Sustainable Nano-TiO2 modified asphalt with fine aggregate replacement using rubber powder

• Rubber powder was used to replace fine aggregates in asphalt for sustainability. • Nano-TiO was added to bitumen to improve asphalt’s rutting and fatigue resistance. • Using rubber powder reduced rutting, fatigue, and moisture resistance in asphalt. • Nano-TiO at 0.9 % compensated for performance loss due to rubber powder use. • An optimal mix (3 % rubber powder + 0.9 % nano-TiO) matched control mix performance. The widespread use of asphalt mixtures has increased the need for aggregates. Researchers are exploring alternative materials, such as rubber powder, which is commonly used to modify bitumen. In this research, the fine aggregates were replaced with different contents of rubber powder (1, 3, and 5 % by fine aggregate weight). Also, different contents of Nano-TiO₂ (0.3, 0.6, 0.9, and 1.2 % by bitumen weight) was used to improve the behavior of bitumen. Rutting, Fatigue and moisture susceptibility were investigated in these samples. The test results showed that although the use of rubber powder instead of aggregates has reduced the rutting resistance of the asphalt mixture by about 50 %, fatigue resistance by about 40 %, and moisture susceptibility by about 8 %, the use of Nano-TiO₂ can compensate. The most optimal condition from the technical and economic standpoint is to manufacture an asphalt mixture containing 3 % rubber powder and 0.9 % Nano-TiO 2 , in which the values of rutting, fatigue, and moisture susceptibility are approximately equal to that of the control specimen. This condition leads to a 3 % reduction in the use of natural aggregates compared to the control mixture.