Transformations in the reaction products and properties of carbonation-cured CSA cements exposed to a sulfate attack

Abstract

Reaction products and properties of carbonation-cured calcium sulfoaluminate (CSA) cements exposed to a sulfate attack were explored in an attempt to elucidate their durability aspects and potential opportunities for practical applications. CSA paste samples were either normally cured or carbonation-cured and subsequently immersed in a Na2SO4 solution. The test results indicated that carbonation curing hindered the delayed ettringite formation induced by a sulfate attack, especially in the carbonation-cured samples with an m-value of 0.5 or 1.0. In addition, these carbonation-cured samples exhibited less degrees of weight and mass loss compared to the normally cured samples. Given these test results, the carbonation-cured samples with an m-value of 0.5 – 1.0 were found to be the most durable against the Na2SO4 attack. The outcomes of this study can be viewed important as they provide a fundamental data source for developing guidelines on producing highly durable materials by combining mixture proportioning and carbonation curing when CSA cements are applied in areas particularly susceptible to sulfate attacks.

Keywords

• CSA cement
• Carbonation curing
• Sulfate attack
• Characterization