Permeability Comparison of MgO-carboanted Soils and Cement-Treated Soils
Carbonation of reactive magnesia (MgO) is employed for treating soft soils, which has received attention in the ground improvement as an innovative technology. However, no literature on the permeability of reactive MgO-carbonated soils has been studied. Based on the previous research, this paper focuses on the permeability coefficient of reactive MgO-carbonated soils and PC-treated soils. Through the laboratory permeability tests, the influence of reactive MgO content, carbonation time, initial water content and CO2 ventilation pressure on the permeability coefficient of carbonated silt and silty clay was systematically studied. Moreover, the permeability coefficient of PC-treated soils was used for comparison under the same conditions of MgO content and initial water content. The results show that: the permeability coefficient of reactive MgO-carbonated soils reduces with the MgO content increasing, it is the same magnitude with that of PC-treated soils at the same dosage; and the permeability coefficient of carbonated silt is obviously larger than that of carbonated silty clay. When both the MgO-stabilized silt and silty clay are carbonated for 6.0 h, the corresponding permeability coefficient could reach the minimum (10−6 m/s). Ventilation pressure has little effect on the permeability coefficient of reactive MgO-carbonated soils, which is slightly smaller when the ventilation pressure is 200 kPa. Therefore, the reactive MgO-carbonated soils have similar impermeability with PC-treated soils, and have a good prospect of popularization and application.
KeywordsMagnesia Carbonation Cement Silt Silty clay Permeability
The authors appreciate the financial support of NSFC (41330641, 51279032), National key research and development projects (2016YFC0800201).
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