Contribution of Bio-Based Buildings Made with Seaweed and Seagrass in the Construction Industry. A Bibliographic review

Due to the construction industry, the climate crisis had deepest environmental impact. In addition to consuming scarce mineral-based materials, the building industry is responsible for up to 39% of global carbon dioxide emissions and the accumulation of solid waste in landfills, rivers, and seas. To cut carbon dioxide emissions and mitigate the effects of climate change on the construction industry, a new, more sustainable, and renewable production matrix must be considered. An approach is using seaweed and seagrass as bio-based materials matrix, from macroalgae or microalgae stranded on the shore or sustainable crops. Transforming algae into usable construction materials involves a process of harvesting, processing, and refining. This article has systematically reviewed the literature about advances and the potential of using marine species as construction materials matrix. To this end, this paper explores the existing literature on architectural projects and research on various species of seagrass and seaweed worldwide. This review concludes that numerous case studies of dwellings around the world have demonstrated and validated the use of seaweed for applications such as coatings, thermal insulation, and construction additives. Among the most important construction related properties of seaweed are fire resistance, low thermal conductivity, and resistance to moisture and insect damage. For instance, prototypes incorporating Neptune grass (Posidonia oceanica) exhibited a thermal conductivity of 0.044 W/m·K comparable to that of expanded polystyrene, which typically ranges between 0.035 and 0.037 W/m·K. The availability of seaweed, considered the waste that pollutes an essential part of the world's coastline, is increasing every year. Nevertheless, not all types of seaweed can be used as construction materials. For this reason, there are some challenges in creating sustainable cultivation of seaweed species, like the need for efficient methods, harvesting, and its processing. In consequence, these costs must be incorporated into the selling price. However, these difficulties do not diminish the seaweed and seagrass's potential as a renewable substitute in the production matrix of the construction industry. These challenges must be overcome before the industrial use of marine species as building materials becomes a reality. Governments must provide financial support to get these initiatives off the ground, especially in the crucial pre-competitive phases. At the same time, the development of prefabrication systems is of vital importance. These systems will enable certification and compliance with building materials regulations and pave the way for a more sustainable future for the industry. It is also necessary to establish seaweed and seagrass cultivation methods that will make the initiative sustainable in the long term, incorporating the costs associated with cultivation, harvesting, and processing into the selling price.