Steel Fiber-basalt Fiber High-strength Concrete Mechanical Properties And Crack Resistance

With the prosperity of the world economy,the wave of infrastructure has been set up around the world,and the landmark buildings on the tall buildings have been built in various cities.Many major projects have been built in various countries.These landmark buildings and major projects will place higher demands on concrete,requiring high concrete strength,good toughness,good fluidity,good corrosion resistance and impact resistance.Fiber concrete has been widely studied and applied in this context.Among them,steel fiber was firstly applied to engineering practice,and researchers have conducted in-depth research on it.Steel fiber has high fatigue resistance,tensile strength,ultimate bending strength,shear resistance and excellent impact resistance.The performance can significantly improve the deformation performance of concrete and is economical.However,steel fiber also has many insurmountable shortcomings,which are easy to rust,not resistant to acid and alkali,and self-important.The basalt fiber has good crack resistance,high temperature resistance,stable chemical properties,good mechanical and physical properties,and environmental protection.It is a new type of fiber for reinforcing cement-based composite materials,and the basalt fiber is resistant to acid and alkali corrosion and can increase.Basic mechanical properties of concrete.However,the price of basalt fiber is relatively high,and the performance of the basic mechanical properties is not as significant as that of steel fiber,especially the compressive strength.In this paper,steel fiber and basalt fiber were used as variables to study the effects of mixing two kinds of fibers on the strength and crack resistance of C60 concrete.The amount of steel fiber is 0.3%,0.6%,0.9%,1.2%,1.5%,and the amount of basalt fiber is 0.6kg/m3,1.6kg/m3,2.6kg/m3,3.6kg/m3,4.6kg/M3.The effect of both on the physical and mechanical properties and crack resistance of high strength concrete.The main contents and results of this trial are:1.Determine the mixing ratio of C60 concrete,and prepare a group of C60 plain concrete,steel fiber concrete with different contents,basalt fiber concrete with different contents and steel fiber-basalt fiber concrete mixed with different proportions.Make a comparison.The strength test was carried out 28 days after curing.2.The test data was analyzed and analyzed.It was found that the steel-reinforced fiber had a significant effect on the flexural strength and tensile strength of concrete.When the steel fiber content was 1.2%,the flexural strength and tensile strength increased by 64.1%.And 59.6%,but the increase in the compressive strength is not obvious.When the steel fiber content is 0.9%,the compressive strength is enhanced by 14.1%.The basalt fiber has almost no reinforcing effect on the compressive strength,and it will have an adverse effect on the compressive strength as the amount increases.but it has a significant reinforcing effect on the flexural and tensile strength of concrete,when the basalt fiber content is increased.At 3.6 kg/m3,the flexural and tensile strength enhancements were 29.1%and 25.3%,respectively.When the two fibers are blended,the reinforcement of the flexural and tensile strength of the concrete is more significant.When the steel fiber and basalt are 0.9%and 2.6kg/m3,respectively,the flexural and compressive strength is enhanced.The magnitudes are 87.5%and 73.3%,respectively.3.Single-steel fiber reinforced concrete(1.2%),single-doped basalt fiber(3.6kg/m3)and mixed steel fiber and basalt fiber concrete(steel fiber:1.2%,basalt fiber:3.6kg)were studied by ring test method./m3)The crack resistance of the three concretes is the optimum blending ratio obtained in the basic mechanical properties of concrete.According to the analysis and test data,compared with the plain concrete,the number of cracks in the concrete mixed with the fiber is smaller and the width is also significantly reduced,indicating that the proper amount of fiber can improve the crack resistance of the high-strength concrete.The effect of steel fiber on the crack resistance of high-strength concrete is less than that of basalt fiber.The crack reduction coefficient is 69.8%,the crack limit is grade 25 and the crack reduction coefficient of basalt fiber is 84.5%.Level one.The number and area of cracks in hybrid fiber concrete mixed with the optimum blending ratio are much lower than those of plain concrete.The crack reduction coefficient is 93.9%,and the crack limit is one grade.The reinforcement effect on concrete crack resistance is most significant..