水泥基材料气体渗透性研究进展

发布时间：2018-02-11 06:12

本文关键词： 水泥基材料气体渗透性试验装置孔隙结构饱水度　出处：《硅酸盐学报》2015年10期 　论文类型：期刊论文

【摘要】：综述了水泥基材料气体渗透机理、渗透性测试原理与方法以及气体渗透性的预测模型。气体在水泥基孔隙材料中的渗流过程包括粘性流动、边界滑流以及Knudsen扩散。水泥基材料的透气性测试分为常压流量法、变压流量法以及变压压力法。水泥基材料通过物理孔隙结构和孔隙含水率影响气体渗透性。现有文献表明:气体渗流规律缺少关于对纳米尺度上Knudsen扩散对整体渗流总体贡献的定量研究,使气体渗透性与材料微观结构的模型的适用性受到影响;常压流量法物理原理明确,是实验室测量气体渗透性的标准方法,其他方法需要与之比对来确定其有效性;水泥基材料孔隙结构影响气体渗透性的关键参数是孔隙率和渗流特征尺寸,相关模型对水泥净浆适用性较好,但对砂浆和混凝土较差;水泥基材料孔隙含水率与气体渗透性的关系可通过Van-Genuchten-Mualem模型来表达,但模型参数离散性较大。
[Abstract]:The gas permeation mechanism, permeability testing principles and methods, and the prediction model of gas permeability in cement-based materials are reviewed. The seepage process of gas in cement-based porous materials includes viscous flow. Boundary slip flow and Knudsen diffusion. The permeability test of cement-based materials is divided into atmospheric pressure flow method, Variable-pressure flow method and variable-pressure pressure method. Cement-based materials influence gas permeability through physical pore structure and pore moisture content. The current literature shows that the law of gas percolation is not relevant to the overall permeability of Knudsen diffusion on nanometer scale. A quantitative study of the overall contribution of flow, The applicability of the model of gas permeability and material microstructure is affected, the physical principle of atmospheric pressure flow method is clear, it is the standard method to measure gas permeability in laboratory, and other methods need to be compared to determine its validity. The key parameters affecting gas permeability of cement-based materials are porosity and percolation characteristic size. The correlation model is suitable for cement paste, but it is not good for mortar and concrete. The relationship between pore water content and gas permeability of cement-based materials can be expressed by Van-Genuchten-Mualem model, but the model parameters are discrete.
【作者单位】：教育部土木工程安全与耐久重点实验室清华大学土木工程系;
【基金】：国家自然科学基金(51378295)资助项目
【分类号】：TU528

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