Effects of Mg-Based Admixtures on Chloride Diffusion in Alkali-Activated Fly Ash-Slag Mortars

29 Pages Posted: 8 Jul 2024

See all articles by Jingxiao Zhang

Jingxiao Zhang

Guangzhou Metro Design and Research Institute Co Ltd

Yuwei Ma

Guangzhou University

Zuhua Zhang

Tongji University

Xiaocong Yang

Guangzhou University

Xingzhong Nong

Guangzhou Metro Design and Research Institute Co Ltd

Hao Wang

University of Southern Queensland

Abstract

This study evaluated the effects of various Mg-based admixtures, including magnesium oxide (MgO), layered double hydroxides (LDH), and calcined layered double hydroxides (CLDH), on the chloride resistance of alkali-activated fly ash-slag (AAFS) mortars. To this end, chloride diffusion tests were conducted on AAFS mortars containing 5 wt.% MgO, Mg-Al-CO3 LDH, and CLDH. The results revealed that all Mg-based admixtures investigated in this study enhanced the chloride resistance of AAFS mortars. The inclusion of MgO led to a finer pore structure and promoted the formation of more Friedel's salt, thereby enhancing the chloride resistance performance. Although the inclusion of Mg-Al-CO3 LDH and CLDH resulted in more lager pores in the matrix, leading to slightly lower compressive strength, the overall content of Mg-Al LDH and Friedel's salt formed in the system increased, which led to an improved chloride binding capacity and enhanced chloride resistance.

Keywords: Alkali-activated materials, Magnesium oxide (MgO), Layered double hydroxides (LDH), Calcined layered double hydroxides (CLDH), Chloride diffusion

Suggested Citation

Zhang, Jingxiao and Ma, Yuwei and Zhang, Zuhua and Yang, Xiaocong and Nong, Xingzhong and Wang, Hao, Effects of Mg-Based Admixtures on Chloride Diffusion in Alkali-Activated Fly Ash-Slag Mortars. Available at SSRN: https://ssrn.com/abstract=4888771 or http://dx.doi.org/10.2139/ssrn.4888771

Jingxiao Zhang (Contact Author)

Guangzhou Metro Design and Research Institute Co Ltd ( email )

Guangzhou
China

Yuwei Ma

Guangzhou University ( email )

Guangzhou Higher Education Mega Center
Waihuanxi Road 230
Guangzhou, 510006
China

Zuhua Zhang

Tongji University ( email )

1239 Siping Road
Shanghai, 200092
China

Xiaocong Yang

Guangzhou University ( email )

Guangzhou Higher Education Mega Center
Waihuanxi Road 230
Guangzhou, 510006
China

Xingzhong Nong

Guangzhou Metro Design and Research Institute Co Ltd ( email )

Hao Wang

University of Southern Queensland ( email )

P.O.Box 238 Darling Heights
Toowoomba, 4350
Australia

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