Research On Shear Capacity Of Desert And Sand Concrete Deep Beams Without Web Reinforcement

In order to alleviate the shortage of natural medium and coarse sand resources in Xinjiang,desert sand concrete can be formed by mixing the rich desert sand resources as part of the fine aggregate of concrete according to the mass ratio.In addition,the physical and chemical properties of desert sand in different areas are different,which have different effects on concrete How to apply the rich desert sand resources in Xinjiang to the construction still needs a lot of experimental research as support.In recent years,the research of desert sand concrete mostly focuses on the basic mechanical properties and ordinary component properties of desert sand concrete.Therefore,based on the research of desert sand concrete at home and abroad,this paper studies the mixture ratio of desert sand concrete and the shear bearing capacity of deep beams of desert sand concrete without web reinforcement,The main research work is as follows:With different water cement ratio,desert sand content and fly ash content as test variables,16 groups of mix proportion tests are designed and manufactured,and the influence rule of different factors on the compressive strength of concrete and the best mix proportion are obtained.The results show that with the increase of the content of desert sand,the compressive strength of desert sand concrete increases first and then decreases,and the appropriate amount of desert sand can effectively improve the compressive strength of desert sand concrete.The optimum mixture ratio is 0.45 water binder ratio,10%fly ash,20%desert sand,40%sand ratio and 0.45%water reducer.Based on the optimum mix ratio,the shear capacity of 8 deep beams without web reinforcement is studied.The influence of different shear span ratio,sand content and longitudinal reinforcement ratio on the failure mode and phenomenon of deep beams without web reinforcement,and the ultimate bearing capacity,cracking load and ultimate cracking load are studied by four point bending loading.The results show that the shear capacity decreases with the increase of shear span ratio.Adding desert sand can improve the shear bearing capacity of concrete deep beams.The test data of 8 deep beams of desert sand concrete without web reinforcement were collected and analyzed.The effects of different shear span ratio,desert sand content and longitudinal reinforcement ratio on load deflection relationship of deep beam members,load strain relationship of middle section of concrete span,load strain relationship of inclined section of concrete and load strain relationship of longitudinal reinforcement are studied.The results show that the deep beam of desert sand concrete without web reinforcement is similar to that of ordinary concrete and no longer conforms to the assumption of plane section.The "arching effect" of desert sand concrete deep beams has also been effectively developedThe existing calculation formula of shear capacity of ordinary concrete deep beams is no longer suitable for the calculation of shear capacity of desert sand concrete deep beams.Based on the test data and the calculation formulas of deep beam members in various countries,the theoretical calculation formula of shear bearing capacity of the deep beam of desert sand concrete without web reinforcement is put forward:Vn=1.105ψ(?)ftbwws sinθs.The calculation results are in good agreement with the test values.According to this formula,the calculation of the deep beam of desert sand concrete without web reinforcement has good security,economy and accuracy...