Review of availability of source materials for geopolymer/sustainable concrete

Previous research has not sufficiently addressed the availability of geopolymer concrete raw materials, which influences adoption for infrastructure constructions. The overview herein assesses the supply, demand, and cost of these raw materials, including fly ash, slag cement, metakaolin, sodium hydroxide, sodium silicate, and silica fume. The results suggest that geopolymer concrete is a viable partial replacement for ordinary Portland cement (OPC) in the United States and Europe. Limitations exist in the rest of world, specifically China. Fly ash-based geopolymer concrete represents an opportunity due to low cost along with significant global production and reserves. Additionally, an activating solution composed of sodium hydroxide and silica fume with 25% Portland cement as a partial replacement appears to be most desirable. However, approximately only 7% replacement of OPC with geopolymer concrete is currently feasible globally due to limitations in sodium hydroxide supply. The analysis reveals a need for continued research to reduce the use of sodium hydroxide to improve availability and reduce cost of geopolymer concrete. (C) 2020 Elsevier Ltd. All rights reserved.