Experimental Study On Shear Behaviorof B-P Hybrid Fiber Desert Sand Concrete Deep Beam

To solve the problem because of desert sand instead of ordinary medium sand preparation of desert sand concrete of the poor mechanical properties compared with ordinary concrete,improve the application range of the desert sand concrete member,in the desert sand concrete with hybrid fibers to join in the process of preparation,using fiber mixed to produce positive hybrid effect to improve the desert sand soil mechanics performance of concrete.Hybrid fiber desert sand concrete combines the advantages of desert sand concrete and fiber concrete,which not only meets the requirements of economic benefit and environmental protection in engineering construction,but also meets the requirements of mechanical properties of concrete members.At present,the research on B-P hybrid fiber desert sand concrete is relatively rare at home and abroad,and the related research on its shear performance has not been completed.In this paper,the influence law of hybrid fiber on the shear performance of desert sand concrete deep beam is studied with fiber type,fiber volume content and fiber hybrid ratio as the influencing factors.In this paper,basalt polyvinyl alcohol(B-P)hybrid fiber desert sand concrete is selected as the research object.Based on the fiber volume content,hybrid ratio and the type of the fiber produced 9 B-P hybrid fiber desert sand concrete deep beams,and the shear tests have been carried out,based on the test results analysis of the fiber volume content,hybrid ratio and fiber type on the B-P hybrid fiber at the beginning of desert sand concrete deep beam shear crack load,ultimate load,crack evolution and the influence of the load deflection curve.(1)The experimental results show that the working performance of concrete decreases obviously after the addition of fiber,and the slump of desert sand concrete decreases with the increase of fiber volume content;The working performance of ordinary concrete is better than that of desert sand concrete,while that of desert sand concrete with mixed fiber is worse than that of desert sand concrete with single fiber.(2)B-P hybrid fiber can improve the initial crack load and ultimate load of desert sand concrete deep beam.Through load-deflection curve analysis,the deformation capacity of B-P hybrid fiber desert sand concrete deep beam is better than that of desert sand concrete deep beam.(3)The addition of fiber can significantly improve the crack resistance of desert sand concrete members,and B-P hybrid fiber has better crack resistance than single fiber.At the same time,the fiber has a significant inhibitory effect on the development of cracks in the component,and the analysis of experimental data shows that the fiber also has a significant inhibitory effect on the increase of internal damage variables in the component.(4)Combined with the calculation formulas of the shear capacity of deep beams in domestic and foreign codes,the applicability of each code for the calculation of the shear capacity of deep beams in this test was discussed.The results show that both ACI318-11 code in the United States and GB50010-2010 code in China have good compatibility for the shear capacity of deep beams with fiber desert sand concrete.Based on the GB50010-2015 code in China and considering the reinforcing coefficient of hybrid fiber,a correction formula for the shear capacity of B-P hybrid fiber desert sand concrete deep beam is established.The formula fits well with the test value,which provides some reference for the application of sand concrete in engineering technology.