Alginate in Architecture: An Experimental Approach to the New Sustainable Building Material

The embodied carbon emissions from building materials and construction are today responsible for 38% of annual global GHG emissions in the current global environment. If we are to reach the European energy plan with net-zero emissions by 2050, now is the time to rethink our construction principles, as well as building elements and materials. One of the possible steps to achieve this goal is to explore new solutions using regional sources and sustainable raw materials. In our research, we use alginate to see if we can substitute conventional structural elements with others based on this sustainable material, whose potential in architecture is so far unrevealed. Alginate, which is found in brown algae cell walls, is an irreversibly hardening elastic moldable material, i.e. once hardened, its form can neither be changed nor converted back into an original state. In this paper, we present a series of experiments with different natural additives. By respecting the natural behaviour tendencies of macroalgae, but also by experimenting with chitosan to increase the rigidity and glycerin to increase the elasticity of the alginate, various shapes of elements are obtained, ranging from linear ones, towards membranes and shells. An initial tensile test is made for the linear elements and the results are commented in comparison to similar natural fibres. The created models demonstrate promising outcomes while also opening some new research questions, confirming the potential of this innovative application.