Study On Basic Strength And Deformation Properties Of Steel Slag Aggregate Concrete

There is a huge amount of steel slag produced in China every year,but the recovery and utilization ratio of steel slag in China is only about 22%,which is far lower than the utilization rate of nearly 100% in developed countries such as Japan,Europe and the United States.Compared with ordinary stone,steel slag has higher density and compressive strength,and lower grindability index.Therefore,steel slag aggregate can be used in concrete instead of natural aggregate.The effect of steel slag on the appearance and chemical properties of concrete is also different.Baotou Steel Group produces a large number of steel slag every year.It is necessary to use steel slag to prepare concrete in this area,and systematically study its strength and deformation performance to help enterprises save energy and reduce emissions.In this paper,steel slag is used as aggregate to prepare concrete.Steel slag concrete is prepared by replacing coarse aggregate and fine aggregate with steel slag fine aggregate and steel slag coarse aggregate.The strength and deformation properties of steel slag concrete are studied experimentally and theoretically.The main research work is as follows:(1)The effects of steel slag fine aggregate and steel slag coarse aggregate on the mechanical properties of concrete such as cube compressive strength,splitting tensile strength and flexural strength were studied.The test results show that: steel slag fine aggregate and steel slag coarse aggregate can effectively improve the concrete strength,of which the steel slag fine aggregate concrete with 70% replacement rate has the largest strength improvement rate,and the steel slag coarse aggregate concrete with 50%replacement rate has the largest strength improvement rate;the steel slag fine aggregate has a higher reinforcement range than the steel slag coarse aggregate under each replacement rate.(2)The elastic modulus,toughness index,Poisson’s ratio and ductility of steel slag concrete are studied,The results show that the toughness index of concrete decreases first and then increases with the increase of steel slag fine aggregate replacement rate,and the toughness index is the minimum when the replacement rate is 50%;With the increase of the replacement rate of steel slag coarse aggregate,the toughness index of concrete continues to decline.(3)The influence of steel slag coarse aggregate and steel slag fine aggregate with different substitution rates on the stress-strain relationship of concrete under uniaxial compression is studied,The test results show that: the addition of steel slag coarse aggregate and steel slag fine aggregate can make the stress-strain curve of concrete present "high and thin",the rising and falling sections of stress-strain curve become steep,and the peak stress is greater.(4)Carreira and Chu model,Zhenhai model and T.H.Wee model were used to analyze the stress-strain relationship of steel slag concrete prism under uniaxial compression.The results show that the constitutive model of steel slag coarse aggregate concrete adopts the cross Zhenhai model,and the descending section adopts T.H.Wee model;the ascending section of steel slag fine aggregate concrete adopts Carreira and Chu model,and the descending section adopts T.H.Wee model.The fitting effect is good.The proposed constitutive model of steel slag concrete can better describe its uniaxial compressive behavior.