Evaluation of Acid Resistance of Sustainable Binders Using Acid Consumption

Acid attack is a common problem in sewers, agro-food industries, and underground structures. Calcium aluminate cement (CAC) has been found to be a superior binder for sewer application because of its hydrated alumina-dominant phase assemblage. Calcium sulfoaluminate (CSA) cement, having aluminium hydroxide as one of the hydrated phases, is a potential candidate for the structures exposed to acidic environment. In addition, CSA cement is a low CO2 binder. The acid resistance of potential binders for the application in these structures can be evaluated by several conventional criteria, such as mass loss, dimension change, and strength loss. In some cases, these criteria fail to differentiate the binders. Additionally, contrasting results across the criteria have also been observed. Neutralisation capacity of the binders is an important factor affecting the acid resistance. Acid consumption method based on this factor can predict and differentiate the acid resistance of the binders. The acid resistance of CSA cement, CAC, and Portland cement (PC) was evaluated in terms of acid consumption of citric acid and sulfuric acid. The paper highlights a short-term test by which acid resistance can be evaluated within one day. The statistical significance of the results was analysed with ANOVA, student’s t-test, and correlation analysis.