evaluating the effect of nano-al2o3 on the fatigue resistance of rubberized asphalt mixtures

Due to the traffic structure in iran and the excessive occurrence of loads to the surface of the pavement and then to the lower layers, the need to implement a resistant layer against to traffic loads in different weather conditions is quite obvious. in recent years, the upward trend in repair and maintenance costs for pavements has been increasing due to the increase in the amount and frequency of traffic loads on pavements, has led to an increase in the tendency to use modified asphalt mixtures, especially in areas with high traffics. many studies have been done to identify the appropriate additive for use to improve the behavior of bitumen and mixtures. the efficiency and effect of nano al2o3 as additive in bitumen and rubberized asphalt mixtures in order to improve their performance against external loads and environmental factors was evaluated in this study. in order to achieve the objectives of this study, bitumen with different percentages of nano al2o3 (0, 0.5, 1.0 and 1.5%) was combined and subjected to physical and rheological tests. also, for evaluating the functional properties of nano modified samples, various experiments were carried out including 4point bending fatigue test and wheel track. the results of this study show that improving the bitumen behavior in moderate and high temperatures can be led to decrease of fatigue and rutting failure in asphalt mixtures. evaluation on the results showed that using of 20% rubber powder and 1.5% al2o3 has the best effects on the rheological behavior of bitumen. also using of this bitumen can improve the asphalt mixture fatigue behavior.