Minimising the global warming potential of clay based geopolymers

• A life cycle inventory (LCI) for Metakaolin is presented.
• A new methodology for geopolymer mix design is described.
• A reduction in Global Warming Potential of approximately 40% is achievable.
• The lowest Global Warming Potential can relate to the strongest mixes.

Production of Portland cement (PC) binders contributes substantially to global CO2 production and various bodies including the Intergovernmental Panel on Climate Change (IPCC) have identified geopolymers as alternative binders with the potential to reduce these emissions. The hypothesis of this research is to investigate whether this is a realistic proposition in the light of limited waste materials such as fly ash and ground granulated blast furnace slag commonly used as geopolymer precursors. The effect of use of natural clay minerals as alternative precursors on global warming potential (GWP) is investigated. Methods of designing mixes with the lowest possible GWP are presented and these are compared to the GWP of PC and currently available metakaolin based geopolymer binders. It is concluded that it is possible to reduce the GWP by approximately 40%, but other impacts may increase.