The effect of temperature and stress level on the rutting performance of modified stone matrix asphalt

The aim of this study is to investigate the influence of temperature and stress level on the rutting performance of modified stone matrix asphalt (SMA). flow number (FN) test at three stress levels of 250, 350 and 450 kPa and at different temperatures of 40°C, 50°C and 60°C was performed on unmodified, ethylene-vinyl-acetate (EVA) and styrene-butadiene-styrene (SBS) modified SMA. Also, indirect resilient modulus was conducted to assess and compare the elastic response of modified asphalt mixtures. It was found that although EVA has greater rutting resistance than SBS at 40°C, its FN values drop below the SBS ones at 60°C due to the higher temperature sensitivity. Furthermore, the stress sensitivity of rutting performance decreases with temperature increase. Statistical analysis of the obtained results revealed that temperature always has a significant influence on FN values while the effect of stress level is significant just at 40°C. Also, although additives improve the FN significantly, there is the only slight difference between them.