Fatigue life of plain concrete subjected to low frequency uniaxial stress reversal loading

Abstract

Most concrete structures sustain cyclic loading conditions during their service life. The accumulated damage caused by this type of loading can be regarded as fatigue and leads to sudden failures. Therefore, knowledge regarding the behavior of concrete under repeated loading is critical in structural design. It becomes even more critical when the fatigue stresses range from tension to compression. Since the fatigue behavior of plain concrete under cyclic sequential application of tension and compression, known as stress reversal, could differ from the behavior under pure tensile or compressive fatigue, concrete fatigue analysis under different cases of stress reversal is pursued in this study. A low frequency of 0.1 Hz is chosen for this study to replicate the slow recurring nature of certain loading conditions. Analysis indicates that stress reversal generally causes more severe deterioration and reduces the number of cycles to failure when compared to tensile fatigue. Results also indicate that adding some level of compression largely contributes to the energy that is required to fail the specimens under stress reversal fatigue. A macroscopic cross-section failure analysis is also followed in this research, revealing that specimens with highest concentration of fractured aggregates achieved longer fatigue lives.