ABSTRACT
Hydrogen sulfide-induced corrosion threatens sewage concrete structures, requiring effective protection. This study evaluates the environmental impacts of seawater-derived magnesium hydroxide (Mg(OH)2) as a sustainable alternative to commercial Mg(OH)2 for concrete coatings. A cradle-to-gate life cycle assessment (LCA) analyzed coating ratios—100% seawater-derived, 75% SW - 25% CA, 50% SW - 50% CA, 25% SW - 75% CA, and 100% commercial—focusing on resource depletion, human health, and ecosystem impacts, following ISO 14040 and 14044 standards. Results show seawater-derived Mg(OH)2 has lower environmental impacts, particularly in resource depletion and climate change potential. For a DPWH drainage project in Manila (13,875.84 m²), using pure seawater-derived coatings reduced environmental impacts by 3,092,680 mPt—equivalent to the annual emissions of 2.8 cars or 8.5 households. These findings underscore seawater-derived Mg(OH)2 as an eco-friendly, sustainable alternative for concrete protection in the construction industry.
