Experimental Study On Mechanical Properties Of Industrial Recycled Steel Fiber Reinforced Concrete At High Temperature

Fire accident has become one of the main causes of building collapse accidents.Due to poor fire resistance of concrete,the mechanical properties of concrete are reduced after high temperature.Therefore,domestic and foreign scholars have done a lot of research on the decay law of basic mechanical properties of concrete after high temperature.With the rapid development of China’s automobile industry,a large number of waste tires need to be disposed every year,the recycled steel fiber extracted from waste tires is mixed into concrete,the high temperature resistance and good thermal conductivity can improve the mechanical properties of concrete after high temperature and improve the residual strength of concrete after high temperature.Therefore,adding steel fiber to improve the fire resistance of concrete has become a hot topic in the field of civil engineering.In this paper,industrial recycled steel fiber reinforced concrete and ordinary concrete without recycled steel fiber are taken as the analysis and research object.The concrete cube was heated by means of resistance furnace for 3 h at a specified temperature and high temperature.After the specimen was naturally cooled,the concrete specimens after high temperature were uniformly and continuously loaded,strength test of industrial recycled steel fiber reinforced concrete at high temperature with different content(0%,0.5%,1%,1.5%,2%).The variation law of crack width,compressive strength,split tensile strength with different temperature and different content of recycled steel fiber concrete after high temperature was analyzed synthetically.By observing the macroscopic phenomenon of concrete,the mechanical properties of industrial recycled steel fiber reinforced concrete at high temperature are discussed.The finite element analysis software ABAQUS is used to simulate the temperature field and temperature stress of steel fiber reinforced concrete after high temperature.The main conclusions of the test are as follows: the degradation process of mechanical properties of ordinary concrete and recycled steel fiber concrete after high temperature is analyzed,industrial recycled steel fiber concrete improves the compressive strength of concrete and increases the residual compressive strength of concrete.In particular,it can obviously improve the tensile strength of concrete at high temperature.It was found that the higher the heating temperature,the faster the strength of concrete decreased after the concrete was heated at a high temperature.In summary,the mechanical properties of concrete after high temperature will gradually decrease with increasing temperature.When the same temperature is raised,the mechanical properties of concrete mixed with industrial recycled steel fiber are obviously better than that of plain concrete at high temperature,and the recovery of steel fiber is helpful to improve the compressive strength and split tensile strength of high-temperature concrete.The mechanical properties of industrial recycled steel fiber reinforced concrete at high temperature are studied in this paper.It can lay a foundation for the recovery of high temperature characteristics of steel fiber reinforced concrete in the future,for the recovery of steel fiber reinforced concrete in the actual engineering application provides guidance,to industrial recycling of steel fiber reinforced concrete composite provide reasonable Suggestions for recycling,for provides theory basis for the identification of structures after fire.