Evaluation of RCA concrete for the construction of Samwoh Eco-Green Building

Abstract

This paper describes a study conducted to evaluate the use of concrete containing up to 100% recycled concrete aggregate (RCA) for the construction of a commercial building known as the Samwoh Eco-Green Building in Singapore. The study is a continuation of research which established that concrete produced with RCA can achieve strength comparable to that of normal concrete produced with natural aggregate for structural applications by using a rational mix design approach. The present study was carried out to evaluate the effects of RCA on other engineering and durability properties of concrete, including compressive strength, flexural strength, tensile splitting strength, creep strain, water permeability, initial surface absorption, chloride ingress and sulfate resistance. With normal concrete serving as the basis for comparison, the experimental data showed that comparable compressive strength, flexural strength and tensile splitting strength were attainable for concrete containing up to 100% RCA. Although concrete with 100% RCA exhibited higher creep strain and initial surface absorption rate as well as lower resistance to water permeability, chloride ingress and external sulfate attack, the effects on the concrete performance are insignificant. On the whole, the research study suggests that RCA concrete can be designed to meet the specifications for structural applications, which led to the successful completion of the Samwoh Eco-Green Building.