A review on treatment techniques to improve the durability of recycled aggregate concrete: Enhancement mechanisms, performance and cost analysis

It is well-recognized that recycled aggregate (RA), obtained from dismantled structures, is more porous and less dense, than natural aggregate (NA) due to the presence of adhering cement mortar. Thus, the durability of concrete manufactured with RA, called recycled aggregate concrete (RAC), is inferior to that of natural aggregate concrete (NAC), thus limiting the use of the former on an industrial scale. This paper provides a state-of-the-art review on the durability properties, such as permeability, carbonation, reinforcement corrosion and shrinkage of RAC. The effect of factors influencing the durability of RAC are also discussed. Additionally, the treatment methods that can be used to improve the durability of RAC are critically reviewed, and possible mechanisms of improvement are highlighted. In addition, a comprehensive analysis of the cost of treating RA is carried out. Lastly, recommendations on future research are made. This review would be useful for researchers and engineers to select the optimal treatment schemes for improving the quality of RA and, consequently, the durability of RAC.