The design of ternary all-solid-waste binder for solidified soil and the mechanical properties, mechanism and environmental benefits of CGF solidified soil

Utilization of industrial solid waste to develop binder and solidified waste soil, which can achieve ‘waste control by waste’. Based on the alkali-activated mechanism and interaction mechanism of the binder-soil particles-water, the component distribution ratio design method of ternary all-solid-waste binder for solidified soil was constructed. The CGF all-solid-waste alkali-activated binders (CGF binders) are composed of general industrial solid waste, with which calcium carbide slag (CCR) as alkali activator, ground granulated blast furnace slag (GGBS) and fly ash (FA) as high and low-activity pozzolanic material respectively. Macro and microscopic tests were performed to reveal the mechanical properties and solidification mechanism as well as quantitatively evaluate the environmental and economic benefits of CGF solidified pure clay, pure silt, and pure sand (CGF solidified soils). The results revealed that the strength of CGF solidified soils was significantly affected by the alkali activator content and the activity of pozzolanic materials, and the strength of partially CGF solidified soils were higher than cement solidified soils under the same conditions. The relationship between binder-soil particles-water, viz., the alkali-activated reaction between binder and water, along with the pozzolanic reaction between the alkali activator and the clay particles jointly determined the strength and strength growth rate of the solidified soil. The strength of the optimal CGF solidified soils were 1.38–2.30 times higher than cement solidified soils, however, the carbon emission per unit strength and cost per unit strength of the cement solidified soil were 71.43–125.02 times and 3.53–5.88 times higher than the optimal CGF solidified soils, respectively. The findings can provide a reference for the design and development of solid waste-based binders suitable for solidified soils.