Research On Mechanical Property Of New Bamboo Reinforced Concrete Flexural Member

Reinforced concrete structure has superior performance.However,excessive use of steel need consuming non-renewable iron resource and causes great damage on ecological environment.Therefore,scholars are seeking more economical and environmental alternative material of steel bar.Bamboo attracts a lot of attentions because of its high tensile strength and rapid regeneration.Researches showed that unprocessed bamboo can improve the loading capacity of concrete flexural member.However,there still exists some shortcomings,such as poor bond between bamboo and concrete,strength discreteness,low elastic modulus,perishable and easy swell-shrink.Furthermore,the failure mode of member is brittle fracture,which is dangerous to structure.Therefore,scholars did much work and proposed some solutions.To some extent,these solutions can overcome some deficiencies,but it is not ideal for the overall shortcomings.In this paper,some new solutions are proposed and experimental researches are carried out on basis of existing research results.Main works are shown as follow:(1)To overcome poor bond between bamboo and concrete,several processed bamboo bar are proposed and then experimental researches on bamboo reinforced concrete flexural members with different processed and reinforcement ratios are carried out.The results show that the effective bonding between bamboo bar and concrete can be ensured after bamboo bars are processed by proper methods.The failure modes of bamboo reinforced concrete beams are brittle fracture.For safty,normal section must design by the failure mode of concrete crushing.(2)Aiming at the problem of strength discreteness,low elastic modulus and easy swell-shrink,a method of producing composited bamboo cable used in bamboo reinforced concrete is presented based on the idea of composited bamboo cable.And then experimental researches on it are carried out,including strength test,swelling test and the bending test of flexural members.The results show that composited bamboo cable has higher tensile strength,lower strength discreteness and better performances of waterproof and anti-corrosion Compared with ordinary bamboo bars.What is more important is that it can greatly improves the elastic modulus of bamboo and decreases the deformation of structure.(3)To overcome the shortcomings of insufficient section stiffness and brittle fracture,a new concrete flexural member are proposed based on the analysis about composite of structure design load,which is called bamboo&steel combinational reinforced concrete.Then Experimental researches on bamboo&steel combinational reinforced concrete beams with different composited ratio of bamboo and steel are carried out.The results show that bamboo&steel combinational reinforced concrete flexural member not only greatly reduces the amount of steel bars,but also retains the main properties of steel reinforced concrete,like ductility damage.it has overcome the disadvantage of ordinary bamboo reinforced concrete.(4)The finite element model of different bamboo reinforced concrete flexural members are established by using ABAQUS software and the reliability of model are verified by the expeimental results.Then based on accurate model mechanical properties of members are studied effecting by different section,concrete grade and the ratio of bamboo&steel composited bar.The results show that resaonable secion high can reduce the deformation of members,but improving concrete grade has no significant effect.The failure pattern and mechanical property of bamboo&steel combinational reinforced concrete flexural member is related to reinforcement ratio.(5)Researches on bearing capacity calculation and deformation of bamboo reinforced concrete beams are carried out based on that bamboo bars can collaborative work with concrete.The results show that the caculation results of proposed method are in good agreement with experiment and finite element simulation.