Life cycle assessment of a low-height noise barrier for railway traffic noise

Abstract

Life cycle assessment (LCA) methodology was applied to assess five locally developed mix designs for a 20 m low-height noise barrier (LHNB) categorized as: precast Portland cement concrete (S0-baseline scenario), two precast geopolymer composites (S1; S2), and two additive-manufactured geopolymer composites (S3; S4). The objective of the study is to carry out a LCA study of the mix designs, to identify environmental hotspots and evaluate the influence of durability and service life on the LCA results. Environmental impact categories assessed are global warming potential (GWP), fossil depletion, photochemical ozone formation, and acidification. Results show that when a fixed service life of 40 years is chosen for all mix designs, S4 is the most environmentally sustainable with 73% reduced GWP when compared to S0. When sensitivity analysis was used to determine the effect of varying service life (10–40 years) on S1–S4; S4 shows equivalent to better environmental performance than S0. Carbonation was considered and result shows up to 8% of CO2 uptake can be achieved. In conclusion, S4 depicts solutions and concepts that result in environmental improvement potentials for a LHNB from geopolymer composites. The results from this study supported decision-making and guided in the development a 20 m LHNB from 83% industrial side-streams and 0.3% alkali activator maintaining a 10 dB absorption capacity.