Bituminous composite comprising amorphous silica from rice husks

Abstract

The composites were prepared with a ratio of bitumen to silica of 1:0, 1:1.5, 1:1.6, 1: 1.7, 1:1.8, 1:1.9 and 1:2 by weight, and calcined at the temperature of 150 °C for 6 hours. The structural and microstructural characteristics of the bituminous composites were examined by X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), Differential Thermal Analysis (DTA/TGA), and Scanning Electron Microscopy/Energy-Dispersive X-ray (SEM/EDX). Further evaluation was made by comparing the characteristics of the modified bituminous composites including the density, porosity, compressive strength, swelling thickness, and water absorption. The XRD study revealed that the major phases were silica and carbon amorphous, which were associated with the Si-OH, Si-O-Si and C-H functional groups according to the FTIR analysis. The DTA/TGA analysis resulted in an increase in the temperature decomposition by adding silica which was 230 to 315 °C. In addition, an increased silica addition was followed by an increase in the density, compressive strength, swelling thickness, and water absorption, while the opposite was true for the porosity. Based on these characteristics, rice husk silica has a positive effect on improving the mixture of high and low temperature performance, water stability, for use as a substitute in lightweight steel roof devices.