Sulfuric acid resistance of blended ash geopolymer concrete

This study presents an investigation into the durability of geopolymer concrete prepared using blended ash of pulverized fuel ash (PFA) and palm oil fuel ash (POFA) along with alkaline activators when exposed to 2% solution of sulfuric acid for up to 18 months. Ordinary Portland Cement (OPC) concrete was also prepared as control concrete. The main parameters studied were the evaluation of mass, compressive strength, products of degradation and microstructural changes. The deterioration was examined using X-ray diffraction (XRD), Fourier transform infrared (FTIR), thermogravimetry (TGA/DTG), scanning electron microscopy (SEM). The results of geopolymer and OPC concretes were compared and discussed. The performance of geopolymer concrete when exposed to 2% sulfuric acid solution for more than a year was superior to OPC concrete which is attributed to a more stable cross-linked aluminosilicate polymer structure formed in the geopolymer concrete.

► Geopolymer concrete prepared with blended ash (PFA + POFA), activated by alkaline solution and 1.5 year 2% H2SO4 exposure.
► The evaluation of acid resistance in terms of visual appearance, mass change and compressive strength was examined.
► The effect of H2SO4 investigated by XRD, FTIR, TGA/DTG, SEM.
► H2SO4 exposed geopolymer concrete was superior to OPC, due to more stable cross-linked aluminosilicate polymer structure.