Harmonising life cycle sustainability thinking in material substitution for buildings

Abstract

Significant transition in the built environment will require an integrative and holistic application of Life Cycle Sustainability Assessment (LCSA) to accomplish a better understanding of shift in sustainability impacts across building life cycle phases. Nevertheless, there has been considerable difficulty in implementing life cycle sustainability thinking in buildings due to the complexity of harmonising the three dimensions of LCSA. This work, therefore, aims to monetise the key life cycle sustainability impacts of reinforced concrete and cross laminated timber (CLT) on a building project. This research undertakes a LCSA study based on cradle-to-gate system boundary to evaluate two alternative structural systems in an equivalent 5-star GreenStar-rated public infrastructure building project in Victoria, Australia. Hotspot analyses is conducted to ensure that indicators considered in the study represents up to 85% of the key life cycle impacts. Obtained results show that the overall life cycle sustainability impact of the original structural system ($ 3.02 million) reduced by more than half (i.e., 51%) by adopting the modified-CLT structural system ($1.55 million) in the case study project. Material substitution in building structural systems could provide a viable pathway in achieving net-zero emissions in Australia's built environment. Consequently, there is a compelling case to develop a holistic life cycle sustainability rating tool to enhance integrated design practice, improve resource utilisation and foster transparency in achieving life cycle sustainability in the built environment.