Comparative analysis on costs and benefits of producing natural and recycled concrete aggregates: A South African case study

摘要

In this paper, comparative analysis of the costs and benefits of producing natural and recycled concrete aggregates for concrete works in South Africa was conducted. The study is based on generation of construction and demolition waste, which continues to escalate as a result of replacement and renovation of existing structures. Presently, most demolition wastes are dumped in landfills or used in low quality applications such as road-based construction etc. One of the mitigation measures employed, is the reuse of demolished concrete as recycled concrete aggregate. The present study shows that the net benefit of producing natural or recycled concrete aggregate, is negative. However, production of recycled concrete aggregates is less expensive than that of natural aggregates. For instance, the long-term cost of producing one tonne of coarse recycled concrete aggregate was about 40 % less than that for coarse natural aggregate. Also, the environmental benefit of producing one tonne of recycled concrete aggregate was approximately 97 % higher than that for natural aggregate. Hence, the commercial production of recycled concrete aggregates from waste concrete should be promoted as a cost-effective and environmentally beneficial approach for implementation in the construction industry.