A feasibility study of using coffee cup waste as a building material - Life cycle assessment and multi-objective optimisation

Abstract

With the scarcity of land and rapid drive towards sustainable development, numerous research studies are conducted on diverting waste from landfills. However, majority of these studies are focused on either experimental investigation of material characteristics or environmental impacts. Due to heavy virgin material usage, building material manufacturing industries are increasingly interested in using waste materials to partially or completely replace virgin materials from building materials. The cost of production is still a governing factor in decision making process concerning sustainable green material procurement. Disposable coffee cups contain a plastic liner and annually 60,000 kg of coffee cup waste end up in Australian landfills. Therefore, the current study presents a LCA feasibility study focused on shredded coffee cup waste as sand replacement in concrete and wood chip replacement in particleboard manufacture. The results indicate that sand replacement in concrete can improve environmental impact savings as compared to particleboard manufacture. Sensitivity analysis demonstrated that percentage of sand replacement is highly sensitive to global warming potential (GWP) impact category and transport distance is highly sensitive to other environmental impacts. A multi-objective genetic optimisation is then conducted to obtain the cost-effective green mix designs for concrete samples. The results indicated that with 25% cost increase, emissions of CO2, NOx, CO and SO2 can be reduced by 10%, 38%, 2.5% and 43% respectively. These research findings are valuable for stakeholders determined to adopt cost-effective green building materials in their construction projects.