Polyacrylonitrile Fiber Recycled Concrete Frost Durability Test And Damage Modeling Study

Abstract

The recycling of concrete is environment-friendly and contributes to the sustainable development strategy. Recycled concrete can achieve better compressive strength, but there are deficiencies in tensile and frost durability. Then, the polyacrylonitrile fiber can be used as a toughening component due to its good properties such as high tensile strength, high ultimate elongation, etc., which can endow the recycled concrete with higher toughness and maintain the properties of concrete under the high altitude and cold conditions. In this study, mechanical tests and frost durability tests were conducted on polyacrylonitrile fiber recycled concrete with polyacrylonitrile fiber mixing content of 0.7 kg/m3, 0.8 kg/m3, 0.9 kg/m3 and recycled coarse aggregate’s substitution rates of 30%, 40%, and 50%. The results showed that the concrete with the best frost durability is the one with 40% replacement of recycled coarse aggregate and 0.8 kg/cm3 of polyacrylonitrile fiber. Based on the experimental research, a freeze-thaw damage model of polyacrylonitrile fiber recycled concrete was developed, revealing the damage mechanism of polyacrylonitrile fiber recycled concrete. The results are of great significance in theory and engineering for the application of recycled concrete.