Experimental Study On Axial Compressive Behavior Of RC Columns Strengthened With RPCSM Under Load

With the continuous progress of Engineering Technology in China,buildings,highway bridges and other infrastructure have higher height,larger span and more complex structure,and the performance requirements of vertical force transfer member columns are more stringent.When the original column specimen is eroded and deteriorated,damaged by external force,the use of the original structure is changed,and the construction requirements are not up to standard,it needs to be repaired and reinforced to meet the design requirements.The traditional reinforcement technology is also facing new challenges.RPC is a cement-based composite with high strength,high toughness and low porosity.Its early strength develops rapidly,its components are close to and compatible with concrete,high compactness and good durability.Used in reinforcement and repair engineering,it can maintain the integrity of concrete system,replace steel and organic polymer reinforcement method,and overcome the problems of high price,poor bonding durability and limited improvement of bearing capacity.In order to improve the axial compressive performance of reinforced concrete(RC)columns under load,reactive powder concrete and steel mesh(rpcsm)is used to strengthen RC full-scale columns under load,which provides a new solution for engineering practice.Firstly,The paper discusses the research contents of domestic and foreign scholars.Secondly,seven RC square columns are designed and manufactured,including one unreinforced comparison column,one end stirrup reinforced column,two rpcsm reinforced columns and three end stirrup reinforced rpcsm reinforced columns.Considering the effects of reinforcement layer thick Ness,reinforcement ratio and end stirrup densification on the performance of axially compressed RC columns,experimental studies are carried out,and the failure mode,load deformation relationship and strain variation law of each specimen are analyzed.Then,The finite element analysis of RPCSM specimen is conducted by using ABAQUS software,the analysis outcomes are compared and verified,and the effects of reinforcement layer thick Ness and reinforcement ratio of reinforcement mesh on bearing capacity are analyzed.The simulation and test results show that the bearing capacity of the strengthened column is increased by 2.81～3.82 times;The interface between the original concrete column and RPCSM reinforcement layer is bonded reliably and works well together;With the increase of reinforcement ratio of reinforcement mesh,the thick Ness of reinforcement layer increases,the integrity of end stirrup is improved,the bearing capacity and axial deformation capacity are improved,but the ductility is reduced.Finally,based on the existing domestic and foreign codes and relevant theoretical research,considering the restraint effect of the reinforcement layer on the original concrete column and the improvement of the bearing capacity of direct vertical compression,the calculation method of the axial bearing capacity of rpcsm reinforced concrete column is proposed,which provides a theoretical basis for the practical application of the project and promotes the popularization of this reinforcement technology.