| Reactive powder concrete(RPC)is a new building material.Compared with ordinary concrete,RPC has many advantages,such as higher strength,durability,fire resistance,corrosion resistance and light weight.At present,RPC has been used in engineering buildings.There are few studies on the application of RPC in reinforcement field at home and abroad.In order to give full play to the excellent mechanical and physical properties of RPC materials,six eccentrically loaded columns are strengthened by RPC Section-Increasing method.The practicability of RPC material in the field of reinforcement and the reinforcement efficiency of RPC Section-Increasing method are studied through the mechanical properties of reinforced columns.RPC Section-Increasing method is a new type of reinforcement method.It not only retains the advantages of the wide range of applications inherent in the increased section method,but also incorporates the new characteristics of the RPC material,so it has extremely high research value and development prospects.The main contents of this paper are as follows:(1)Based on the initial experimental exploration of RPC materials,three groups of RPC laboratory mix ratios with theoretical strength of 100 MPa to 150 MPa were calculated by combining the full calculation method with the absolute volume method.Taking these three groups of calculated mix ratios as factor level tables and adopting orthogonal test scheme to carry out mix ratio test,the influence rule of water binder ratio,fly ash,silica powder,quartz sand,water reducing agent,defoamer and expander on compressive strength of RPC material and the importance order of each factor are obtained,and the optimum mix ratio of Mechanical properties of RPC is obtained preliminarily.(2)Based on the optimum mixing ratio of horizontal combination of factors obtained by orthogonal test,a single variable test scheme was adopted to further optimize the selected mixing ratio,and the influence of the content of each component on the compressive strength of RPC blocks with the age of 7 days and 28 days was analyzed.Finally,RPC materials with maximum strength of 117.64 MPa and 141.22 MPa were prepared under room temperature curing and 99 C water bath curing.(3)Six eccentrically loaded columns were strengthened with optimized RPC material and compared with one original column.The effects of two reinforcementschemes,one-side reinforcement and four-perimeter reinforcement,RPC thickness and reinforcement ratio on the failure load,cracking load and deformation performance of reinforced columns are studied.The influence of test parameters on the ultimate bearing capacity of reinforced columns is analyzed.(4)Using MIDAS/FEA finite element software to numerically simulate the reinforcement column and the comparison column,obtain the stress and strain cloud diagram of the simulated column and the failure load and crack distribution of the test piece,and combine the test results and simulation results to the test piece.The force state was analyzed in detail to verify the reliability of the reinforcement test.RPC Section-Increasing method can ensure the deformation coordination and reliable bonding performance between the reinforced layer and the original column,so that it can bear the load together,and ultimately improve the ultimate bearing capacity,crack resistance and structural stiffness of the reinforced column. |
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