【目的】研究CaO改性赤泥固化黄土的电阻率特性。【方法】对不同CaO和赤泥掺量以及养护龄期条件下的电阻率进行测试,分析了电阻率的变化趋势。另外,测试了不同条件下试样的XRD、SEM、EDS和孔隙度、孔喉分布率,通过分析微观指标的差异揭示了电阻率的变化机理。【结果】研究结果表明:随着CaO和赤泥的增加,电阻率呈现降低的趋势;与水泥固化土相比,CaO改性赤泥固化土孔隙水中的导电离子在离子种类和离子浓度两方面都有所增加,这导致孔隙水的导电性增加;而CaO改性赤泥固化土的孔隙度和孔喉分布率差别不大,所以试块内部的导电通路差别不大。随着养护龄期的增加,电阻率整体呈现出对数增长的趋势;水泥固化土中的导电离子因参与反应逐渐减少;CaO改性赤泥固化土中过量的CaO未参与反应,导致孔隙水中的导电离子持续存在,因此养护龄期大于28d时孔隙水的导电性降低幅度有限;另外,由于固化土的孔隙度和孔喉分布率均有所增加,且试块处于非饱和状态,故其内部断路增多导致导电通路减少,致使电阻率随着龄期的增加而变大。

【Purposes】This study focues on the resistivity characteristics and mechanism of solidified loess mixed with CaO-modified red mud.【Methods】 The resistivity of the samples with different CaO and red mud contents and curing ages was tested.  In addition, XRD, SEM, EDS, porosity, and pore-throat distribution of these samples under different conditions were tested to analyze the mechanism of re-sistivity change.  【Findings】 The results show that the resistivity decreases with the increase of CaO and red mud contents.  Compared With respect to cement solidified soil, the types and concentrations of con-ductive ions increase in pore water of the cement solidified soil modified by CaO and red mud, which leads to the increase of conductivity of pore water.  With the increase of curing age, the resistivity overall pres-ents a trend of logarithmic increase.  because of the excessive CaO unreacted in the solidified soil, the conductive ions still exist in pore water.  Therefore, the decrease of pore water conductivity is limited when the curing age is longer than 28 days.  Moreover, owing to the increase of the porosity and pore-throat dis-tribution of the cement solidified soil modified by CaO and red mud, the internal disconnecting paths in-crease and the conduction paths reduce, which increases the resistivity with the increase of curing age.