RESEARCH ON THE MECHANISM OF RECYCLED COARSE AGGREGATE'S INFLUENCE ON THE DURABILITY OF CONCRETE STRUCTURE

At present, China is the country with the largest scale of urban construction in the world, producing a large amount of waste concrete. In recent years, domestic and foreign experts and scholars have studied the basic physical properties and mechanical properties of recycled aggregate concrete. However, the strength value of the studied recycled aggregate concrete is relatively low, and the experience in actual engineering projects is also relatively low, which can only be used for non-load-bearing maintenance components, limiting the wide application of recycled aggregate concrete. There are still few studies on the durability of recycled aggregate concrete. Based on the strategic thinking of sustainable development and the needs of civil engineering construction, it is a general trend to apply recycled concrete, a new green building material, to civil engineering, especially structural engineering. Therefore, from the perspective of structural durability, this article studies the durability of recycled aggregate concrete under the requirements of high strength, including shrinkage, carbonization resistance, chloride ion penetration resistance, and sulfate corrosion resistance. Thereby, the development of mining resources can be reduced, the pollution pressure caused by the dust brought in the development process can be reduced, and the cost in the construction industry can also be reduced. The experimental results show that adding steel balls in the grinding step has a 9.3% lower shrinkage value than without steel balls. In the anti-sulfate performance, under the 5% concentration of sodium sulfate solution, the process of this subject can reach the KS90 level and meet the specified requirements.