The Kinetics Role of Gypsum in Limestone Calcined Clay Cement Exposing to Sulfate solution by the Thermodynamic Study

Karkhaneh, Sama; Tarighat, Amir; Ghaffarpour Jahormi, Saeed

doi:10.22059/ceij.2025.379265.2096

The Kinetics Role of Gypsum in Limestone Calcined Clay Cement Exposing to Sulfate solution by the Thermodynamic Study

Articles in Press

Document Type : Technical Notes

Authors

Sama Karkhaneh

Amir Tarighat

Saeed Ghaffarpour Jahormi

Department of Civil Engineering, Shahid Rajaee Teacher Training University, Tehran, Iran

10.22059/ceij.2025.379265.2096

Abstract

In current research, the kinetics role of gypsum is evaluated during the sulfate attack by replacing cement with calcined clay and limestone. This study is done by geochemical code PHREEQC along with kinetics consideration. The results similarity of current and other studies indicates the accuracy of the simulation. Kinetics diagrams for samples with different cement replacement content, and calcined clay to cement replacement content ratios are evaluated to get more information about the kinetics path of gypsum production during sulfate attacks. The results show that three stages can be considered for the kinetics change of gypsum. The first stage of gypsum production gets longer as calcined clay to cement replacement content ratio increases. This means that gypsum is produced with delay for the mixture with a greater calcined clay to cement replacement content ratio. The availability of more aluminum ions as a result of greater calcined clay leads to the continuation of ettringite production instead of gypsum formation. In LC3 cement the maximum amount of produced gypsum is reduced as well as the rate of gypsum production. The stress due to the gypsum formation is applied to the cement matrix with delay because of the prolongation of first stage.

Keywords

Thermodynamics

Kinetics

LC3 cement

Sulfate attack

Gypsum

Subjects