Durability of Geopolymer Mortar and Portland Pozzolan Cement (PPC) Mortar against Sulfuric Acid

Abstract

The manufacture of cement is often criticized to produce high CO2 emission to environment. Reducing cement in construction is believed to be the solution for better environment. Portland pozzolan cement (PPC) is known as a more environmentally friendly cement which substitutes some portion of cement clinkers with pozzolanic materials such as fly ash. Another material which is considered as green material is Geopolymer. The purpose of this study is to investigate the durability of mortars made of PPC and geopolymer in the corrosive environment. The geopolymer mortar was made of fly ash with 25% white soil substitution, and also 8M NaOH and Na2SiO3 as activators. The corrosive condition was simulated by Sulfuric Acid solution (H2SO4) with a pH of 4. The durability of the two types of mortar was investigated by testing their compressive strength, direct tensile strength, porosity, density and the changes of mass and physical shapes after immersion. The results show that the immersion of the mortars in a solution of pH 4 sulfuric acid does not make any major effects on the performance of the PPC mortar. However, the performance of geopolymer mortar with 25% white soil substitution decreases after being immersed in sulfuric acid solution.