Daan Deckers, Yanshen Zhu, Erin Koos, Hans Janssen
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引用次数: 0
摘要
建筑围护结构的内部隔热是建筑物理学中的一个重要课题,因为这种技术有可能带来潮湿问题。为了解决这些问题,近年来流行使用憎水剂,这种憎水剂可以减少风吹雨淋的吸收量。当在建筑材料上使用这种憎水剂时,它会渗透到材料的孔隙网络中,从而附着在孔隙表面,使其具有憎水性。一般认为,由于药剂无法进入,一些较小的孔隙可以保持亲水性。然而,对这些亲水孔隙的深入微观研究还从未进行过。由于无法对聚合物链进行直接观察,本文使用 X 射线计算机断层扫描图像,在脱饱和过程的不同阶段对孔隙水平的水分储存情况进行成像,从而确定了使用 3 种不同憎水剂进行憎水处理的材料中亲水孔隙(部分)的位置。虽然在所研究的材料中没有发现完全亲水的孔体和孔喉,但在疏水孔体和孔喉的亲水角落仍有可能储水。与亲水介质相比,这些角岛的存在较少,而且不会形成连续的液体流动路径。因此,它们可以提供少量的水分存储位置,但不会对水分流动产生显著影响。
Microscopic Localisation of Hydrophilically Oriented Pore Bodies and Throats in Hydrophobised Porous Materials
Internal insulation of the building envelope is a prime topic in building physics, due to the risk of moisture problems that this technique entails. As a remedy to these problems, the application of a water-repellent agent, which reduces the amount of absorbed wind-driven rain, has become popular in recent years. When such an agent is applied on a building material, it penetrates the pore network of the material, hereby attaching itself to the pore surfaces and rendering them hydrophobic. It is generally believed that some smaller pores can remain hydrophilic due to the inability of the agent to enter. An in-depth microscopic investigation towards these hydrophilic pores, however, has never been performed. Since direct visualisation of the polymer chains was proven impossible, this paper locates the hydrophilic (parts of) pores in a material, hydrophobised with 3 different water-repellent agents, by imaging the moisture storage at pore level using X-ray computed tomography images at different stages of the desaturation process. While completely hydrophilic pore bodies and throats are not found in the studied material, water storage remains possible in hydrophilic corners of hydrophobised pore bodies and throats. These corner islands are less present than in hydrophilic media and do not form a continuous liquid flow path. Therefore, they provide possible locations for little moisture storage but do not contribute notably to moisture flow.
期刊介绍:
-Publishes original research on physical, chemical, and biological aspects of transport in porous media-
Papers on porous media research may originate in various areas of physics, chemistry, biology, natural or materials science, and engineering (chemical, civil, agricultural, petroleum, environmental, electrical, and mechanical engineering)-
Emphasizes theory, (numerical) modelling, laboratory work, and non-routine applications-
Publishes work of a fundamental nature, of interest to a wide readership, that provides novel insight into porous media processes-
Expanded in 2007 from 12 to 15 issues per year.
Transport in Porous Media publishes original research on physical and chemical aspects of transport phenomena in rigid and deformable porous media. These phenomena, occurring in single and multiphase flow in porous domains, can be governed by extensive quantities such as mass of a fluid phase, mass of component of a phase, momentum, or energy. Moreover, porous medium deformations can be induced by the transport phenomena, by chemical and electro-chemical activities such as swelling, or by external loading through forces and displacements. These porous media phenomena may be studied by researchers from various areas of physics, chemistry, biology, natural or materials science, and engineering (chemical, civil, agricultural, petroleum, environmental, electrical, and mechanical engineering).