Effect of Incineration Temperature on the Properties of Rice Husk Ash (RHA) and Its Modified Asphalt

To investigate the influence of rice husk ash (RHA) prepared at different incineration temperatures on its properties and the performance of its modified asphalt, the amorphous SiO2 content in RHA was determined using X-ray fluorescence spectrometry (XRF) and X-ray diffraction (XRD). Additionally, the microstructure of RHA was analyzed through scanning electron microscopy (SEM). RHA obtained at different incineration temperatures was utilized into the base asphalt as an additive to produce rice husk ash modified asphalt (RHAMA), and the high and low temperature performance, temperature sensitivity and creep recovery of RHAMA were evaluated by the dynamic shear rheology (DSR) test, the bending beam rheology (BBR) test, and the multi-stress creep recovery (MSCR) test. These results were combined with microscopic analyses of RHA to assess the impact of incineration temperature on the performance of RHAMA. The findings reveal that when the calcination temperature exceeds 600 ℃, the amorphous SiO2 in RHA transitions to a crystalline phase. The incorporation of RHA enhances the high temperature performance and creep recovery of the base asphalt but reduces its temperature sensitivity and low temperature performance. As the incineration temperature of RHA increases, the high temperature performance and creep recovery of RHAMA decline, while temperature sensitivity and low temperature performance improve. The optimal calcination temperature for RHA is 600 ℃, at which the amorphous SiO2 content is maximized, resulting in the most significant improvement in the performance of the base asphalt.