Open Access

ARTICLE

Influence of Erosion Induced by NaCl on the Mechanical Performances of Alkali-Activated Mineral Admixtures

by Jing Yu¹, Jie Ren², Guangming Shen³, Weixiang Sun², Hui Wang^4,*

1 Department of Architectural Engineering, Ningbo Polytechnic, Ningbo, 315000, China
2 Technology and Performance Management Department, China Construction Infrastructure Corp., Ltd., Beijing, 10029, China
3 Chief Engineer’s Office, Jiuzhou Engineering Design Co., Ltd., Zhengzhou, 451162, China
4 School of Civil Engineering and Geographic Environment, Ningbo University, Ningbo, 315000, China

* Corresponding Author: Hui Wang. Email:

(This article belongs to the Special Issue: Advances in Solid Waste Processing and Recycling Technologies for Civil Engineering Materials)

Fluid Dynamics & Materials Processing 2023, 19(9), 2385-2398. https://doi.org/10.32604/fdmp.2023.027877

Received 22 November 2022; Accepted 20 February 2023; Issue published 16 May 2023

Abstract

In this paper, the influence of NaCl freeze-thaw (F-T) cycles and dry-wet (D-W) alternations on the flexural, compressive and bonding strengths of alkali-activated fly ash (FA) and a blast furnace slag powder (BFS) is investigated. The considered NaCl concentration is 3%. The effect of polypropylene fibers on the mechanical strengths is also examined. Scanning electron microscopy (SEM), thermogravimetry (TG) and X-ray diffraction (XRD) are selected to discern the mechanisms underpinning the NaCl-induced erosion. The obtained results indicate that the best results in terms of material resistance are obtained with admixtures containing 60% BFS and 40% FA in terms of mass ratio and 3% polypropylene fibers in terms of volume ratio. The maximum rates of decrease of the flexural, compressive and bonding strengths after 300 NaCl F-T cycles are 21.5%, 20.3% and 22.6%, respectively. The corresponding rates of decrease due to NaCl D-W alternations are 28.1%, 26.1% and 31.5%, respectively. The TG curves show that the alkali-activating activity of BFS is higher than that of FA. Moreover, in the first case, the microstructure of the hydration products is more compact. The results also show that NaCl F-T cycles lead to increasing cracks in the alkali-activated BFS.

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Keywords

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