Effects of coal-metakaolin on the properties of cemented sandy soil and its mechanisms

In this study, effects of coal-metakaolin (CMK) on mechanical and microstructural properties of cemented sandy soil were investigated. The mechanical properties were evaluated by unconfined compressive strength (UCS) and stress-strain relationships. By incorporating CMK, the 28 d UCS was improved by 1.68-2.18 times, the ultimate strain reduced to 1.63-1.75%. Microstructural properties were investigated by using thermogravimetry, X-ray diffraction, mercury intrusion porosimetry and scanning electronic microscopy. The results showed that CMK can accelerate cement hydration, refine pore structure, and improve the interfacial zone between soil particles and binder, due to its pozzolanic nature and fine particle size.