Exploring vitamin-C as a retarder for calcium sulfoaluminate cement

Vitamin-C (VC), also known as ascorbic acid, is a water solvable vitamin and can be found in various plants. Its function as an essential nutrient for human being is well known and has been extensively studied. This study explores a novel application of VC as a retarder for calcium sulfoaluminate cement (CSA). CSA has gained significant research interest for its potential as a low-carbon alternative of ordinary Portland cement (OPC). However, CSA sets very fast, leaving very limited processing time. Experimental studies carried out in this study show that the setting times of CSA can be extended over five times by adding VC at only 0.5% of the weight of the cementitious material. More importantly, this addition of VC doesn't reduce the compressive strength of the produced mortar samples at 28d because their pore structure is refined by the added VC. The retarding mechanisms of VC on CSA can be attributed to both the surface adsorption and complexation with Ca2+.