Pi Distribution method for numerical fracture analysis of reinforced concretes (RC) based recycled aggregates

A numerical investigation was carried out for both cases of cracked and uncracked reinforced (RC) and fibrous reinforced (FRC) /unfibrous concrete specimens incorporating recycled aggregate (RA), which were assessed to explore the failure properties of these materials, using the “Pi Distribution Method” (PDM). PDM is based on the non-random distribution of aggregates, which depends on the falling aggregate experiment. A finite element (FE) software (ABAQUS) is used to model the concrete specimens. The results demonstrate an improvement in the mechanical properties of concrete after adding RA. The incorporation of RA into the concrete results in an increase in elasticity and greater displacement at loading due to their important ductility, high porosity, and weak bond to the cement matrix. RA contributes to enhancing post-cracking behavior and stress redistribution. The elastic behavior of RA concrete shows a more horizontal load-displacement curve, indicating its deformability. Both concrete reinforcements, by bars and fibers, are analyzed in terms of Load-Displacement and load-CMOD (Crack Mouth Opening Displacement) for the notched specimen. The addition of steel fibers to RA contributes to the increase of the linear elastic stiffness before and at the maximal force of the specimens by acting as dispersed reinforcement. The efficiency of the proposed numerical FE mesoscopic model based on PDM is confirmed for all the study cases. This study opens new paths in the literature, explores many types of recycled aggregates and various fiber types, and considers other structural elements as beams, columns, and joints.