Improving soft ground using lime or cement is commonly practiced in road engineering. However, these stabilization agents are high-carbon and energy-intensive. The current paper presents a study of using geopolymer (GP), a low carbon cementitious material, for soft ground improvement. The geotechnical properties of soft soil stabilized with different mixing ratios of GP were investigated, including plastic and liquid limits, undrained shear strength and unconfined compressive strength (UCS). The experimental results show that GP is effective in increasing the plastic and liquid limits, undrained shear strength and UCS of stabilized soil, whereas decreasing its plasticity index. Micro characterizations using XRD and SEM-EDS confirm that calcium aluminosilicate hydrate (CASH) is the major cementing material formed in the stabilized soil. The CASH gel fills the voids of stabilized soil and cements the soil particles together, leading to formation of a denser and stronger micro structure and hence improving mechanical properties of treated soil.

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