Effect of amorphous rice husk silica addition on the structure of asphalt composite

Abstract

In this study, modified asphalt composites were produced by adding silica extracted from rice husk. The mass ratios of asphalt to silica are 1:0, 1:1.6, 1:1.8, and 1:2 and calcined at the temperature of 150°C for 6 h. The structural and microstructural characteristics of asphalt composites were examined by x-ray diffraction (XRD), Scanning Electron Microscopy/Energy Dispersive x-ray (SEM-EDX) Spectroscopy and Differential Thermal Analysis (DTA-TGA), respectively. The XRD study revealed that the major phases were carbon and amorphous silica. The surface morphology of asphalt without silica addition presents a cluster of larger size than the cluster of asphalt with an addition of silica. The addition of silica significantly increased the thermal stability of the asphalt due to the formation of a physically cross-linked silica network structure. DTA/TGA analyses produced that temperature decomposition increased with the increasing silica addition from 230℃ to 315°C. Based on these characteristics, the samples are considered for the roof material, suggesting their potential use in substitute lightweight steel roof devices.