Effect of dry–wet ratio on sulfate transport-reaction mechanism in concrete. (4th October 2021)

• Record Type: Journal Article
• Authors: Wang, Kun; Guo, Jinjun; Yang, Lin
• Is Part Of: Construction & building materials. Volume 302(2021)
• Publication Date: 2021-10-04
• Subjects: Drying–wetting cycles -- Sulfate -- Ionic transportation -- Concrete -- Microstructure -- Durability; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2021.124418
• Languages: English
• ISSNs: 0950-0618

Abstract

Graphical abstract: Highlights: Chemical reaction and physical crystallization of sulfate in concrete are quantified. Chemical sulfate attack dominates ionic transportation under drying-wetting cycles. The most unfavorable dry-wet cycle parameter was determined based on sulfate transport behavior. Micromorphology of intermediate area and pore size distribution was determined. Abstract: Drying–wetting cycle accelerate the deterioration of concrete in aqueous sulfate environment, but their regime is not well-established. This study investigates the effect of dry–wet ratios (1:1, 3:1, 5:1, and 7:1) on the transport behavior and reaction mechanism of the sulfate in concrete. Concentrations of water-soluble and acid-soluble sulfates were measured via ion chromatography, and mineralogical alteration and microstructure characterization were investigated for auxiliary analysis to determine the most unfavorable dry–wet ratio. Results indicate that sulfate ionic transportation involves chemical reactions and physical crystallization, in which chemical sulfate attacks dominate the process, and the proportion of physical sulfate attacks gradually increase. Results reveal that the concentration of sulfate ions increases with the increase in dry–wet ratio. The dry–wet ratio of 7:1 is found to be the most efficient for promoting the inward transmission of sulfate ions. The implications of these results will provide the basis for the establishment of a unified drying–wetting cycle regime standard and durability research of concrete in corrosive environment.