A Comparative LCA study on the refurbishment of quays with induced mineral deposition technology

Abstract: A quay is a structure which is constructed along the shoreline for docking purposes. When the quay is constructed using reinforced concrete, damage over time happens under the combined action of chemical and mechanical corrosion of the varied materials. The quay columns situated in the seawater are commonly corroded due to the chloride ingress and frost attack. These deteriorations significantly reduce the service life of the quay column. Reinforced concrete materials are traditionally used to repair the eroded quay structures in the present circumstances but have significant environmental impacts. As a sustainable alternative, a calcareous electrochemical precipitation, induced mineral deposition (IMD) after sea water electrolysis, has been suggested for refurbishing underwater structures. This thesis aims to evaluate the carbon footprint associated with the IMD approach from a life cycle perspective. The critical hotspots and the trade-offs of this approach are identified and compared with the concrete-based refurbishment. It is found that the primary contributors to the carbon emissions are the upstream processes involving the production of IMD materials. Similarly, a significant amount of carbon emissions occurs from the use of electricity in the downstream processes. However, IMD approach outperforms the concrete refurbishment on an overall climate change impact. The results from the sensitivity analysis also demonstrate that use of less carbon- intensive anode materials and the complete transition of grid electricity in the use phase into renewable energy resources would environmentally benefit the IMD approach. Therefore, for the refurbishment of marine quay columns, the IMD approach with asserted recommendations would be a sustainable alternative to the current practices.