Waste valorization for fabrication of geopolymers

Construction industry is one of the heaviest polluters due to high greenhouse gas emissions with approximately 11 % of global CO2 emissions, extensive use of virgin materials, and waste generation. Simultaneously, mining, metallurgy, energy, construction and demolition industries face a single common problem, which is constant generation of waste. Often these waste streams could find alternative applications and thus alleviate the ongoing problem of landfilling and waste management. There is one solution that would comprehend all these issues, and that is the fabrication of geopolymer composites. Geopolymers are construction materials based on alkali activation of aluminosilicate materials, matching or even surpassing the traditional cement-based materials in terms of strength and durability. This paper investigates the possible valorization of different industrial waste streams for geopolymer composite ingredients - precursor, activator, or aggregate. The investigation presents analyses of the most important material characteristics for the geopolymerization process, provided for 21 local waste streams from Norway, Poland, the Czech Republic, Romania, and Iceland. The physical and chemical properties of analyzed wastes imply that all materials could be favorable as a geopolymer ingredient.