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2019, MATEC Web of Conferences
Hygric properties can be estimated directly from pore structure information, represented by a network of regularly shaped pores, extracted from a pore structure image to conserve the real topology. On this network, pore-scale models of moisture behaviour determine the hygric properties of moisture storage and transport. The reliability of this approach is validated with a sintered-glass filter. Despite its more limited heterogeneity and pore size range relative to typical porous building materials, it provides a good basis for validating crucial pore-scale moisture processes. Measured storage data compare well to the estimated ad- and desorption moisture retention curves as well as to the saturated and capillary moisture content. Furthermore, the simulated whole-range moisture permeability curve agrees acceptably with measured data. The variation in modelling the pore space as a pore network model is also analysed by considering two distinct pore network extraction methods. The meas...
2016 •
MATEC Web of Conferences
Hygric properties of hydrophobized building materialsMoisture loads due to wind-driven rain can lead to accelerated decay of exposed building facades. Hydrophobic impregnation reduces water absorption of facade materials and is thus presumed to decrease moisture related damages. Hydrophobic impregnation however also lowers the drying speed of the exposed facade, leaving mainly water vapour transfer to take place. This study examines the open porosity and capillary absorption coefficient of impregnated brick samples as well as the effect of hydrophobic impregnation on the vapour permeability of brick and mortar samples. The open porosity was measured with vacuum saturation test, the absorption coefficient was determined by water uptake tests, both done after one month of curing of the impregnated brick samples. The vapour permeability was `derived from cup tests and from drying tests. The resulting open porosity from brick samples indicates that the changes in the overall pore structure are minimal after impregnation. In addition, the ...
Journal of Building Physics
The application of computed tomography for characterizing the pore structure of building materials2019 •
Three-dimensional analyses of the pore structure of building materials are becoming progressively more important in recent years. The main goal is to obtain more accurate interpretations and simulations of their properties and performances. Computed tomography has proven to be an excellent and versatile tool to perform these analyses non-destructively. The reconstruction of the pore structure is of high importance for establishing accurate models, as it plays a crucial role in determining important characteristics of building materials such as their hygrothermal, mechanical, or acoustic properties. These models allow us to better understand the results of corresponding laboratory tests and in the near future might replace these time-consuming experiments. In this article, the strengths and weaknesses of computed tomography as a data acquisition technique are examined and discussed.
MATEC Web of Conferences
Hygrothermal Behavior of Earth-Based Materials: Experimental and Numerical Analysis2020 •
Bio-based building materials such as earth bricks are attracting renewed interest throughout the world due to their thermal and environmental properties. In this work, a numerical study of the hygrothermal behavior of building walls consist of compressed earth bricks (CEB) and stabilized earth bricks (SEB) was performed. A two-dimensional Luikov model for evaluating the temperature and the moisture migration in porous building materials was proposed. The coupled heat and moisture transfer problem was modeled. The governing equations of a mathematical model were solved numerically with the finite difference method. Input parameters in the model and their dependency on stabilizers content were determined by laboratory experiments. In order to specify the effect of chemical stabilization on the heat and mass transfer within studied materials, average moisture content and temperature were presented as a function of time. Results show that the addition of chemical stabilizers enhances th...
MATEC Web of Conferences
Non-isothermal moisture migration in a GCL composite liner system2021 •
Geosynthetic Clay liners (GCLs) are used extensively in waste management facilities as part of hydraulic and gas barriers since the bentonite, active component of GCLs, possesses a low conductivity when well hydrated. GCL hydration occurs in the unsaturated regime following the water retention curve of the GCL and subsoil (wetting and drying path of the WRC of the GCL and subsoil, respectively). Moreover, the GCL hydration is controlled/governed by factors such as applied stress condition, subsoil characteristics, and weather condition (temperature). This paper numerically studied the influence of temperature in the GCL hydration. The models were conducted using Vadose/W and simulations were calibrated with experimental results and further practical scenarios were then predicted. Five temperature conditions that resemble average and extreme weather were used (5°C, 10°C, 20°C, 50°C, 70°C, respectively). Results indicate that temperature influence the GCL hydration rate and the final ...
