Cyclic Loading Behavior of Concrete with Thermally-Induced Damage

The paper reports a study on concrete specimens that were subjected to constant amplitude, low-strain cyclic (LSC) and high-strain cyclic (HSC) tests to evaluate their cyclic behavior after they had been subjected to either ambient or elevated temperatures. Parameters examined included maximum normal stress, dynamic modulus, and extent of damage observed in specimens. An equation is proposed to help quantify the extent of damage in specimens, which accounts for both thermal and cyclic loading effects. Ultrasonic Pulse Velocity (UPV) measurements were also used to quantify the damage in both the LSC and HSC tests. Results show that losses in compressive strength and dynamic modulus are greater in cases with higher temperature exposures due to thermally induced damages. Also, cyclic characteristics of the specimens were found to be significantly influenced by the strain amplitude used in cyclic loading tests.