Life Cycle Assessment of Lightweight Ceramic Clay Aggregates Sintered in a Microwave Oven with the Incorporation of Sargassum spp . Particles

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Sargassum spp. is a brown seaweed originally found in the Sargasso Sea, in the tropical Atlantic region and Gulf of Mexico. Its increase in recent years and its movement toward the coastline has become a serious problem for countries along the tropical Atlantic, including Brazil. The accumulation of these seaweeds on beaches can bring harmful effects to human health due to emissions from its decomposition such as ammonia, hydrogen sulfide, and methane. It also impacts tourism, fishing, and the regional marine ecosystem. Seaweeds are often collected and discarded in landfills without any practical use. This study aims to evaluate the addition of Sargassum particles in ceramic clays in order to develop alternative and sustainable lightweight aggregates. Several characterizations of the raw material were carried out before its use. For use in lightweight ceramic clay aggregates, sargassum was incorporated into samples at proportions of 0%, 20%, and 40%. Samples were shaped by extrusion and sintered at temperatures of 800°C, 900°C, and 1,000°C in conventional and microwave ovens. Linear shrinkage, water absorption, apparent porosity, apparent density, and compressive strength tests were carried out. A comparative life cycle assessment (LCA) was carried out between expanded clay and the different formulations of aggregates. Our results indicate that the addition of sargassum led to a reduction in apparent density of the lightweight ceramic clay aggregates, especially at 40%. Nevertheless, only the materials sintered through microwave oven met the strength requirements for all temperatures. This is attributed to densification and refinement in the structure. The LCA suggests better environmental performance for materials with sargassum compared to expanded clay—a commercially available aggregate. Lightweight ceramic clay aggregates with sargassum sintered in a microwave oven prove to be a viable alternative, offering mitigation from sargassum inundation events, a reduced consumption of finite natural resources, and enhanced energy efficiency.

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