Magazine of Concrete Research, 2015, 67(12), 633–644 http://dx.doi.org/10.1680/macr.14.00212 Paper 1400212 Received 07/07/2014; revised 04/11/2014; accepted 17/02/2015 Published online ahead of print 11/04/2015 ICE Publishing: All rights reserved Magazine of Concrete Research Volume 67 Issue 12 Evaluation of RCA concrete for the construction of Samwoh Eco-Green Building Ho, Lee, Lim et al. Evaluation of RCA concrete for the construction of Samwoh Eco-Green Building Nyok Yong Ho Chief Operating Officer, Samwoh Corporation Pte Ltd, Singapore Yang Pin Kelvin Lee Senior Technical Manager, Samwoh Corporation Pte Ltd, Singapore Wee Fong Lim Technical Manager, Samwoh Corporation Pte Ltd, Singapore Keat Chuan Chew Group Director, Building & Construction Authority, Singapore Giau Leong Low Senior Manager, Building & Construction Authority, Singapore Seng Kiong Ting Deputy President (Academic) and Provost, Singapore Institute of Technology, Singapore 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. Notation e depth of water penetration in concrete (m) h hydraulic head (m) K coefficient of permeability (m/s) t p time under pressure (s) v fraction of the volume of concrete occupied by pores Introduction In response to the Singapore government’s call for sustainable development, there is a need to divert construction and demolition waste (CDW) away from landfill as well as an exigency to source alternative materials to replace natural aggregates, which are mainly imported from neighbouring countries. A feasible solution is to produce structural concrete using recycled concrete aggregate (RCA) derived from CDW. However, the use of RCA in concrete has been met with scepticism since it has long been challenged with an excessive volume of attached mortar and high porosity. Most studies in the literature have reported that compressive strength, flexural strength, tensile splitting strength and modulus of elasticity of RCA concrete decrease with an increase in replacement level of RCA (Casuccio et al., 2008; Hansen and Bøegh, 1985; Ting, 2004). Furthermore, some reports on RCA concrete have also cited 5–50% increases in creep and 20–70% increases in shrink- age (Limbachiya et al., 2000; Ravindrarajah and Tam, 1985). These features have restricted the use of high quantities of RCA in structural concrete applications. Previous studies (Ho et al., 2009, 2013) have shown that concrete made with RCA could be designed to produce comparable com- pressive strength and modulus of elasticity by adopting a rational mix design method in which natural coarse aggregate (NCA) was replaced with RCA (i.e. by mass of coarse aggregate) while keeping the water-to-cement (w/c) ratio constant with the addition of different amounts of water-reducing agent. This paper is a continuation of these studies, and describes laboratory tests carried out to determine the engineering and durability properties of concrete made with different replacement levels of RCA. The tests include measurements of compressive strength, flexural strength, tensile splitting strength, creep strain, initial surface absorption, water permeability and resistance to chloride and sulfate ingress. 633