Mechanism of the Enhanced C4AF Sintering and Chloride-Binding Capacity Caused by Magnesium Doping

被引：0

作者：

Xue, Jiangwei ^{[1
]}

Li, Simei ^{[1
]}

Liu, Songhui ^{[1
]}

Ma, Xiaoe ^{[1
]}

Guan, Xuemao ^{[1
]}

机构：

[1] Henan Polytech Univ, Sch Mat Sci & Engn, Henan Key Lab Mat Deep Earth Engn, Jiaozuo 454150, Henan, Peoples R China

来源：

JOURNAL OF MATERIALS IN CIVIL ENGINEERING | 2024年 / 36卷 / 11期

基金：

中国国家自然科学基金; 中国博士后科学基金;

关键词：

Magnesium; C(4)AF; Density functional theory; C-3(A; F)H-6; Friedel's salt; LAYERED DOUBLE HYDROXIDE; PENETRATION RESISTANCE; CEMENT CLINKER; HYDRATION; MGO; EVOLUTION; BROWNMILLERITE; REACTIVITY; SURFACE; TIME;

D O I：

10.1061/JMCEE7.MTENG-17915

中图分类号：

TU [建筑科学];

学科分类号：

0813 ;

摘要：

This work examined the impact of Mg doping on the sintering, hydration, and chloride-binding capacity of C(4)AF minerals and elucidated the role of Mg doping on reactivity mechanisms by experiments and calculations. Rietveld analysis determined the solid solubility limit of Mg in C(4)AF is 1.6% by weight. By the density functional theory (DFT), it revealed Mg preferentially substitutes Fe sites, followed by Ca sites in C(4)AF. Increasing Mg doping up to 4% by weight enhanced the chloride-binding capacity of hydrated C(4)AF pastes by more than 50%, attributed to the increased formation of Friedel's salt. The introduction of Mg in C(4)AF promoted clinker sintering upon hydration and produced katoite, which reacted with chloride. Additionally, Mg facilitated the formation of layered double hydroxides that adsorb chlorides. The changes imparted by Mg doping served to increase microstructure porosity and optimize pore size distribution. The results provide insight into the role of Mg in high-Mg, high-Fe cement, demonstrating that C(4)AF phase change improves resistance to chloride intrusion. This has implications for the use of high-Mg limestone and the application of this cement in marine environments.

引用

页数：13