Gypsum dehydration in cement and its impact on air-void structure in air-entrained concrete

摘要

The compatibility of the admixture of cement and concrete is an important factor in the creation of high-quality concrete. Common problems involving the resistance of concrete to freezing and thawing drew the authors' attention to gypsum dehydration in cement. The influence of gypsum dehydration on the air-void structure of air-entrained concrete obtained with cement low in C(3)A was examined. In all studied cases, the negative influence of gypsum dehydration was observed. It is believed that greater solubility and a higher solubility rate of hemihydrate result in higher early-stage Ca2+ and SO42- ion concentrations, and thus cause alterations in the chemical admixture's mechanism of action. (C) 2019 Elsevier Ltd. All rights reserved.