Open Access

ARTICLE

Effect of Dry-Wet Cycles on the Transport and Mechanical Properties of Cement Mortar Subjected to Sulfate Attack

by Wei Chen^1,*, Weijie Shan¹, Yue Liang¹, Frederic Skoczylas²

1 School of Civil Engineering, Architecture and Environment, Hubei University of Technology, Wuhan, 430068, China
2 CNRS, Centrale Lille, UMR9013-LaMcube-Laboratoire de Mécanique Multiphysique et Multiéchelle, Université de Lille, Lille, F-59000, France

* Corresponding Author: Wei Chen. Email:

Fluid Dynamics & Materials Processing 2023, 19(3), 679-696. https://doi.org/10.32604/fdmp.2022.021249

Received 05 January 2022; Accepted 13 April 2022; Issue published 29 September 2022

Abstract

This study deals with the analysis of the detrimental effects of a “sulfate attack” on cement mortar for different dry-wet cycles. The mass loss, tensile strength, and gas permeability coefficient were determined and analyzed under different exposure conditions. At the same time, nitrogen adsorption (NAD), scanning electron microscopy (SEM), and X-ray diffraction (XRD) techniques were used to analyze the corresponding variations in the microstructure and the corrosion products. The results show that certain properties of the cement mortar evolve differently according to the durations of the dry-wet cycles and that some damage is caused to the mortars in aqueous solution. The pores fill with corrosion products, increasing the mortar specimen mass and tensile strength while reducing the permeability coefficient and pore size distribution. As corrosion proceeds, the crystallization pressure of the corrosion products increases, resulting in a 16% reduction in tensile strength from the initial value and a 2.6-factor increase in the permeability coefficient, indicating sensitivity to sulfate attack damage. Furthermore, the main corrosion products generated in the experiment are gypsum and ettringite. Application of osmotic pressure and extension of the immersion time can accelerate the erosion process.

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Keywords

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