Sulfate resistance and degradation mechanism of basalt fiber modified graphite tailings cement-based materials

This paper delves into the modification mechanism and deterioration mechanism of basalt fiber (BF) on the sulfate resistance of graphite tailings (GT) cement-based materials. Initially, the comprehensive properties of basalt fiber modified graphite tailings cement mortar (BFM-GTCM) under different sulfate cycles, such as apparent morphology, water absorption and mechanical characteristics were investigated. Subsequently, the relationship between the evolution of microstructure, interface stability, pore structure, chemical composition and functional groups of BFM-GTCM and its resistance to sulfate erosion under different cycles was revealed by various microscopic characterization and analysis methods (SEM/XRD/MIP/FTIR/DSI). Simultaneously, a corrosion coefficient-pore structure relationship model was also put forth based on multivariate regression theory, and the mechanism enhancing BFM-GTCM resistance to sulfate attack was investigated. The results demonstrated that a suitable blend of BF and GT can prevent sulfate ion penetration, significantly slow down the generation of corrosion products (AFt and gypsum) in cement mortar during sulfate attack, postpone the occurrence of new cracks and the growth of existing ones, improve pore structure, and significantly lessen the degree of durability degradation of BF-GTCM. Among them, 0.3% BF addition and 20% GT replacement was the ideal ratio. (c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).