Research On Mechanical Properties And Sulfate Attack Resistance Of Steel Fiber Reinforced Ceramsite Concrete

Steel fiber reinforced ceramsite concrete(SFRCC)has advantages of high strength,strong corrosion resistance,the mixed steel fiber can effectively improve the mechanical properties and corrosion resistance of concrete.In this paper,the preparation of 0 ~ 3% steel fiber volume ratio,C30,C40,C50 concrete strength grade SFRCC;The steel fiber volume ratio on the mechanical properties SFRCC,selected the erosion by 5%,10% concentration of sodium sulfate solution,0%,25%,50%,the bending stress,dry-wet circulation factors such as concrete resistance to sulfate erosion experiment research.And the distribution of sulfate ion in concrete are simulated,and the main research results are as follows:Experiment shows that with the increase of steel fiber volume rate of ceramsite concrete compressive strength,flexural strength and splitting tensile strength has a different degree of increase,increase of compressive strength is limited,but the flexural strength and splitting tensile strength was bigger.Sodium sulfate solution erosion of concrete in the process of the main features include: early erosion,the solution of sodium sulfate into concrete,produce content makes concrete more compact,thus the flexural strength of concrete,the relative weight,relative move mould increases;During the period of erosion,with the accumulation of erosion products,the concrete expands and cracks,and the evaluation index continues to decline.At the later stage of erosion,the surface of concrete sloughed off,and the evaluation index decreased to the lowest level with time.Test found that incorporation of steel fiber can effectively enhance the concrete sulfate attack resistance,incorporation of steel fiber concrete product at a rate of 1% than the erosion resistance of the matrix concrete has obvious improvement,the incorporation of steel fiber volume rate was 2% and 1%,3% and 2% of the concrete specimen erosion resistance effects were small;The higher the strength of concrete strength,the stronger the resistance to sulfateerosion.Compared with long-term immersion in sulfate solution,concrete has a more serious damage degree than long-term immersion in sulphate solution.Bending stress can accelerate the erosion rate of sulfates on concrete,and it is becoming more and more obvious that the damage of concrete in the sulfate environment increases with the increasing of bending stress.Considering the influence of steel fiber,concrete strength and bending stress on concrete damage evolution,this paper establishes a three-index concrete damage model with strength resistance coefficient,relative weight and relative motion mode,and makes a preliminary prediction of the life of steel fiber ceramic grain concrete.Combined with engineering practice,it is shown that when the strength grade of concrete is C40,the prediction result is close to the engineering design life.Based on the second law of Fick,a free diffusion model of sulfate ion is established.On concrete test blocks by sulfate substance diffusion numerical simulation,the different time of concrete block sodium sulfate concentration in the process diagram and erosion depth.The results show that,with the increase of erosion time,the depth of sulfate ion erosion increases the numerical simulation results are in good agreement with experiment results,the sulfate erosion and damage evolution of concrete study has certain reference significance.