Study On Eccentrically Compressive Performance Of Recycled Concrete L-shaped Column

With the advance of the urbanization process,the demand for building materials is growing fast,which makes the natural gravel resources had been over-exploited.At the same time,the pollution of the natural environment caused by the large number of construction waste has become a problem that can't be ignored.Meanwhile,Recycled-concrete technology can effectively alleviate these problems,which has aroused the concern of scholars recent years.At present,Researchers had conducted extensive research on recycled materials at material,cross-section,component and structural levels,which mainly for rectangular or square cross-section,and less involved in shaped cross-section at the component level.Comparing with the ordinary cross-section column,the special-shaped column has the advantages of no edges and corners,and has been widely used in engineering practice.The combination of experimental and theoretical analysis had been used in the paper to analysis the L-shaped column of recycled concrete.The section hierarchy and component hierarchy had been taken into account.The main work and conclusions of this paper are as follows:(1)A type of recycled concrete L-shaped column with different regenerated coarse aggregate substitution rate was designed and fabricated,and bi-directional bias test were carried out.The results showed that the cross-sectional strain distribution conform to the flat section assumption,the deflection distribution of the column is approximately a sinusoidal curve,with the increase of the ratio of recycled coarse aggregate,the bearing capacity of the specimen decreased.Based on test results,the effect of regenerated coarse aggregate substitution rate,eccentricity,and load angle were considered,the analytical model of the L-shaped column of recycled concrete was established by ABAQUS.The results showed that with the increase of the ratio of recycled coarse aggregate,the bearing capacity of the specimen decreased,with the increase of the eccentricity,the bearing capacity of the specimen decreased,the variation load angle has little effect on the bearing capacity.(2)Based on test results,the calculation method of bearing capacity of normal section of recycled concrete L-shaped colmn is deduced,and the calculation program was compiled by MATLAB software.The effects of recycled coarse aggregate substitution rate,recycled concrete strength grade,reinforcement ratio,load angle and axial compression ratio on recycled concrete L-shaped columns were studied.The results showed that the higher the ratio of recycled coarse aggregate,the higher the bearing capacity of the specimen,the higher the strength grade of recycled concrete,the greater the bearing capacity,with the increase of the reinforcement ratio,the bearing capacity increase,the variation load angle has little effect on the bearing capacity,with the increase of the axial compression ratio,the bearing capacity decrease.(3)Based on test results,the calculation method of load-deflection curve of recycled concrete L-shaped column is deduced,and the calculation program was compiled by MATLAB software.The effects of the ratio of regenerated coarse aggregate,the grade of recycled concrete,the eccentricity,the load angle and the length of the column on the load-deflection relationship were studied.The results showed that the greater the replacement rate of recycled coarse aggregate,the worse the specimen ductility,the strength grade of recycled concrete has little effect on the deformation ability of specimen,the greater the eccentricity,the better the ductility of the specimen,the change of the load angle mainly affects the deformation distribution in the two eccentric directions,the larger the column length,the greater the deformation of the specimen.