New approach for the measurement of gas permeability and porosity accessible to gas in vacuum and under pressure

Abstract

This study proposes new approaches for measuring the gas permeability and the accessible porosity of porous media. Two techniques are used: the usual permeameter, of the Cembureau type (measurement under pressure), and a new technique named a "double-cell" permeameter, based on a vacuum technique. Theoretical and experimental results point out that the apparent permeability measured in vacuum is proportional to the permeability measured under pressure. For a given pressure, the theoretical expression of the coefficients of proportionality leads to a quasi-constant value for a very large range of concrete permeability. A new equation is also proposed to evaluate the accessible porosity from the Time to Reach Steady State (TRSS) recorded during permeability tests. Concordance between the porosity accessible to gas obtained in this way and the porosity measured by the usual technique of hydrostatic weighing is discussed.

Dimensional accuracy of acrylonitrile butadiene styrene and polylactic acid samples printed in vacuum-assisted material extrusion system

“…Depending on vacuum intensity, heat retention can extend. Diminished air molecules within a chamber minimize thermal energy transfer through convection [32,33]. Consequently, applying a vacuum with varying strength can reduce heat loss and maintain it over an extended duration [34,35].…”

Study of Attapulgite as an Additive in Reinforced Concrete by Substitution of Cement and Its Effects on the Durability Properties of Hardened Concrete

“…The samples are then dried in an oven at 105˚C until the mass is stabilized to obtain the dry mass (M dry ). The mass is considered constant when the difference between the values obtained after two successive weighings (24 h interval) is less than 0.05% (Reference [14]). The porosity accessible to water is calculated according to Equation (1):…”

Two-Dimensional Microstructure-Based Model for Evaluating the Permeability Coefficient of Heterogeneous Construction Materials

“…Alternative methods, such as the mercury injection method and water saturation method, are also utilized to evaluate concrete permeability in the existing literature [17]. In addition to the abovementioned methods, researchers have devised test methods to measure the apparent gas permeability of cracked concrete [18] and the permeability of porous media using vacuum technology [19]. These additional methods expand the range of techniques available for assessing concrete permeability.…”