Exploring soil geopolymer technology in soft ground improvement: a brief excursion

Abstract

Due to environmental concerns of global warming, a new generation of aluminosilicate binders called geopolymers has gained attention in recent years to replace cement and other calcium-based materials. The trend in the development/application of soil geopolymers was discussed in the present study for better performance and wide adoption in soft ground improvement. The current and future trends in the analyses of micro-level changes in connection with the macro properties of soil geopolymers were presented initially. The factors that affect soil geopolymer development were then discussed including curing conditions, type of liquid alkali activator, a ratio of hydroxide to silicate alkali, the concentration of the alkali hydroxide, the water content in the mixture, preparation method/mixing time, precursor and ratio of alkali activator to precursor content. These factors were separated into those with ascertained effects and those with inconclusive outcomes, needing further research. In addition, the existing areas of application of soil geopolymers were presented, and the potential areas of application were pointed out, based on the requisite properties of soil geopolymers for various ground improvement applications. The soil geopolymer properties, which require more in-depth study, were identified. Regulatory and optimisation issues associated with the development/application of soil geopolymers were elucidated, including the presentation of preliminary experimental results, to further consolidate the discussion. The potential effect of the interaction of factors in studying soil geopolymer development was revealed, as a means to address anti-synergistic effects that may result. The upshots of the study were assessed to provide useful insights for future development/application of soil geopolymers in soft ground improvement.