Study On Mechanical Properties Of Basalt-Polyvinyl Alcohol Hybrid Fiber Reinforced Concrete

Due to defects such as low tensile strength,poor toughness,and easy cracking,concrete materials have poor overall performance and durability problems.After the fiber modification,the performance of the concrete is improved,but due to the unitary nature of the fiber,the improvement of the concrete performance is often only one aspect.The emergence of hybrid fiber reinforced concrete solves this problem,and makes it possible for two or more fibers mixed into concrete to exhibit a good synergistic effect within a reasonable amount of content,to complement each other,complement each other,and improve the performance of concrete in many ways.In this paper,short-cut impregnated basalt fibers and polyvinyl alcohol fibers were used for single-blending and mixing.The work performance,mechanical properties and fracture performance tests of basalt fiber reinforced concrete,polyvinyl alcohol fiber reinforced concrete and basalt-polyvinyl alcohol hybrid fiber reinforced concrete were studied.The effect of fiber type,fiber content,and hybrid fiber composition on the performance of concrete was studied.The main findings are as follows:(1)The effect of hybrid fiber on the slump of concrete is greater than that of single fiber,and the effect of polyvinyl alcohol fiber on the slump of concrete is greater in the composition of hybrid fibers.(2)The effect of single fiber-doped and hybrid fibers on compressive strength of benchmark concrete is not obvious.The single-blended and hybrid fibers can improve the tensile strength of the benchmark concrete to a certain extent.When the fiber content is low,the hybrid fiber has a stronger effect on the tensile strength than the single-doped fiber,showing a good synergistic effect.Basalt fiber 2.6 kg/m3,polyvinyl alcohol fiber 1.3 kg/m3,tensile strength of 5.32MPa,an increase of 19.5%over the benchmark concrete.The hybrid fiber significantly improved the flexural strength of the benchmark concrete and the folding ratio of the concrete.The reinforcing effect was higher than that of the single-doped fiber.The hybrid fiber exhibited good synergy effect in the experimental range.Basalt fiber 2.6 kg/m3,PVA fiber2.6 kg/m3 flexural strength of 7.71 MPa,an increase of 29.1%over the benchmark concrete.In the composition of hybrid fibers,polyvinyl alcohol fibers have a great contribution to the improvement of the flexural strength of concrete.The addition of single-doped fibers and hybrid fibers changes the failure morphology of the reference concrete and destroys it as a ductile failure.(3)The reinforcing effect of hybrid fiber on the fracture toughness and fracture energy of concrete is higher than that of single fiber,showing a good synergistic effect.When the polyvinyl alcohol fiber is 2.6kg/m~3and the basalt fiber content is 5.2kg/m~3,the fracture toughness of the hybrid fiber concrete is 62.2%higher than that of the benchmark concrete,which is 31.8%higher than that of the single-mixed 2.6kg/m~3 PVA fiber concrete,10.7%higher than single 5.2kg/m~3 basalt fiber concrete.The breakage energy of hybrid fiber reinforced concrete is 461.9%higher than that of benchmark concrete,107.9%higher than that of single-mixed 2.6kg/m~3PVA fiber concrete,and 44.6%higher than that of single-doped5.2kg/m~3basalt fiber concrete.The reinforcing effect of basalt fiber on the fracture toughness and fracture energy of hybrid fiber reinforced concrete is more obvious.