Abstract

Incorporation of recycled concrete aggregates (RA) produced from construction and demolition wastes in concrete contributes to the sustainability from two perspectives: reducing environmental pollution and reserving natural resources by reducing the consumption of natural aggregates (NA). However, comparing to NA, RA has lower mechanical properties and higher water absorptivity due to the old mortar attached on RA surface, resulting in weakened interfacial transition zones (ITZs) in the concrete and the consequent reduced durability of concrete when RA was used to replace NA for producing recycled aggregates concrete (RAC). Therefore, extensive research work had been devoted to the enhancement of RAC performance and nanomaterials have demonstrated great potential in this regard. This paper reviews recent progress on the application of various nanomaterials for improving the microstructure as well as nano/mechanical properties of ITZs in RAC, and special attentions were given to the dispersion strategies for nanomaterials which determines the amount of nanomaterials required to achieve reliable improvement in RAC performance and thus the cost of using nanomaterials in RAC.