Surface treatment on recycled coarse aggregates with nanomaterials

Surface treatment, using two slurries containing nanomaterials, was applied to recycled aggregate (RA). Experimental studies were conducted (1) to compare properties of RA before and after the surface treatment; and (2) to examine the modification effects of the surface treatment with nanomaterials on the microstructure and macroproperties of recycled aggregate concrete (RAC). The nanoindentation technique was used to achieve elastic modulus of different interface transition zones (ITZs) and old and new mortars in RAC. Test results show that both nanoslurries enhanced new ITZs between the old and new cement mortars. Although they did not work on old ITZs between the virgin aggregate and the old cement mortar, old mortars were surface strengthened. It is also proved that properties of both RA and RAC on the macroscale were improved by the surface treatment using nanomaterials.