Seaweed boards as value-added natural waste product for insulation and building materials

Large amounts of seaweed are deposited on shores worldwide daily. The presence of this natural pollutant on the coast is not only considered an environmental burden but also often hinders the development of tourism in the affected areas. Depending on the beach surface area, local governments worldwide spend considerable portions of their budgets to remove seaweed from beaches. Moreover, the removed seaweed occupies increasing space in landfills where it is disposed. Seaweed is noncombustible and decomposes slowly over long periods. In this study, we consider the use of seaweed (a natural waste) as a value-added product for insulation and building materials. Seaweed (Posidonia Oceanica) boards with dimensions of 250 mm × 60 mm × 10 mm were obtained by pressing a mixture of processed seaweed and an organic binder. The as-prepared boards were analyzed for their physical–mechanical properties according to the British standards. The boards with a mean humidity level of 9.15% and density of 0.4045 g·cm⁻³ demonstrated a maximum bending resistance of 2.720 × 10³ N·m⁻² and mean expansion upon water adsorption of ∼10% with regards to length and width and ∼30% with regards to height. The tested samples showed significant humidity resistance according to the boiling test and an average thermal conductivity of 0.047 W·m⁻¹·K⁻¹, which is comparable to that of polystyrene. Computational analysis of the “seaweed material” model revealed significant thermal and mechanical properties. The mechanical strength of the computed material, including its high Young’s and shear moduli, renders it a promising candidate in construction.