Experimental Study On Mechanical Properties Of Steel-PVA Fiber Reinforced Concrete

Fiber-reinforced concrete,as a new type of building material,has high strength,deformation ability and energy consumption ability.Mechanical properties and durability of the material can be improved by adding fibers.The fiber incorporation methods are mainly divided into one and multiple.There are certain disadvantages to the incorporation of a single fiber.For example,steel fibers with high elastic modulus have the ability to enhance the matrix,but there are problems such as high cost,poor durability and low elastic modulus.The addition of low elastic modulus fibers can have a toughening effect,but it will affect the strength of the matrix.In this paper,by mixing steel-PVA hybrid fibers,the advantages of the fibers are used to show the hybrid effect at different stages,and the basic properties and flexural toughness of the matrix are improved.Using experiments combined with theoretical analysis of fiber hybrid effects,the effect of steel-PVA hybrid fibers on the performance of matrix concrete is studied,and the optimal volume content of steel-PVA fibers is found.The main research contents and conclusions are as follows:(1)In order to study the influence of factors such as the strength grade of the base concrete and the volume ratio of steel-PVA hybrid fibers on the compressive strength,split tensile strength,and flexural properties of the concrete base,20 concrete test groups were used for research.The results show that the PVA fiber forms a similar web effect,and as a carrier of mixed steel fibers,the steel fibers are uniformly dispersed in the matrix.When blended with PVA fibers with a volume ratio of 0.75% and steel fibers with 1.25%,the hybrid fiber has the best reinforcement effect on the matrix.The compressive strength of the two strength grades of HFRC has been increased by 17.4%and 10.6%.In the split tensile strength test,adding an appropriate amount of fiber to the matrix can effectively increase the split tensile strength.Steel fibers with high elastic modulus have a greater impact on the split tensile strength.PVA fibers have a significant effect on the split resistance of concrete.The effect of tensile strength is small,and the single-doped steel fiber with a volume ratio of 2.0% can enhance the splitting tensile strength better than the hybrid fiber.(2)Steel-PVA hybrid fiber reinforced concrete beams are typical bending failures,showing ductile failure.When the total fiber volume content is 2.0%,adding a volume ratio of 0.75% PVA fiber and 1.25% steel fiber is optimal for mixing,and a good positive mixing effect appears,which greatly improves the flexural resistance and toughness of the substrate.ability.(3)When the total fiber volume content is 2.0%,the PVA fiber content is 0.81%and the steel fiber content is 1.19%,the C30 strength grade steel-PVA hybrid fiber produces the best hybrid effect;the PVA fiber content is C40 strength grade steel-PVA hybrid fiber with 0.72% and steel fiber content of 1.28% produces the best hybrid effect;both are the volume content of the fiber that best improves the flexural toughness.of the matrix under the current matrix strength grade.The fiber hybrid effect function can effectively make up for the shortcomings of the fiber spacing theory and the theory of composite material mechanics.At the same time,Matlab is used to fit a small amount of experimental data.The fiber hybrid effect function can be obtained by a more accurate method,which can accurately evaluate the best flexural toughness.of the substrate.It is possible to accurately evaluate the optimal fiber volume incorporation rate with improved matrix flexural toughness.