Numerical Analysis of Damage and Deterioration of Recycled Aggregate Concrete Mixed with Glazed Hollow Beads after High Temperature

Purposes The internally porous and highly thermally stable glazed hollow beads (GHB) can reduce the high temperature damage and deterioration of concrete to a certain extent, and improve the fire resistance of concrete. In order to further clarify the mechanism of GHB in improving the fire resistance of concrete, starting from the meso-scale concrete, we proposed a modeling method for RATIC meso-scale model that can take into account the initial defects and the replacement rate of recycled coarse aggregate (RCA). Methods The effects of RCA replacement rates (0, 50%, 100%), GHB contents (0, 70%, 100%), and porosity (0, 2%, 4%) on the mechanical properties of RATIC after high temperature were explored by utilizing the plastic damage model commonly used at curent stage. Findings The results show that with the increase of fire temperature, the damage distributions of the RATIC specimens under load exhibit a gradually increasing trend, and the damage distribution of the specimens after 500 ℃ is more serious than that before 400 ℃. The addition of GHB alleviates the damage and deterioration inside the concrete to a certain extent, while the addition of RCA exacerbates this phenomenon. In addition, the strength of RATIC specimens gradually decreases with the increase of porosity.