Deformation Properties of Used Mortar and Recycled Brick Aggregate

In order to study the effects of the contents of used mortar recycled aggregate (OMRA) and brick recycled aggregate (BRA) on the deformation properties of recycled aggregate concrete (RAC),under uniaxial compression conditions,The RAC of OMRA (0%,5%,10%,and 15%) and BRA (0%,3%,6%,9%,12%,and 15%) were studied.The experimental results show that,under uniaxial compression,the interfacial relationships of RAC containing OMRA and BRA between different materials are more complex,and the failure mechanism is also more complex.The content of OMRA and BRA had significant influence on the deformation behavior of RAC.When the content of OMRA and BRA is high,it is difficult for existing formulas and models to accurately represent the actual value.In this study,the influence of OMRA and BRA content is taken into account,and the existing formulas for calculating concrete deformation are modified,so that these formulas can more accurately calculate the elastic modulus,peak strain and ultimate strain of recycled concrete.The stress-strain formula of Guo concrete fits the stress-strain curve of concrete very well.We modified the formula on the basis of Guo formula to make the formula more suitable for the stress-strain curve of recycled concrete containing old mortar and brick,and the theoretical model proposed has better fitting accuracy.The study provides a valuable reference for nonlinear analysis of recycled aggregate concrete structures under different proportions of OMRA and BRA.