Effects of Chloride Introduced Way and Metakaolin on Chloride Binding Capacity of Mortar

Abstract

Abstract: The same amount of chloride ions was introduced to mortars by simulated sea sand and mixed water respectively. The effects of chloride introduced way and metakaolin on chloride binding capacity were analyzed. And the corresponding test methods were used to analyze the different aspects: energy disperse spectroscopy (EDS) was conducted to analyze the distribution of chloride content; the change of hydration product was analyzed by X-ray diffraction (XRD) and derivative thermogravimetric method (DTG); the change of pore structure was evaluated by mercury intrusion porosimetry (MIP). The results show that there is a diffusion process of chloride ions from surface of sea sand to cementitious materials, and that chloride ions introduced by mixed water distribute evenly in mortar. The chloride binding capacity in mortar at different ages was discussed. The chloride binding capacity in mortar made with sea sand is lower than that made with mixed water at 1 d age, but these two chloride binding capacities tend to be same at 28 d age. The acceleration of metakaolin on early cement hydration reaction promotes the binding process of chloride ions introduced by mixed water. The content of Friedel’s salt and Ca(OH)₂ decreases with the increase of metakaolin content. The chloride ions introduced by mixed water has a better refinement effect on pore structure at 20% and 30% (mass fraction) metakaolin content.

Key words: chloride introduced way, metakaolin, chloride binding, Friedel’s salt, pore structure

CLC Number:

TU528

SUN Ming, SUN Congtao, ZHANG Peng, MA Fubin, LI Yantao, DUAN Jizhou. Effects of Chloride Introduced Way and Metakaolin on Chloride Binding Capacity of Mortar[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2021, 40(4): 1154-1161.

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