Sustainability assessment of half-sandwich panels based on alkali-activated ceramic/slag wastes cement versus conventional building solutions

Abstract

This study assessed the sustainability of two partition walls and intended to contribute to the Circular Economy in the construction sector. A life cycle approach and a multi-criteria decision support method were applied to know the environmental, functional, and economic performances of the production process of half-sandwich panels based on alkali-activated ceramic/slag waste cement, choosing as system boundary the method “cradle to gate”. The proposed building solutions differ from each other in the type of insulating material used, either extruded polystyrene foam (APXPS) or expanded cork agglomerate board (APICB). Besides, a comparative analysis of the developed building solutions versus three reference constructive solutions: i) a conventional heavyweight partition wall, ii) a lightweight gypsum wall panel, and iii) a conceptual lightweight sandwich membrane building solution was performed. Results showed that the two proposed half-sandwich wall panels (APXPS and APICB) resulted in the most sustainable alternatives, of which the APXPS obtained the best overall results since it combined the best environmental, functional, and economic behavior. Besides, the environmental contribution analysis determined that the greatest environmental burden to the Global Warming Potential (GWP), in the case of the APXPS was associated with the XPS (57%), being the alkali activator (23%) placed as the second major contributor. When the ICB was used as the insulation layer, the energy used (nearly 38%) and the sodium silicate (about 17%) were the larger contributors to CO2 emissions. It is worth mentioning that the use of ICB represented a negative contribution (of about −34%) to the GWP category.