Use of Nano SiO2 and Nano TiO2 to improve the mechanical behaviour of stone mastic asphalt mixtures

The service life of asphalt mixtures decreases due to heavy traffic and environmental conditions. Thus, pavement researchers are constantly trying to improve the HMA conditions, such as reducing the incidence rate of damages in the roads and delay the incidence time as much as possible. Stone mastic asphalt (SMA) is a type of hot mix asphalt which contains more coarse aggregate particles. The primary objective of this research is evaluation the effects of adding Nano SiO2 and TiO2 as modifier additives on mechanical behaviour of SMA mixtures. Nano SiO2 and TiO2 are studied as an additive in this research and, the effect of these Nano materials on mechanical behaviour of SMA is investigated by wheel track, indirect tensile fatigue, and indirect tensile stiffness modulus tests. Bitumen 60-70 is modified with different contents of Nano SiO2 and Nano TiO2 (0, 0.3, 0.6, 0.9 and 1.2%, respectively, by weight of the bitumen). The Results of this research show that adding the different percentages of Nano materials is capable to improve the mechanical behaviour of stone mastic asphalt, significantly.