Investigation of the Effect of Warm Mix Asphalt Additive on Fatigue Behavior of Bitumen and Asphalt Mixture Modified with Gilsonite and Crumb Rubber

The aim of this study was to investigate the effect of semi-hot asphalt additive on the fatigue performance of bitumen and asphalt mixtures with aggregate ossification containing rubber powder and gilsonite. In the present study, gilsonite, rubber powder and 2 semi-hot additives (3% Sasobit and also 0.3% Zycotherm) were used to modify pure bitumen (AC-85/100). Several bitumen rheological tests and mixed functional tests were performed. ANOVA was developed for data set analysis. The results of rheological behavior test showed that the addition of composite additives leads to an increase in the average temperature behavior of bitumen. The performance of asphalt bitumen at low temperatures deteriorated with the addition of gilsonite, while the use of rubber powder improved the performance of low temperatures. Storage stability test showed that using gilsonite up to 10% improves the storage stability of bitumen, although with increasing the percentage of gilsonite, the fuzzy separation of bitumen worsens. Bitumen fatigue life is increased by adding gilsonite and semi-hot additives. In addition, rubber powder can increase the fatigue behavior of Gilsonite-modified bitumen. The test results showed that the use of gilsonite, semi-hot additives and rubber powder increases the fatigue properties, fracture energy, tensile strength of the samples. Based on the results of the bulk modulus test, CR reduces the bulk modulus of the mixtures.