Mesoscale analysis for mortar deterioration during freeze-thaw modification of recycled coarse aggregate

Freeze-thaw modification of recycled coarse aggregate (RCA) is capable to remove the attached mortar efficiently, which can promote the usage of such eco-friendly recycled construction materials. To produce natural coarse aggregate (NCA) without introducing additional damage by this method, it is important to know the frost resistance of attached mortar in RCA. This paper presents a mesoscale analysis of mortar deterioration during freeze-thaw modification of RCA. The pore size distribution, pore pressure induced from ice formation, meso-scale constitutive laws are modeled and integrated with the discrete element method-Rigid Body Spring Model. The deformation during FTC, crack patterns and the mechanical behaviors are simulated with three typical types of RCA. Experiment results are also adopted to qualitatively show the effectiveness of such freeze-thaw modification. Finally, an empirical model to calculate the deteriorated mechanical properties of RCA is developed according to the numerical analysis.