 30/70, at 3, 4 and 5 wt% of asphalt binder were used, and the fatigue performance of asphalt mixtures containing these polymer blends was compared with that of asphalt mixtures containing 4% and 5% SBS polymer. Nanoclay CLOSITE 15A was used at 1.5 wt% of asphalt binder to increase the stability of polymers in asphalt binder. The results of bending beam fatigue, indirect tensile fatigue, indirect tensile strength, and resilient modulus tests performed on asphalt specimens showed that the use of polymer blends improves the fatigue performance of asphalt mixtures so that in samples containing 5% of polymer blends containing 50% and 70% SBR, fatigue life is increased by more than 50% compared to that of 5% SBS samples. Accordingly, it can be said that polymer blends can be used as an efficient and economical additive in asphalt mixtures.