脂肪族离子固化剂改性水泥土的机理研究

水泥基材料加固土(水泥土)存在早期强度低、易开裂变形等性能缺陷。为对其改性,在水泥土中掺入含水率体积1/300~1/50不等的新型土壤固化材料,离子固化剂(ISS)。通过无侧限抗压强度试验、体积化学减缩试验,探究了ISS改性水泥土的可行性,并通过对表面吸附特性、物相构成演变、微结构特性的表征及分析,对ISS改性水泥土的机理进行了系统的研究。结果表明:ISS分子对于水泥土各组分具有显著的选择吸附性;ISS掺入水泥土后,能够提升体系内各组分的分散性并降低黏土矿物结合水的能力,进而加速土体内水化反应产物的生成,优化土体孔隙结构,提升土体强度并增大体积化学减缩;最优ISS掺量为1/150,过量的掺入会减弱ISS的改性效果,但可降低水泥土体积的化学减缩。相关成果可为离子固化剂应用于水泥土的改性提供一定的参照。

Mechanism of cemented soil modified by aliphatic ionic soil stabilizer

The relatively low early strength and significant cracks are the common issues for the cementitious materials-stabilized soil (cemented soil). To remedy its defects, novel ionic soil stabilizers (ISS) with dosages from 1/300 to 1/50 of water content volume of the cemented soil are applied. Through the tests on unconfined compressive strength and volume chemical shrinkage, the modification feasibility of ISS application is verified. Through the characterization and analyses of the surface adsorption behaviors, phase evolution and micro-structure, the modification mechanisms of ISS on cemented soil are systematically studied. The results indicate that the ISS molecules adsorb on the compositions of cemented soil selectively. After the ISS addition, the system dispersion is enhanced, the water combination capacity of soil minerals is reduced, thus accelerating the formation of hydration products, benefiting the pore distribution and increasing the volume chemical shrinkage. The optimum dosage of this study is 1/150, and the excessive addition will retard the modification effects but reduce the chemical shrinkage. The results can be used as a reference for the modification of cemented soil with ISS.