Superior performance of calcium sulfoaluminate binders in extremely low-pH sulfuric acid exposure

• Acid resistance of CSA-based binder was evaluated in a low pH acidic environment. • The CSA(HY) binder used in this study outperformed PC binder in sulfuric acid environment of pH 0.5. • A novel titration-based method was used for assessing the acid resistance of cementitious binders. Evaluation of acid resistance of underground structural elements such as concrete pipes carrying industrial or domestic wastewaters is crucial to ensure their long-term durability. Compositional variability of cementitious binders affects the performance of concrete exposed to acidic environment. In this study, chemical resistance of calcium sulfoaluminate (CSA)-based binder and Portland cement (PC) are examined in low pH sulfuric acid environment. Based on the binders used in this study, CSA-based binder outperformed PC when exposed to sulfuric acid having pH of 0.5. A novel titration-based approach provided an accelerated method to monitor the acid resistance of different cementitious binders. The study shows how relative performance of PC and CSA based binder reverses when transitioning from high to low pH.