Effect of residual mortar on compressive properties of modeled recycled coarse aggregate concrete.

• Developed a FEA model for six-phase MRCAC. • Studied the influence of MRCA replacement rate and residual mortar thickness on compressive performance of recycled concrete. • Clarified coverage and adhesion amount of old cement mortar by statistical methods and analysis results. Based on the typical morphology of recycled coarse aggregate in reality and the ontological relationship of the existing recycled aggregate concrete (RAC) mesoscopic constituent materials, a finite element analysis model of recycled coarse aggregate that can take into account the factors of the amount and location of attachment of the residual mortar was developed to establish the Modeled Recycled Coarse Aggregate Concrete (MRCAC). Combined with the mesoscopic mechanical properties of MRCAC, a plastic damage intrinsic model was used in the numerical analysis of MRCAC under uniaxial compressive loading to study the damage characteristics and stress–strain relationships of MRCAC. In this paper, the Modeled Recycled Coarse Aggregate (MRCA) is established in the ABAQUS numerical analysis software by self-compiled Python script, and the uniaxial compression simulation of MRCAC is carried out. Compared with the existing idealized model recycled concrete and other forms of digital recycled concrete model, The results show that, on the premise of meeting the general law of existing research results, the development of cracks in MRCAC under load is directly related to the shape of residual mortar wrapping. The strength of MRCAC is minimally influenced by residual mortar adhesion amount; however, the coverage of residual mortar has a significant impact on its strength. The arrangement of MRCA may also play a role in the stress–strain relationship of MRCAC. Additionally, it should be noted that residual mortar adhesion amount and coverage are distinct concepts that affect the strength and strain of MRCAC independently. These findings highlight the need to differentiate between these two factors in further research. [ABSTRACT FROM AUTHOR]