Influence of Crack Patterns on Structural Performance of Reinforced Concrete Members Damaged by Alkali-Silica Reaction

Crack patterns affect the stress-transfer mechanism and thus have a significant impact on the structural performance of reinforced concrete (RC) members. The alkali-silica reaction (ASR) induces various crack patterns in concrete depending on the environment and confinement conditions, which makes it difficult to predict the structural performance of ASR-induced RC members. According to previous structural tests on ASR-damaged RC members conducted in Japan, localized cracks along the longitudinal reinforcing bars reduced the shear capacity of the RC members, whereas dispersed microcracks increased it, leading to ductile flexural behavior. The authors’ research team developed a mechanical behavior model for ASR-affected concrete in which the resistance of the ASR gel filling the cracks and crack patterns are considered. This study aims to analytically investigate the structural behaviors of RC members with different ASR crack patterns based on a mechanical model. RC members with localized cracks and dispersive microcrack patterns were simulated, and the analysis results showed distinctly different behaviors for the two crack patterns. In the RC members with microcrack patterns, stress was effectively transferred and the gel resistance increased, which significantly improved the shear capacity and ductility. However, in localized crack patterns with a large crack, the gel hardly resisted the stresses in the cracks, and the shear crack propagated more easily, leading to a reduction in the shear capacity. In addition, by comparing the analysis and test results, the analytical model accurately reproduced the shear capacity reduction of ASR-damaged RC members owing to localized cracks.