Comparative Life Cycle Assessment of Conventional, Glass Powder, and Alkali-Activated Slag Concrete and Mortar

This study compares the cradle-to-gate greenhouse gas emissions (GHGs), energy use, water use, and potential environmental toxicity of conventional (Conv), glass powder (GP), and alkali-activated slag (AAS) concrete and mortar. The comparison is based on 1 m(3) of concrete/mortar with similar 28-day compressive strength, so the same concrete/mortar member with same dimensions may be manufactured from Conv, GP, or AAS materials and used for same applications. The result shows that compared to a 35-MPa Conv concrete, a 35-MPa GP concrete has, on average, 19% lower GHGs, 17% less energy, 14% less water, and 14-21% lower environmental toxicity. A 35-MPa AAS concrete has 73% lower GHGs, 43% less energy, 25% less water, and 22-94% lower effects for all environmental toxicity categories except an 72% higher ecotoxicity effect. Environmental impact reductions are also found for using GP as a cement replacement in concrete with lower strengths and replacing cement with GP or AAS in mortars with different strengths. The paper concludes that using alternative cementitious materials GP and AAS as cement replacements could significantly reduce the environmental impacts of cement-based products. (C) 2014 American Society of Civil Engineers.