Solidification and field assessment of soft soil stabilized by a waste-based binder using deep mixing method

In an effort to reduce energy consumption and protect environment, developing an alternative to reduce or replace the use of cement in soil stabilization has been a topic research since long. This paper presents a novel binder (called GS agent, G and S are the initials of gypsum and slag, respectively) for stabilizing soft soil based on industrial solid wastes. A series of laboratory tests and a field test adopting deep mixing method was conducted to compare and analyze the geotechnical properties of soft soils by the GS binder and cement. Scanning electron microscopy (SEM) was performed to reveal the micro-mechanism of the stabilized soft soils. The results showed that the stabilized soil had permeability approximately 1 order lower in magnitude than the untreated soil, and significantly increased the unconfined compressive strength and cohesion of the untreated soil. The novel agent produced more hydration products and its stabilized soil formed a relatively firm reticular structure as compared to the cement-stabilized soil. An empirical design method was developed for determining the mechanical properties of GS agent-stabilized soil. Its feasibility was verified through comparing the predictions with the test datum.