摘要：As an important aspect of concrete durability damage, sulfate corrosion has attracted more and more people's general attention. Studying the dura-bility of concrete against sulfate corrosion is condu-cive to ensuring the non-hazardous design of the concrete structure in the project, which is also very helpful to predict the service life of the project. This study simulates the corrosion characteristics of vari-ous sulfates on concrete under dry-wet cycle condi-tions through experimental methods, and studies the changes in the apparent characteristics, quality, de-formation, and strength of concrete as the corrosion time increases. Based on the principle of fracture mechanics, three-point bending specimens are used to analyze the change mechanism of concrete frac-ture parameters under corrosion time, and to obtain the sulfate corrosion depth of concrete.According to the sulfate corrosion test, compared with the test samples without sulfuric acid corrosion solution, the test samples immersed in sulfuric acid concentration of2.5%(A2.5 solution) and 10%(A10solution)are all eroded by sulfur ions. After 30d-300d immersion in A2.5 and A10 solutions, the change trend of axial compressive strength and splitting tensile strength is basically the same. The corrosion time of 60d is the turning point of the change in the compressive strength of concrete. After a 300d test process, the compressive strength and tensile strength of the con-crete in these two solutions are reduced to the lowest value. The compressive strength is 22.13 in the A2.5 solution and 21.13 in A10 solution, respectively, while the tensile strength is 1.83 in A2.5 solution and 1.81 in A10 solution, respectively. The changes of concrete axial compressive strength and splitting tensile strength with corrosion time are roughly the same,and both show a two-stage change pattern of first increasing and then decreasing. The difference is that the increase of the splitting tensile strength is at the initial stage ofcorrosion is smaller, but the de-terioration is more serious in the later stage of the corrosion, indicating that sulfate corrosion has a greater impact on the splitting tensile strength of concrete.
关键词：Freeze-thaw environment;sulfate corrosion;recycled con-crete;mechanical properties;damage study
