Study On Shear Behavior Of Oblique Section Of SF-PVA Hybrid Fiber Self-compacting Concrete Beams

Fiber concrete and self-compacting concrete are two new and improved composite materials that have emerged in the construction industry in recent years.Hybrid fiber self-compacting concrete combines the advantages of fiber and self-compacting concrete.Applying it to the concrete matrix can improve the safety,stability and durability of the component.Therefore,in recent years,hybrid fiber self-compacting concrete has attracted the attention of experts at home and abroad.At present,there are relatively few studies on SF-PVA hybrid fiber self-compacting concrete at home and abroad,and the research on its shear performance is not perfect.Based on the Natural Science Foundation of Liaoning Province(2015020214),this paper takes the total fiber volume,mixing ratio and stirrup spacing as the influencing factors.Based on the test results,the shear performance of SF-PVA hybrid fiber self-compacting concrete beams is carried out.Experimental and theoretical research.In the experiment,12 SF-PVA hybrid fiber self-compacting concrete beams were fabricated according to the total fiber mixing ratio,mixing ratio and stirrup spacing.The shear performance test was carried out.The total fiber volume addition rate was analyzed based on the test results.The influence of the hybrid ratio and the stirrup spacing on the cracking load,ultimate load,load-displacement image and load-clamp strain image of the SF-PVA hybrid fiber self-compacting concrete beam.At the same time,three self-compacting concrete beams were added to the lower part of the beam,and the shear performance test was carried out.The cracking load and ultimate load of the SF-PVA hybrid fiber self-compacting concrete beam were analyzed only when the fiber was added to the lower part of the beam.And the effect of the load-displacement map.The test results show that SF-PVA hybrid fiber has better crack resistance than single fiber.SF-PVA hybrid fiber can increase the cracking load and ultimate load of oblique section;SF-PVA hybrid by load-deflection curve analysis The fiber self-compacting concrete beam has better deformation ability;when the volume fraction of PVA fiber is less than 0.5%,the shear force increases with the increase of the volume fraction of PVA fiber;when the stirrup spacing and fiber volume ratio are the same,the mixing ratio is 1: The shear capacity of the beam of 1 is the best;when the total volume fraction and the hybrid ratio are the same,the increase of the hoop ratio can significantly increase the shear capacity of the beam;only the lower part of the beam is mixed with the hybrid fiber and the beam with the full volume incorporated into the hybrid fiber.The cracking load has no effect and the ultimate load is only reduced by 8%.Based on the calculation model of shear capacity of fiber-reinforced concrete beams at home and abroad,the applicability of various bearing capacity models is discussed based on the experimental values of shear capacity test.Finally,the volume of PVA fibers is proposed in combination with the Technical Specification for Steel Fiber Reinforced Concrete Structures.When the rate is less than 0.5%,the calculation method of shear capacity of SF-PVA hybrid fiber self-compacting concrete beams.It provides a reference for the engineering application of SF-PVA hybrid fiber self-compacting concrete beam.