Residual Capacity and Permeability-Based Damage Assessment of Concrete under Low-Cycle Fatigue

Abstract

This study presents the residual capacity and post-event damage assessment of unconfined and glass-fiber reinforced polymer (GFRP)-wrapped confined concrete cylinders subjected to low-cycle fatigue loading. First characterized were monotonic compressive behaviors, including post-peak, strain-softening, and strain-hardening responses. Fatigue tests were then carried out at three stress levels to determine the number of cycles to failure, material degradation regarding the development of total and plastic strain, the deterioration of elastic modulus, and also the change in the temperature of test specimens. To assess the residual capacity of damaged concrete, the specimens were subjected to .3, .5, .7, and .9 of the fatigue life, and then monotonically reloaded to failure. After comparing the stress–strain curves of damaged and intact concrete, the remaining compressive strength and strain capacities were determined. Subsequently, permeability tests were conducted on concrete disks taken from damaged specimens, allowing the degradation process to be indirectly quantified using damage occurring in the concrete microstructure.