Cost and Carbon Emission Savings of Recycled Aggregate Concrete Made in Australia: A Case Study

Virgin concrete as the most common used construction material, leads to many adverse environmental issues which are urgent to be solved. Altering the virgin aggregate to the recycled ones produced from construction and demolition (C&D) waste is a promising way to mitigate the negative impacts of virgin concrete. Recycled aggregate concrete (RAC) benefits to recycle and reuse C&D waste, preserve raw materials, and lower the construction cost, while carbonation technology is introduced to enhance the mechanical performance of RAC. One kind of RAC product implementing carbonated RA into the mix design is named CO₂ Concrete, which has been examined to be very comparable with virgin concrete in mechanical properties. Therefore, this study aims to evaluate the cost and the carbon emission savings of RAC through a case study of CO₂ Concrete, addressing its 28 days compressive strength. It indicates that CO₂ Concrete has a great potential to be applied in practice as the mechanical, economic and environmental performances of some could surpass those of virgin concrete for the same mix design. The utilizations of carbonated RA, supplementary cementitious materials (SCMs) and chemical additives all contribute to overall better performance of RAC in terms of compressive strength, cost and carbon emission.