Experimental Study On Eccentric Compressive Behavior Of Full-size RC Columns Strengthened By Thin Layer Of RPC Reinforced Mesh Under Secondary Load

Reactive powder concrete reinforced mesh reinforcement method is a new method combining reactive powder concrete(RPC)and reinforcement mesh based on the design concept of reinforced mesh concrete outsourcing reinforcement method.-It not only has the advantages of obvious reinforcement effect of reinforced mesh concrete outsourcing method,simple construction process,and wide application environment,but also makes full use of the excellent mechanical properties and durability of RPC materials,so it has great research value and application prospects.-In order to better simulate and analyze the mechanical properties of the columns reinforced with reactive powder concrete reinforced mesh(RPCRM)in practical engineering,all specimens were designed as full-scale columns and reinforced under load,considering the influence of size effect.The eccentric compression test was carried out on one unreinforced comparative column and six RPCRM columns.The main results are as follows:(1)A total of 6 RPCRM full-scale eccentric compression columns and 1 reinforced concrete comparative column of the same specification were designed in the test,and the effects of the initial load level and the reinforcement ratio of the reinforcement layer on the reinforcement performance were analyzed.The results show that the bearing capacity and deformation capacity of the RPCRM columns are greatly improved,among which the maximum increase of peak load can reach 233%,and the maximum increase of displacement ductility coefficient is 155%.The increase ranges of both are related to the reinforcement ratio of the steel mesh and the initial load level.With the increase of the reinforcement ratio of the steel mesh,the peak load of the RPCRM column increases and the displacement ductility coefficient decreases;with the increase of the initial load,the peak load of the RPCRM column gradually decreases,and the displacement ductility coefficient increases.(2)Based on the experiment,the RPCRM column models were established for numerical analysis,and the simulation results were in good agreement with the test results.Twenty-seven specimens were established by the same modeling method.According to the simulation results,the effects of initial load,reinforcement ratio of steel mesh,the strength of RPC,and the concrete strength of the original column on the mechanical performance of RPCRM columns were further analyzed.(3)Referring to the calculation method of the secondary force eccentric column in the relevant specifications and literature,the calculation formula of the normal section bearing capacity of the RPCRM full-scale eccentric column under load is given through theoretical derivation.It can be used as a test basis for establishing reasonable reinforcement theories and methods,and provide a reference for the revision and improvement of relevant norms and standards.