Effective utilization and recycling of mixed recycled aggregates for a greener environment

• Published in: Journal of cleaner production Vol. 236; p. 117600
• Main Authors: Zhang, L.W., Sojobi, A.O., Kodur, V.K.R., Liew, K.M.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-11-2019
• Subjects: Closed-loop construction and demolition waste management; Economics of recycling; Mixed recycled aggregates; Recycled fine and coarse aggregates; Sustainable construction; Taguchi-RSM optimization; Mixed recycled aggregates; Taguchi-RSM optimization; Closed-loop construction and demolition waste management; Sustainable construction; Recycled fine and coarse aggregates; Economics of recycling
• ISSN: 0959-6526; 1879-1786
• DOI: 10.1016/j.jclepro.2019.07.075

Both global warming issue and ozone layer depletion have triggered the awareness of the utilization of recycled materials in construction industry for a greener environment. The utilization and recycling of mixed recycled aggregates (MRA) comprising recycled fine aggregates (RFA) and recycled coarse aggregates (RCA) were explored for construction applications using the coupled Taguchi-RSM optimization approach. Under stringent durability requirements, 35% RCA combined with 6% RFA can be utilized while 70% RCA combined with 30% RFA under non-stringent conditions for non-structural applications. Our study also revealed large potential applications of pretreated mixed recycled aggregates in above-ground structural construction applications. Furthermore, review of literatures revealed presence of behavioral, technical, legal and market barriers which can be overcome through proposed measures. Our study also revealed a payback period of 3 years for recycling investments and revenue generation of HK$ 12 billion within the first ten years of operation and prevention of 20.9–50.1 × 106 KgCO2 equivalent emission annually. In order to achieve these benefits, a pragmatic, recycling-based closed-loop construction and demolition management approach is recommended to achieve a greener environment. Government should take active leading role towards CDW recycling through high-impact policy making and implementation.
•This study reveals behavioral, technical, legal and market barriers.•A closed-loop approach is recommended to ensure sustainable recycling.•Application of recycled aggregates in above-ground structures.•Recycled aggregates can be used in stringent and non-stringent applications.•Recycling is economically feasible and environmentally friendly.