Environmental sustainability and cost performances of construction and demolition waste management scenarios: A case study of timber and concrete houses in Thailand

Circular economy (CE) is becoming a vital strategy to tackle two major environmental challenges of building and construction sector, viz., intensive resource consumption and massive construction and demolition waste (CDW) generation. The study assessed six circular economy scenarios for CDW management of concrete and timber houses in Thailand compared to the base case (landfill). Life cycle assessment and life cycle costing were conducted to illustrate the influence of CE strategies on environmental sustainability and cost performance. Material Circularity Indicator (MCI) was evaluated to determine the circularity performances of material use for the CE scenarios. The 100% recycling scenario resulted in 124% and 166-169% reductions of the mineral resource scarcity impact as compared to the conventional CDW management for the concrete and timber houses, respectively. For the concrete house, 100% recycling scenario resulted in the lowest life cycle costs (when combining both internal cost and externalities). On the other hand, the 100% recycling scenario of timber house would bring about the highest cost due to the energy cost. However, for the timber house, energy recovery scenario provided the lowest impact values on global warming, ozone formation, and terrestrial acidification. The internal costs of implementing the CE measures are higher for timber than for concrete. The MCI value for 100% recycling scenario was about 0.55; however, it can be increased to 0.73 (timber house) and 0.75 (concrete house) if the utility lifetime of building materials were extended. The results show the integrating the CE for CDW management can bring benefit to both environmental sustainability and cost performance.