Mechanical Properties of Hydrochloric Acid Corroded Concrete Under Cyclic Loading

Most of the existing studies on acid corrosion of concrete focus on the mechanical behavior of concrete structures without loading or under monotonic loading.In order to study the variation law of mechanical properties of in-service concrete members under cyclic loading, six groups of concrete prism specimens were prepared and immersed in hydrochloric acid of 1%(mass fraction)for accelerated corrosion.The monotonic and cyclic axial compression loading tests were carried out to examine the influence of corrosion on the mechanical properties of concrete under cyclic axial compression loading. Then, the concept of effective load-bearing cross-area ratio was proposed, and the descending correction coefficient of effective load-bearing cross-area ratio was introduced to establish the practical constitutive model of hydrochloric acid corrosion concrete under cyclic loading.And the model was verified.The results show that hydrochloric acid corrosion has a significant effect on the failure characteristics of concrete. The surface of corroded concrete is easy to peel off under loading effects, and the area of spalling enlarges gradually with the increase of loading. Meanwhile, with the increase of corrosion period, the compressive strength reduces of concrete obviously, and the bearing capacity decreases rapidly. The envelope of stress-strain curve of concrete with different corrosion ages under cyclic loading is basically consistent with that of the monotonic loading.However, the degradation rate of descending section for the stress-strain curve of concrete under cyclic loading is larger than that under monotonic loading due to the accumulation of internal damage of corroded concrete, and the failure is relatively more prominent.The peak strain of concrete under cyclic loading is slightly less than that of the monotonic loading.As the continuing increases of the corrosion period, the peak strain and ultimate strain of concrete under cyclic loading increase observably, while the peak stress and elastic modulus decrease significantly.Compared with uncorroded concrete, the test peak stress and elastic modulus of corroded concrete decreases by 53.25% and 74.1%, respectively, and meanwhile the peak strain and ultimate strain increased by 55.7% and 77.87%, respectively.The stress-strain curves calculated by using the model established in this paper match well with the test results, indicating the desirable fitting effect of the model. © 2022, Editorial Department, Journal of South China University of Technology. All right reserved.