Abstract

An experimental investigation was conducted to understand the impact of salinity on the microstructure, phase composition, and shear strength of cement-treated Champlain Sea clay. Based on a scanning electronic microscopy (SEM) analysis, Champlain Sea clay exhibits an open structure fabric with flocculated particles. Leaching results in de-flocculation of the aggregates and leads to an increase in inter-aggregate porosity in the clay. Cement mixing transforms a dispersed microstructure into a flocculated state with a large amount of clay-binder aggregates. Cementitious products were formed and reduced both inter-aggregate porosity and intra-aggregate porosity in the cement-treated clay specimens. Sodium chloride salt has a negative effect on the strength development of cement-treated Champlain Sea clay. Under the same cement dosage of 50 kg/m³, the unconfined compressive strength of cement-treated leached clay samples exhibited higher shear strength values than those at natural or a higher salinity level. An optimum salinity level was found to be at 1.33 g/L in this study to achieve the highest shear strength, which was confirmed with the densest microstructure in the SEM and a series of stronger and wider cementitious peaks of cementitious products in the X-ray diffraction analysis.

摘要

进行了一项实验研究，以了解盐度对水泥处理的尚普兰海粘土的微观结构、相组成和剪切强度的影响。根据扫描电子显微镜 (SEM) 分析，尚普兰海粘土呈现出具有絮凝颗粒的开放结构织物。浸出导致聚集体去絮凝并导致粘土中聚集体间孔隙率的增加。水泥混合将分散的微观结构转变为絮凝状态，其中含有大量粘土粘合剂聚集体。水泥制品的形成并降低了水泥处理粘土试样中的骨料间孔隙率和骨料内孔隙率。氯化钠盐对水泥处理的尚普兰海粘土的强度发展有负面影响。相同水泥用量50 kg/m下^{如图3所示}，水泥处理的浸出粘土样品的无侧限抗压强度显示出比天然或更高盐度水平的那些更高的剪切强度值。在本研究中发现最佳盐度水平为 1.33 g/L 以实现最高剪切强度，这通过 SEM 中最致密的微观结构和 X 射线中胶凝制品的一系列更强和更宽的胶凝峰得到证实衍射分析。