A critical review on the durability of geopolymer composites in acidic environment

Abstract

Abstract Deterioration of concrete in acidic environments result in premature degradation in terms of microstructural alteration of phases leading to mass changes, weakening of mechanical properties, increase in porosity due to calcium leaching etc. Industries are found to dispose acidic effluents directly into the environment without proper treatments. Again, these acids can be organic as well as inorganic acids. Organic acids unlike inorganic acids are found to be weak acids due to their partly dissociative nature. The mechanism of acid attack varies based on the acid type and the characteristics of the calcium salt that are formed. Conventional concrete made with Ordinary Portland Cement (OPC) are not resistant to acids. Also, as we strive towards sustainable development, alkali activated or geopolymer concrete has started to gain attention as it is found to have better mechanical properties and durability comparing to conventional concrete. This paper reviews the damage mechanisms of sulphuric acid, citric acid, nitric acid and acetic acid on the alkali activated binders.