Synthesis and Characterization of Red Mud and Sawdust Based Geopolymer Composites as Potential Construction Material

Abstract

The aim of this study was to synthesize the geopolymer composites formed by two industrial wastes, namely red mud (RM) and saw dust (SD). SD was chemically treated with alkali for the removal of lignin and subsequently bleached, before forming composite with acid-modified RM. The composites were then characterized by using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetic analysis (TGA) and universal testing machine to study the morphology, chemical, thermal and mechanical properties. The FTIR spectrum showed that Si and Al from the raw materials played the major role in forming aluminosilicate geopolymer composites. The SEM images revealed that SD and RM particles aggregated to form fully condensed geopolymer matrices with high compressive strength of 8.3-138 MPa, which were comparable to Portland cement (compressive strength of 9-20.7 MPa).