Mechanical Properties Of Steel Polypropylene Hybrid Fiber Reinforced Lightweight Aggregate Concrete

In the field of modern architecture,lightweight aggregate concrete is widely concerned by the engineering community in light of the excellent mechanical properties of lightweight aggregate concrete.The tension compression ratio,anti crack and anti permeability of lightweight aggregate concrete are better than that of ordinary concrete.However,the lightweight aggregate concrete also has the defects of high brittleness and low strength,and it is not conducive to the popularization and application.In order to overcome its own shortcomings,the researchers tried to mix all kinds of fibers in lightweight aggregate concrete to improve its mechanical properties.From the point of view of micro mechanics,the main factor that determines the mechanical properties of lightweight aggregate concrete is the strength of coarse aggregate in lightweight aggregate,and the interfacial strength between coarse aggregate and fine aggregate.The addition of fiber can make the cracks "bridge",and reduce the generation of micro cracks.Due to the widespread existence of the fiber,the internal concentrated stress can be released to improve the mechanical properties of lightweight aggregate concrete.In this paper,based on the research results of the steel fiber and polypropylene fiber reinforced lightweight aggregate concrete,the steel fiber and polypropylene fiber are selected and the main work is as follows:The orthogonal experiment was used to design 36 groups of steel polypropylene fiber reinforced lightweight aggregate concrete block and the 2 group did not add fiber blank specimen(compressive test group into 18 groups of steel polypropylene fiber reinforced lightweight aggregate block and the 1 group,the splitting tensile strength test for 18 groups of steel polypropylene fiber reinforced lightweight aggregate block 1 group and blank group).The test results of compressive strength and splitting tensile strength were carried out,and the variance analysis table of the ratio of compressive strength and splitting tensile strength was obtained.In the experiment,the influence of the compressive strength and the splitting strength factor and the corresponding factor are analyzed,and the linear relationship between the significant influence factor and the test result is analyzed,and the following conclusion is obtained:(1)For the cube compressive strength of steel polypropylene fiber reinforced lightweight aggregate concrete for the optimal ratio of steel fiber and steel fiber type corrugated shape to take the volume rate of 1%,polypropylene fiber volume fraction 0.9kg/m3,polypropylene fiber length diameter ratio is 167.(2)Through the variance analysis of factors influencing the compressive strength of hybrid fiber reinforced lightweight aggregate concrete cube effect from strong to weak as steel fiber shape,steel fiber volume ratio,the volume fraction of polypropylene fiber,steel fiber and polypropylene fiber interaction,polypropylene fiber length diameter ratio.(3)Steel polypropylene hybrid fiber lightweight aggregate concrete mixed with corrugated steel fiber,the cube compressive strength increased by 11%.(4)The splitting tensile strength of cube,steel polypropylene fiber reinforced lightweight aggregate concrete for the optimal ratio of steel fiber shape end hook type,the volume fraction of steel fiber,1.5%polypropylene fiber volume fraction 0.9kg/m3,polypropylene fiber length diameter ratio is 167.(5)Steel-poly hybrid fiber reinforced concrete splitting strength factors from strong to weak respectively form of steel fibre,polypropylene fiber volume fraction,fiber volume ratio,stiffness of steel fiber and polypropylene fiber interaction,polypropylene fiber length diameter ratio.(6)In splitting tensile strength test,the splitting strength of corrugated steel fiber is increased by 23%,and the splitting tensile strength of the mixed end hook type fiber is increased by 30%.(7)By linear regression analysis,the formula of the compressive strength and splitting tensile strength of steel polypropylene hybrid fiber reinforced lightweight aggregate concrete is as follows:F(cu,k)= 42.097-3.711×ρs-145xρf-1.917×ρl F(t,s)= 2.989+0.211×ρs+32.5×ρf-0.64×ρl...