Influence of pozzolanic materials on the hydration of calcium sulfoaluminate cements

摘要

Calcium sulfoaluminate (CSA) cements are receiving increasing interest because they promise to provide a low-CO_2 alternative to portland cement. In order to save costs and to further reduce the amount of CO_2 attributed to the production of CSA, they are often blended with supplementary cementitious materials (SCMs) such as limestone powder or industrial by-products such as slag or fly ash. In portland cement systems, pozzolanic SCMs react with portlandite to form C-S-H. In CSA cements this reaction path is not possible as portlandite is generally not present in the hydrate assemblage. In this contribution, thermodynamic modelling is used to assess how pozzolanic SCMs may contribute to the hydration reactions and change the hydrate assemblage of CSA cements. The calculated hydrate compositions are compared to experimental data proving that pozzolanic SCMs are able to contribute to the hydration reactions of CSA cements.