Environmental Assessment of Alkali-Activated Mortars Using Different Activators

Abstract

This study sheds light on the environmental performance of three alkali-activated mortars (AAMs) using sodium hydroxide, sodium silicate powder and 2-part aqueous alkali solutions respectively, as activators. A comparative environmental assessment study of the different AAM mix-designs and Ordinary Portland Cement (OPC) mortar was carried out using Life cycle assessment (LCA) methodology. Results showed a significant difference in the environmental performance of the different AAMs. The mix-designs activated using sodium hydroxide and 2-part aqueous alkali solution respectively, were more environmentally sustainable than OPC. Based on the contribution analysis conducted, the alkali-activators were the significant contributors especially sodium silicate powder activator, which is produced consuming thrice the amount of energy needed to produce sodium silicate aqueous solution. This study indicates that depending on the type and quantity of activators, AAMs can be more or less environmentally sustainable than OPC mortar. Hence, development of AAMs with lower amounts of alkali activators without compromising on their mechanical properties shows great potential in reducing their environmental burdens