| 纳米硅溶胶固化黄土的黄土特性及其固化机理 |
| Alternative Title | Strength characteristics and modification theory of loess modified by Nano silica sol
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| 卜思敏 |
| Thesis Advisor | 吕擎峰
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| 2016-05-29
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| Degree Grantor | 兰州大学
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| Place of Conferral | 兰州
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| Degree Name | 硕士
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| Keyword | 黄土
纳米硅溶胶
强度
微观结构
固化机理
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| Abstract | 纳米硅溶胶是溶胶粒径为纳米级的胶体溶液，具有比表面积大、高分散度、高吸附性等优点，其广泛运用于纤维、纺织、橡胶、涂料、陶瓷等行业中，但将纳米硅溶胶用做土壤固化剂的研究较少。将新型纳米材料用作土壤固化剂能克服其它化学固化剂渗透性差、对环境有害等缺点。本文进行纳米硅溶胶溶液固化黄土的配比和机理研究，采用三种不同粒径的纳米硅溶胶进行黄土固化，对固化样进行液塑限试验、无侧限抗压强度试验、扫描电镜试验、X射线衍射试验和物理吸附试验，研究固化黄土的稠度特征、力学性质物相特征、化学组成和微观结构变化，分析纳米硅溶胶固化黄土的固化机理。
（1）三种不同粒径（10.7nm、29nm、100.1nm)的纳米硅溶胶固化土的无侧限抗压强度均有明显提高，且纳米硅掺量越高无侧限抗压强度越大。纳米硅溶胶固化样的早期强度较高，在养护条件相同的情况下，养护龄期对其影响不大。在相同掺量下粒径越小的硅溶胶固化样其无侧限抗压强度越大，固化效果最佳。
（2）随着纳米硅含量的增加，10.7nm和29nm纳米硅固化黄土的液塑限都增大，而100.1nm纳米硅固化黄土的液塑限都略有下降。纳米硅固化土的衍射谱图与压实黄土的基本匹配，纳米硅固化黄土的谱图出现了密集、低矮的非晶相物质峰群，没有新的晶体物质形成。纳米硅固化黄土以粒状架空和镶嵌接触结构为主，但颗粒表面被凝胶薄膜吸附或包裹，形态变为次圆棱状，颗粒边缘粗糙不清，接触面积变大。纳米硅含量相同时，随着纳米硅颗粒粒径的减小，比表面积和纳米级孔隙都增大；同一纳米硅粒径时，随着纳米硅含量的增加，比表面积和纳米级孔隙都增大，其中10.7nm和29nm粒径纳米硅固化黄土中形成了大量介孔孔隙。
（3）纳米硅溶胶固化黄土的作用主要为纳米颗粒的高表面能引起的细颗粒团聚填充作用和凝胶胶结作用，固化过程改善了固化土结构强度和孔隙分布，减少了大孔隙，提高了试样比表面积和介孔孔容。纳米硅粒径越小，细颗粒团聚填充效果越明显，尤其对于小于5μm的颗粒体的团聚作用显著。 |
| Other Abstract | Nano silica sol is a colloidal solution of colloidal silica particles in nanoscale, which has advantages such as big specific surface area, large dispersion and high adsorbability. It is widely used for fiber, textile, rubber, coating and ceramics industries. However, researches on nano silica sol as curing agent in soil are less. As soil stabilizer, the new nano material overcome the disadvantages such as low permeability and harm to environment as other chemical soil stabilizers do. In this paper, the ratio and mechanism of nano silica sol solution solidified loess is studied, and three kinds of nano silica sol with different particle sizes are utilized to solidify loess. In order to research Consistency characteristic, phase characteristics of mechanical properties, chemical composition and the changes of microstructure of solidified loess and to analyse the solidification theory, water content test, liquid and plastic limit test, unconfined compressive strength test, SEM, X-ray diffraction test, physical adsorption test and Fourier infrared spectrum test are carried out.
(1)Unconfined compressive strength of loess solidified by three different consistences nano silica sol all increases significantly, and the more the amount of admixture, the larger the amplification of strength. Early strength of solidified samples is comparatively high and length of curing period under same circumstance has little influence. Under the same dosage, the smaller the particle size of nano silica sol is, the greater the unconfined compressive strength and solidification effect of solidified samples will be.
(2)With the increasing of nano silica content,the liquid-plastic limit of loess solidified by nano silica in size 10nm and 29 nm were increased,but the liquid-plastic limit of loess solidified by nano silica in size 100nm was decreased. The X-RD patterns of loess solidified by nano silica and loess compacted were basically matched,there were appeared serried and low amorphous phase material peaks without new crystalline material. The main of nano silica solidified loess were granular overhead and inlaid contact structures,but it’s particle surface was adsorbed and parceled by gel films,the particle margin became rough and unclear,the contact area increase. When the content of nano silica were same,with the partical size of the nano silica particle decreased, the specific surface area and the size of nano level hole were increase;when the partical size of nano sili... |
| URL | 查看原文
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| Language | 中文
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| Document Type | 学位论文
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| Identifier | https://ir.lzu.edu.cn/handle/262010/226070
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| Collection | 土木工程与力学学院
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Recommended Citation
GB/T 7714 |
卜思敏. 纳米硅溶胶固化黄土的黄土特性及其固化机理[D]. 兰州. 兰州大学,2016.
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