摘要：In many areas in China, concrete buildings are often exposed to ocean salt corrosion and freeze-thaw environments, which poses threats to the dura-bility ofbuildings. Previous studies cannot fully con-sider the combined effects of salt corrosion environ-ment and freeze-thaw environment, and the further systematic research on the mechanical properties and damage mechanism of concrete buildings is still lacking. Therefore, the cyclic coupling effect of sul-fate corrosion and freeze-thaw is taken as the re-search background to achieve the purpose of provid-ing effective data support for the durability of recy-cled concrete. Through the mechanical performance test, the corresponding change law of the compres-sive strength ofrecycled concrete and the sulfate cor-rosion time under the sulfate corrosion environment is obtained. By using the scanning electron micro-scope and mercury porosimeter to detect the micro-scopic morphology and pore structure of recycled concrete under sulfate corrosion and freeze-thaw en-vironment, the microstructure of the recycled con-crete under different freeze-thaw times and different corrosion times are obtained. The research results show that:based on the mechanical performance ex-periment of recycled concrete, the relationship be-tween the mechanical performance parameters of mineral-blended recycled concrete under different freeze-thaw and different corrosion times is initially established. Through the microscopic test method of recycled concrete, the relationship between fine ap-pearance structure and macroscopic properties of re-cycled concrete is obtained. In the mechanical per-formance test,under the condition of freeze-thaw 30-90 times, while the sulfate corrosion process of 30d to 300d, the compressive strength gradually in-creases from the average value of 58.6Mpa. How-ever, after 300d corrosion, the compressive strength drops rapidly to an average value of 47.3Mpa, with an average decrease of 11.3%,indicating that under salt corrosion and freeze-thaw, its frost resistance and corrosion resistance are weakened. In the micro-scopic test of recycled concrete, the average pore size of the mixed recycled concrete after 300 days has increased by about 50nm compared with the value after 30 days. The pore structure of the con-crete has become significantly worse under the ac-tion of freeze-thaw and salt corrosion.
关键词：Freeze-thaw environment;sulfate corrosion;recycled con-crete;mechanical properties;damage study
