Performance Test Of Steel Slag-sand Concrete

In recent years,the negative impact of the waste slag produced by the iron and steel industry has become more and more serious.The generation of waste slag not only greatly reduces the economic benefits of the steel industry,but also the accumulation of waste slag will occupy a lot of land,resulting in pollution of the natural environment.Therefore,in order to improve the situation of low utilization rate of waste residues in the steel industry as soon as possible,the recovery rate and reuse rate of the waste residues in the steel industry must be improved.This paper focuses on the feasibility of preparing C30 concrete with steel slag sand to replace fine aggregate,and conducts experimental research.C30 steel slag sand concrete was prepared by using steel slag sand to replace natural sand in ordinary concrete.Comparatively study the difference in the way of workability,mechanical properties and durability between steel slag sand concrete and ordinary concrete,obtain the best replacement rate of steel slag sand,and compare and analyze the economic benefits,and the following conclusions are obtained:(1)According to the slump test,it is found that steel slag sand instead of a fine aggregate has a certain adverse effect on the fluidity and workability of concrete.The higher the replacement rate of steel slag sand,the more disadvantageous it is to the fluidity and workability of concrete.When the replacement rate is 25%,the performance of steel slag sand concrete is closest to that of ordinary concrete.(2)On the basis of the tests of the cube compression,tensile,flexural,axial compression and elastic modulus mechanical properties it is found that the mechanical properties of steel slag sand concrete with steel slag sand to replace natural sand are slightly lower than ordinary concrete,except the compressive strength of the steel slag sand concrete cube with the replacement rate of 75% and the tensile strength,flexural strength,and axial compressive strength of the steel slag sand concrete with the replacement rate of 50%,the strength performance of other steel slag sand concrete could meet the specifications.And when the replacement rate of steel slag sand is 25%and 100%,the strength performance is closest to that of ordinary concrete.Considering the working performance and long-term expansion instability of steel slag sand concrete,it is recommended that the optimal replacement rate of steel slag sand is 25%.According to the elastic modulus test,when the curing age is 28 d,the elastic modulus ofsteel slag sand concrete is larger than that of ordinary concrete;and with the increase of the content of steel slag sand,the elastic modulus of concrete also increases.(3)The durability test shows that with the increase of the amount of steel slag sand,the carbonation resistance of the concrete tends to increase first and then weaken.The lower the resistance to chloride ion penetration is,the better the wear resistance is.When the replacement rate of steel slag sand is 25%,the resistance of steel slag sand concrete to chloride ion penetration and wear resistance is slightly lower than that of ordinary concrete,but its carbonation resistance is stronger than that of ordinary concrete.It is suggested that the optimal replacement rate of steel slag sand is 25%.(4)The economic cost analysis of steel slag sand concrete and ordinary concrete shows that the more steel slag sand is mixed into the concrete,the lower the production costs is,and the steel slag sand concrete has better economic and social benefits.(5)Comprehensive analysis of the working performance,strength performance and durability of steel slag sand concrete,the optimal replacement rate of steel slag sand is about 25%.