Multiscale computational modeling of reinforced recycled aggregate concrete thermomechanical behavior

Abstract

This research project presents a proposal for a multiscale numerical analysis of concrete with recycled aggregates (RAC), which are obtained from the crushing of demolition concrete waste. The inedited proposed computational tool facilitates the evaluation of the thermomechanical behavior of the material, verifying the feasibility of its use for structural purposes. Better predictability of the behavior of this material would contribute to its greater use, which is still quite limited in Brazil compared to other countries. The RAC modeling in a more refined scale model (mesoscale) represents the heterogeneity and particular properties of the recycled aggregate. The fracture mechanisms that occur at the interface of the aggregate with the concrete matrix are influenced by these factors, introducing non-linearity to the mechanical problem. In this way, this work proposes the development of a mesoscale recycled concrete simulation tool with the consideration of the following phases: rock, new mortar matrix, old matrix and interfacial transition zones. Tension and compression damage model, thermal conductivity model and coupling model with loss of adhesion for steel reinforcements will be used, some of which are already properly implemented and others that will be implemented during the research. For this purpose, coupling and mesh fragmentation techniques with elements with a high aspect ratio will be used together. The models will first be used to study the thermomechanical behavior of recycled concrete, but they also constitute a tool for mesoscopic analysis of other concrete types such as high performance, with air incorporation and bars or fibers reinforced concretes, whose analysis may be carried out in some stages of the research. (AU)