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Abstract

This study performs a comparative life cycle assessment (LCA) of two conceptual commercial office buildings – one using cross-laminated timber (CLT) construction and one using conventional cast-in-place concrete. The main goal is evaluating the differential environmental impacts of utilizing wood-based materials versus standard concrete and steel construction. The scope encompasses a cradle-to-grave assessment from material production through end-of-life disposal. The functional unit is 1 square meter of occupied floor space over a 60-year service life. The Athena Impact Estimator for Buildings software is employed to model the building life cycles using North American life cycle inventory data. Mid-point impact assessment of five key indicators (global warming potential, acidification, eutrophication, smog formation, ozone depletion) is carried out together with end-point assessment to estimate relative damages to human health, ecosystems, and resources. The material quantities for CLT panels, glulam columns, concrete slabs, reinforcing steel, and other assemblies are parameterized based on typical five-story office building specifications. The study finds that across most impact categories assessed, the CLT building exhibits 15-25% lower environmental impacts compared to the base case concrete building. Global warming potential is reduced by over 35% due to the carbon sequestration from biogenic CLT materials offsetting substantial process emissions from concrete production. Resource depletion and human health impacts are also lowered by using renewable wood products versus emissions-intensive concrete. However, certain tradeoffs exist, with concrete demonstrating modestly better performance for ozone layer depletion potential and marine aquatic ecotoxicity potential due to greater use of wood preservatives in CLT construction. Overall, the LCA indicates net environmental benefits and reduced emissions offered by increased use of mass timber as a green building material. Further assessment with uncertainty analysis is recommended to strengthen the robustness of these findings.

Course: Construction Project Management - MSc - C1659

Date Deposited: 2023-11-07

URI/permalink: https://library.port.ac.uk/dissert/dis14262.html