Study on road performance of mechanical foamed warm-mix rubber-modified SMA asphalt mixture

Abstract

The mixing temperature of rubber-modified asphalt pavement is as high as 190°C, which consumes a lot of fuel and generates a lot of greenhouse gases and asphalt fumes. The mechanical foam warm mixing technology can significantly reduce the mixing temperature by 20 °C-40°C, effectively reducing the aging degree of rubber-modified asphalt. In this study, the optimal foaming conditions of rubber asphalt were determined by indoor asphalt foaming tests. The warm-mix rubber asphalt SMA mixtures were prepared by the mechanical foam method. Then the road performance research was conducted. The mixture's high-temperature shear resistance and fatigue performance were evaluated by the uniaxial penetration test and four-point bending fatigue test. The results show that under the condition of reducing the working temperature by 20°C, the penetration strength and water stability of foamed warm-mix rubber-modified mixture are slightly lower than that of the hot-mix rubber-modified asphalt mixture. The fatigue and low-temperature performance are better than the hot-mix rubber-modified asphalt mixture.