高水速凝材料-软土微观结构的SEM研究

高水速凝材料是一种新型的固体混合材料，它与普通硅酸盐水泥相比有许多独特的特点：(1) 水用量大；(2) 速凝早强；(3) 可泵时间长；(4) 良好的塑性特性；(5) 极限荷载后强度具再发展性能。虽然，高水速凝材料在煤炭和冶金系统得到了较广泛的应用，取得了较好的技术经济效益，然而，在其它领域还未曾应用过。为了探索高水速凝材料在软土地基方面的应用前景，笔者采用扫描电镜研究了高水速凝材料-软土凝固体的微观结构。研究结果表明，纯土的土颗粒之间只有原生矿物的几何堆积，而没有牢固的连接。但由于高水速凝材料的加入，彻底改变了土体结构。在高水速凝材料-软土凝固体中，主体结构为钙矾石结晶体形成的“空间网状结构”；辅助结构为在碱性环境中土颗粒之间的离子交换、团粒化作用和碳酸化作用所形成的微晶体与凝胶体结构。因此，高水速凝材料在地基处理方面具有较好的应用前景。

SEM study of microstructure of soft soil mixed with high-water-content and quick-setting materials

The high-water-content and quick-setting materials are a new kind of cement with many unique properties: 1. high water content; 2. quick setting and strengthening; 3. long pumpability time; 4. good plasticity; 5. the property of re-developing strength after ultimate loading. Although having been widely used in coal and metallurgy systems with remarkable technological and economical benefits, the materials have not yet been applied to geotechnical engineering. In order to explore the foreground of applying the materials to the soft soil foundation, the study on the microstructure of the soft soil with the materials is conducted by SEM. The results show that there only exists the geometrical drift of sedentary minerals without firm connection among the pure soil particles. However, the soil structure completely changed with materials added to it. In the consolidated soft soil-materials, the principal structure is the “spatial cellular structure” of calcium crystal. The supplementary structure is the micro-crystal and gel structure which is formed among the soil particles in alkaline environment through ion exchange, aggregation and carbonation. Thus, the materials may have a good foreground of application to ground treatment.