Experimental investigations on elasto-plastic behavior and fracture mechanism of ASR-damaged concrete

The crack patterns of alkali silica reaction (ASR)-damaged concrete vary depending on many environmental factors, and the damaged concrete with dispersed crack patterns shows a compressive behavior that differs from that of cracked concrete owing to external loads, not ASR damage, despite undergoing a substantial ASR expansion. Therefore, investigating the mechanisms governing the mechanical behavior of ASR-damaged concrete is necessary. Monotonic and cyclic compression tests were conducted on ASR-damaged concrete with ASR expansion and long-term storage conditions as test variables. The elastoplastic behavior and fracture progress of the ASR-damaged concrete were investigated, and crack propagation was observed using digital image correlation (DIC) measurements. The test results showed that the compressive strength, elastic modulus, and shear elasticity of the concrete tended to decrease with increasing ASR expansion. However, the fracture parameter representing the fracture progress of the ASR-damaged concrete resembled that of the undamaged concrete. This indicates that ASR-damaged concrete with dispersed crack patterns with small widths effectively transferred stress through friction between cracks despite undergoing a large tensile strain owing to ASR. In addition, when the specimen was stored under dry conditions rather than wet conditions for over one year, the elastic modulus, compressive strength, and shear elasticity—degraded by ASR— showed improvement, while the fracture parameter remained nearly unchanged.