Villani Chiara, Snyder Kenneth A, Weiss W Jason
Adv Civ Eng Mater. 2015;4(1). doi: 10.1520/ACEM20150021.
This paper explores a new approach to estimating the pressure-dependent gas permeability of a cementitious material when using a falling-head gas permeameter. A series of experiments were performed on mortars with varying mixture proportions, and measurements were made with different initial applied pressures. The governing equation is based on an analogy to a falling-head liquid permeameter, but accounting for the gas compressibility and the pressure-dependent Klinkenberg effect that can occur during gas permeation. This formulation overcomes a limitation of other approaches that depend on the initial pressure that is applied and on the range of data that can be considered when evaluating transport properties. Analyses of the experimental data confirm that the apparent permeability is inversely proportional to the pressure applied as per the Klinkenberg equation. By accounting for this effect, it is possible to determine an intrinsic permeability that is independent on the pressure, and is a true characteristic of the pore space available for gas transport.
本文探讨了一种在使用落头式气体渗透仪时估算胶凝材料压力相关气体渗透率的新方法。对不同配合比的砂浆进行了一系列实验，并在不同的初始施加压力下进行了测量。控制方程基于与落头式液体渗透仪的类比，但考虑了气体可压缩性以及气体渗透过程中可能出现的压力相关克林肯伯格效应。该公式克服了其他方法的局限性，这些方法依赖于所施加的初始压力以及评估传输特性时可考虑的数据范围。对实验数据的分析证实，根据克林肯伯格方程，表观渗透率与施加的压力成反比。通过考虑这种效应，可以确定一个与压力无关的固有渗透率，它是可用于气体传输的孔隙空间的真实特征。
