摘要：The potential of using a new composite curing agent that consists of a mixture of cement,fly ash and desulfurization gypsum (CFG) for solidification of expansive soils was evaluated in this study.The unconfined compressive strength (UCS) test was carried out to investigate the optimum ratio of the curing agent.And the permeability test was conducted to investigate the permeability characteristics of the solidified soils under the optimum ratio.In addition,the solidification mechanism of the ternary composite curing agent was analyzed by Scanning electron microscopy (SEM) test.The results demonstrate that the UCS of solidified soil increases with the increasing curing time,and the optimum ratio of the CFG is 4:3:1.Among them,cement contributes the most to the strength,followed by fly ash and desulfurization gypsum.Besides,the composite curing agent can effectively improve the impermeability of expansive soil; the permeability coefficient decreases with the increasing curing time,while it increases with the increasing osmotic pressure.Moreover,the SEM test shows that cement,fly ash and desulfurized gypsum promote each other during hydration.The alkaline environment formed by hydration of cement and the sulfate environment formed by gypsum can effectively activate the activity of fly ash to generate more gelatinous hydration products,thus enhancing the strength and impermeability of solidified soil.
