Evaluation of the use of fine recycled concrete aggregate in concrete
Collaborator(s): Building and Construction Authority
Project Completion: Mar 2015
- To ensure that the fine recycled concrete aggregate (RCA) complies with the relevant standards/specifications
- To formulate the mix designs for concrete containing up to 100% fine RCA
- To comprehensively evaluate the concrete with various fine RCA replacement levels
Recycled concrete aggregate (RCA) is produced from the processing of construction and demolition waste. Though the use of RCA in concrete has been widely studied all over the world, most of the research works have predominantly concerned the viability of replacing natural coarse aggregates (i.e. the particle size in the range of 4mm to 20mm) with coarse RCA while the substitution of natural concreting sand with fine RCA (i.e. the particle size below 4mm) is less preceding. In an attempt to widen the applications of RCA, Samwoh has initiated a research study to address the concerns of using fine RCA in concrete.
In this study, extensive conformance and performance testing have been conducted to determine the suitability of fine RCA for concrete applications. Largely, it is able to satisfy the general requirements for fine aggregate in concrete production, except that it is much lighter and more absorptive than natural concreting sand. In view of these differences, adjustments have been made to the design mixes in order to maintain the yield and to achieve the desired workability.
As comparing with the concrete containing natural concreting sand, the overall integrity of the properties of concrete produced with fine RCA was being preserved when the replacement levels were kept low. In summary, it is feasible to incorporate fine RCA in concrete which offers economical and environmental benefits.