Development of techniques on concrete pore structure and distribution observation

众所周知，混凝土的大部分性能都受其孔结构的影响。特别是，混凝土的渗透性取决于其孔结构。因此，准确测量混凝土的孔结构对了解混凝土的耐久性是有益的。我们已经开发了一种通过镓渗透和EPMA观察来了解硬化水泥浆体中孔结构的技术。在本研究中，我们研究了一种利用镓检测混凝土硬化过程中孔结构的方法，得到了以下结论：1.用冻结法将混凝土硬化过程中的水分状况清除为三层。2.研究表明，混凝土中水分的运移受到水胶比的影响。通过EPMA对气孔内的Ga进行定位，可以观察到气孔的形状。在本研究中，利用EPMA获取的图像，用随机游动的方法估计扩散系数，即多个颗粒在混凝土孔结构中随机行走。5.用扩散池法测量氯化钠溶液的渗透率。讨论了用掺镓方法测定氯化钠溶液渗透率与孔结构的关系。因此，孔隙连通性与渗透率密切相关。

It is well known that most of property of concrete is influenced by its pore structure of concrete. In particularly permeability of concrete is dependent on its pore structure. Therefore, it is beneficial to know durability of concrete that pore structure is measured exactly.We already developed the technique to make clear the pore structure in hardened cement paste by gallium intrusion and the EPMA observation.In this study, a method of examining the pore structures during hardening concrete was investigated by using Ga, and the following conclusions were reached.1.The water condition during the hardening concrete was cleared to divide three layers by using the frozen method.2.It was shown that a concrete amount of the moisture movement was influenced by W/C, and the change of it was large during green concrete.3.By mapping of Ga fixed in the pores using an EPMA, it was possible to observe the shapes of pores. This had conventionally been unavailable by other methods, including mercury intrusion porosimetry.4.In this research, using a image acquired by EPMA estimates diffusion coefficient with random walk which is many particles was walking in concrete pore structure with random.5.The permeability of NaCl solution is measured by method of diffusion cell. Relationship between permeability of NaCl solution and pore structure by measuring gallium intruded method is discussed. As a result, pore connectivity and permeability is closely relationship.