Geopolymer concrete at ambient and elevated temperatures : recent developments and challenges

Geopolymer concrete (GPC) is attracting increasing attention due to its potential to replace ordinary Portland cement (OPC) concrete to reduce the carbon dioxide emissions from cement production. Although extensive research has been conducted in this area since the 1970s, its applications in engineering practice are still very limited. This paper briefly reviews the recent developments of GPC and its properties at ambient and elevated temperatures. It was found that GPC generally exhibits comparative properties to OPC concrete at ambient temperature. In contrast, GPC often has better fire performance and superior durability. Therefore, GPC could be advantageously used to improve the fire performance and durability of buildings and infrastructure. While a lot of aluminosilicate raw materials (such as fly ash) are low cost, the prohibitive costs of laboratory grade activators (such as sodium hydroxide and sodium silicate) greatly limit the widespread application of GPC. Therefore, there is a need to develop low-cost geopolymer concrete. Meanwhile, a few other challenges should also be overcome, such as difficulties to achieve consistent properties and to control efflorescence of GPC. Further research is required at both material and structural levels to address these issues. Particularly, there is a need to develop relevant building codes to promote the use of GPC in practice.