Zhenguo Shi, M. Geiker, K. Weerdt
May 1, 2017
Citations
2
Influential Citations
192
Citations
Quality indicators
Journal
Cement and Concrete Research
Abstract
Abstract Chloride binding is investigated for Portland cement–metakaolin–limestone pastes exposed to CaCl 2 and NaCl solutions. The phase assemblages and the amount of Friedel's salt are evaluated using TGA, XRD and thermodynamic modeling. A larger amount of Friedel's salt is observed in the metakaolin blends compared to the pure Portland cement. A higher total chloride binding is observed for the pastes exposed to the CaCl 2 solution relative to those in the NaCl solution. This is reflected by the fact that calcium increases the quantity of Friedel's salt in the metakaolin blends by promoting the transformation of stratlingite and/or monocarbonate to Friedel's salt. Calcium increases also the amount of chloride in the diffuse layer of the C-S-H for the pure cement. A linear correlation between the total bound chloride and the uptake of calcium from the CaCl 2 solution is obtained and found to be independent on the type of cement blend.