National Natural Science Foundation of China (No. 52078068); Natural Science Foundation of higher education in Jiangsu province (No. 19KJB560007); Changzhou key R & D Program (Applied Basic Research) project (No. CJ20200079)
Based on the method of nitric acid accelerated dissolution, the comparative study on the corrosion resistance durability of natural aggregate concrete (NAC) and recycled aggregate concrete (RAC) prepared using 100% of recycled coarse aggregate (RCA) with different qualities (class I, class II and class III) is performed. The degradation law and damage mechanism of corrosion resistance of RAC are explored from the aspects of mechanical property degradation and internal micro-structure damage. The results show that the compressive strength of recycled concrete prepared by high-quality aggregate with better physical properties is higher, and there is a good correlation between them. In the corrosion environment, the compressive strength loss rate, mass loss rate and corrosion depth of recycled coarse aggregate concrete gradually increase with the increase of corrosion age, but not strictly increase with the decrease of coarse aggregate quality, and there are periodic differences in different periods. The SEM images show that the interfacial transition zone of low-quality aggregate concrete is obviously different before and after corrosion. According to the fitting formula of corrosion depth and corrosion time, the concrete prepared by three kinds of quality aggregate can meet the requirements of hydraulic structure in soft water environment, and the recycled coarse aggregate concrete with low quality (Class III) can be used for the hydraulic engineering structure with 50 years of service.