摘要
把纳米硅粉掺加到水泥土中,并对纳米硅水泥土进行无侧限抗压强度试验,借用地质学的矿物切片技术,对不同配合比下的纳米硅水泥土进行磨片,在显微镜下对薄片进行对比分析,并对部分试样进行了电镜扫描和X射线衍射分析。实验结果表明,纳米硅可以改善水泥土的宏观力学性能,对于增强水泥土而言存在一最佳掺量。小于这一个掺量随着纳米硅掺量的增加水泥土无侧限抗压强度增加,超过这一掺量反而会降低水泥土的强度。显微镜下纳米硅水泥土为嵌镶结构,白色相和黑色相部分嵌镶于微透明的红褐色的基质之中。石英、长石为粘性土中较为稳定的成分,显微镜下边缘清晰,无色透明。它一般不与纳米硅、水泥的水化产物,石英表面为水泥的水化产物和粘土矿物等所覆盖。水泥土中小于50 um的小孔隙随着纳米硅掺量的增加而增加,孔隙分布较均匀,而到了强度的最佳掺量后,小孔隙减小而大孔隙增加,从而降低了水泥土的强度,显微镜下对纳米硅水泥土孔隙及其分布特征的分析有助于对纳米硅增强水泥土的固化机理的研究。
Unconfined compressive strength of.nanometer silicon and cement-stabilized soils which is added by nanometer silicon powder is tested, and mineralogical microtomy of geology is applied to make discs so that comparative analysis of discs of various mix proportions of NCS observed under microscope can be studied. Analysis of Scanning Electron Microscope and X-ray Diffraction of practical samples are also investigated. Experimental results show that there has a proper nanometer content limits for compressive strength, and unconfined compressive strength will increase with increase of nanometer powder within the proper content. On contrary, the strength exhibits decrease with increase of nanometer powder surpassing the proper content. NCS has substructure which has reddish-brown matrix dotted with white phases and black phases. Quartz and feldspar, that have sharpen edges and water clear ,and that cannot react easily with hydrating products of cement and nanometer silicon, are stable sections of NCS. They are covered by hydrating products and clay minerals on the sUrface. Pores smaller than 50urn of equivalent diameter , which are distributed more uniformly, are increased with nanometer silicon content. Increasing large pores owing to surpassing optimum content of compressive strength may lead to decrease the strength of NCS. Analysis of pores and its distributions using microscope helps to do further studies of curing mechanism of NCS.
出处
《科技通报》
北大核心
2012年第9期31-35,66,共6页
Bulletin of Science and Technology
基金
国家自然科学基金资助项目(No.50979099)
关键词
纳米硅
水泥土
显微结构
孔隙
nanometer
cement-stabilized soil
microstructure
pore
