摘要
以河南安阳弱膨胀土为对象,通过"水汽等温吸附–热失重、差热分析"对膨胀土表面吸附结合水类型进行界定,比较分析离子土固化剂(ISS)改性前后,膨胀土结合水分布形态及数量变化,并基于傅里叶红外光谱,从水分子结构振动信息角度对膨胀土吸附结合水类型界定方法进行定性验证;结合ISS改性前后黏土矿物组分、表面理化性质的变化,解释分析了不同水汽湿度区间内,ISS对膨胀土水合行为的作用模型及改性机理。结果表明:达到一定的水汽"特征"湿度段,土表面水合状态和结合水性质将发生转变,根据热曲线的脱失温度区间可将结合水界定划分为三种类型:强结合水,"过渡"结合水和弱结合水。ISS作用后,土吸附强结合水量无明显改变,"过渡"结合水及弱结合水含量显著降低。ISS通过对膨胀性黏土矿物表面及层间的物化作用,弱化黏土矿物部分"水合活性中心"能量,从而抑制了膨胀土水化膨胀势。
The ＂water vapor adsorption isotherm - TG, DSC＂ method is proposed to define and investigate the type of bound water of typical Anyang weak expansive soils. A comparative analysis of the distribution characteristics and amount of bound water is made between the original soil and ISS-soil. From the perspective of water molecular structure vibration and based on the theory of Fourier transform infrared spectroscopy, the rationality of the proposed method is also qualitatively validated. Finally, the effect of ISS on the bound water is interpreted in terms of the change of the clay mineral composition and surface physicochemical property. The test results indicate that the distribution state and property of the boundwaer will alter at specific relative humidity interval. According to the TG - DSC curve, the bound water can be divided into three types at different elevated temperature ranges, i.e., strongly bound water, transitional bound water and weakly bound water. After modification, the strongly bound water remains consistent while the transitional and weakly bound water significantly decreases. The ISS weakens the capacity and ability of hydration of outer surface and interlayer of expansive clay mineral and hence effectively inhibits the swelling potential induced by the soil hydration.
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2012年第10期1887-1895,共9页
Chinese Journal of Geotechnical Engineering
基金
国家自然科学基金项目(41202199
41272308
40972185)
中央高校基本科研业务费专项资金资助项目(CUG110825)
教育部高等学校博士学科专项科研基金项目(200804910504)
关键词
离子固化剂
膨胀土
水汽吸附
结合水
黏土矿物
ionic soil stabilizer
expansive soil
water vapor adsorption
bound water
clay mineral
