State of the art review on inorganic powders modified asphalt materials: reducing the temperature of asphalt pavement

To reduce the temperature diseases of asphalt pavement, improve the service quality of road and extend service life, the research of inorganic powders that reduce the temperature of asphalt pavements was systematically sorted out. The common types, physicochemical properties and application methods of inorganic powders were defined. The road performances of modified asphalt and its mixture were evaluated. The modification mechanism of inorganic powders in asphalt was analyzed. On this basis, the cooling effect and cooling mechanism of inorganic powders was revealed. The results indicate that inorganic powders are classified into hollow, porous, and energy conversion types. The high-temperature performance of inorganic powders modified asphalt and its mixture is significantly improved, while there is no significant change in low-temperature performance and water stability. The average increase in rutting resistance factor (G^*/sin(δ)) and dynamic stability is 40%-72% and 30%-50%, respectively. The modification mechanism of inorganic powders in asphalt is physical blending. The thermal conductivity of hollow and porous inorganic powders modified asphalt mixture decreases by 30.05% and 43.14%, respectively. The temperature of hollow, porous and energy conversion inorganic powders modified asphalt mixture at 5 cm decreases by 2.3 ℃-3.5 ℃, 0.8 ℃-3.7 ℃ and 4.1 ℃-4.7℃, respectively. Hollow and porous inorganic powders block heat conduction, while energy conversion inorganic powders achieve cooling through their functional properties.