Geopolymer Concrete at Ambient and Elevated Temperatures: Recent Developments and Challenges

Abstract

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.

Mix Design Processing for Self Compacting Geopolymer Mortar

“…The influencing parameters which affect the fresh mechanical properties of GPC were determined as water to geopolymer solid ratio (W/GPS) and alkaline activator to binder ratio (Hardjito and Rangan 2005;Aliabdo et al 2016;Elyamany et al 2018). Tao and Pan (2019) concluded that the research efforts to make a flowable GPC are very scarce and the innovation of a superplasticizer for making cost effective GPC is also mandatory for practical application. In addition, self-compacting geopolymer concrete (SCGC) is a revolutionary concept in the construction industry to keep the people away from the compaction work on the material including highly concentrated alkaline liquid.…”

Solidification of (Pb–Zn) mine tailings by fly ash-based geopolymer I: influence of alkali reagents ratio and curing condition on compressive strength

“…This result is in agreement with Provis, and van Deventer's [37,38] findings, which confirmed that the mechanism of geopolymerization could be strongly encouraged if the binder is treated at a temperature between 60 and 90 °C for 8-24 h. In addition, many researchers have already experienced a similar influence from curing temperatures, such as Bakria et al [29,38]. Therefore, curing at too extreme temperatures or for a significantly prolonged period may undermine the microstructure and cause increased shrinkage and fracturing, resulting in reduced strength [16,39].…”

Up-scaling of fly ash-based geopolymer concrete to investigate the binary effect of locally available metakaolin with fly ash

“…It was also observed that heat cured specimens resulted in more compressive strength than ambient cured specimens as polycondensation of geopolymer increases at elevated temperature due to complete dissolution of Al and Si, hence resulting in more hydrates products at early ages of curing and reduced the initial setting time [ 27 , 42 , 43 ]. As a matter of fact, it was also observed that the difference between compressive strengths were more at earlier ages as compared to later age of mixes [ 9 , [44] , [45] , [46] ]. Comparison of average compressive strengths of fly ash based GPC at various ages is presented in Fig.…”