Environmental impact assessment of alkali-activated materials: Examining impacts of variability in constituent production processes and transportation

Abstract

This study compares the environmental impacts of blast furnace slag-, fly ash-, and metakaolin-based alkali-activated concretes with Portland cement (PC) concretes using life cycle assessment methodology. The variability in production processes of mix constituents across Europe and uncertainty associated with transportation distances are evaluated for both types of concrete. The recent data on soluble sodium silicates production was obtained from European manufacturers. Results show that alkali-activated materials have up to 57 % lower CO2 eq. emissions than PC concretes, while activators contribute between 13 % and 33 % to the total GWP of AA concrete mixes, depending on mix design. This paper concludes that taking into account variability in production technologies of precursors and activators, as well as of PC, alkali-activated materials still have lower CO2 eq. emissions than PC concretes.