Reviews of the performance and applications for recycled aggregate concrete

The use of recycled aggregate (RA) from construction and demolition (CandD) waste raises important environmental and construction engineering issues. RA has poor strength and high water absorption rates; therefore, recycled aggregate concrete (RAC) is rarely used in high-grade applications and only restricted for roadworks, sub-bases, pavements, retaining walls and footpaths. However, RAC can also lead to new possibilities for structural applications. In some countries, RA is used as coarse aggregate in new concrete in construction projects by carefully controlling its production process, such as Waldaspirale and Vilbeler projects in Germany. A two-stage mixing approach developed in Hong Kong has demonstrated that more than 20% strength improvement for RAC and reduction in strength variability can be achieved. This paper reviews the performance of RAC and the existing applications for RAC from literatures and pervious researchers. Recommendations to improve the quality of RA and RAC are also discussed.