2021 •
This work aims to numerically study the desaturation process in a coarse-grained sandy deposit by means of air injection. It is well-known that the soil cyclic strength to liquefaction of a saturated, sandy deposit is positively affected by the presence of gas in the void space in either a dissolved or a free form. A numerical study is performed to investigate some of the factors affecting the desaturation advance and controlling the soil desaturation process by air injection. Among these factors are: a) soil-water characteristic curve and intrinsic permeability (hydraulic parameters), b) injection time, and c) standard approach to two injection wells placement. Only the standard mechanisms of biphasic flow are investigated (i.e., incompressible and isothermal biphasic flow in an isotropic homogeneous porous media with capillary effects).
Transport in Porous Media
A Multiscale Network Model for Simulating Moisture Transfer Properties of Porous Media1999 •
A multiscale network model is presented to model unsaturated moisture transfer in hygroscopic capillary-porous materials showing a broad pore-size distribution. Both capillary effects and water sorption phenomena, water vapour and liquid water transfer are considered. The multiscale approach is based on the concept of examining the porous space at different levels of magnification. The conservation of the water vapour permeability of dry material is used as scaling criterion to link the different pore scales. A macroscopic permeability is deduced from the permeabilities calculated at the different levels of magnification. Each level of magnification is modelled using an isotropic nonplanar 2D cross-squared network. The multiscale network simulates the enhancement of water vapour permeability due to capillary condensation, the hysteresis phenomenon between wetting and drying, and the steep increase of moisture permeability at the critical moisture saturation level. The calculated network permeabilities are compared with experimental data for calcium silicate and ceramic brick and a good agreement is observed.
MATEC Web of Conferences
Numerical simulations of overflow experiments on a model dike2019 •
Dike failure due to overtopping is one of the important factors, which should be considered in the dike designing process. Although the overflow is characterized by the relatively low risk of occurrence, in many cases dikes are totally destroyed or seriously damaged. An interesting phenomenon occurring during overflow is the trapping of air in pores of the unsaturated soil material. As the infiltration progresses from all sides, the air pressure in the unsaturated region increases, which may ultimately lead to damage of the dike structure. It happens when the air is expulsed in form of bursts and forms large macropores. Such a behaviour evidenced in laboratory experiments. In this study we attempt to simulate the evolution of stress field in the model dike subjected to overtopping. The results are in qualitative agreement with observations, showing that formation of the first macropores occurs in the direction perpendicular to the minor principal stress in the soil mass along the di...
MATEC Web of Conferences
Concrete spalling: Interaction between tensile behaviour and pore pressure during heating2013 •
Hydrophobic (or water-repellent) treatments have been proposed to mitigate moisture risks associated with Internal Wall Insulation when applied to solid masonry walls. This can reduce risks associated with moisture accumulation within the structure such as mould growth or the deterioration of joist ends and other embedded timber. However, such treatments slow down drying processes, and therefore may result in a net increase in moisture if the treatment is bypassed by e.g. cracks. Furthermore, such treatments have been linked with damage to external masonry surfaces. Freeze-thaw and salt crystallisation are the two main causes. Hygrothermal simulations may give some indication of risks but techniques to assess surface damage are either simplistic, impractical outside of the research environment, or both.
MATEC Web of Conferences
Pore structure and hygric properties of composite materials for radionuclide protection barriers2019 •
MATEC Web of Conferences
The influence of moisture on the energy performance of retrofitted walls2020 •
MATEC Web of Conferences
Properties of magnesium oxide boards used as sheathing in exterior wallsTransport in Porous Media
Modelling Unsaturated Moisture Transport in Heterogeneous Limestone2003 •
Sustainable Agriculture Reviews
Modelling the Hygrothermal Behaviour of Hemp Concrete: From Material to Building2020 •
MATEC Web of Conferences
Soil-water retention of highly expansive clay stabilized with a bio-polymerMaterials Science
The Influence of Interaction between Hydrophobic Stearate and Pozzolanic Additive on Hygric Transport and Storage Properties of Lime-based Plaster2018 •
Journal of Building Physics
Interlaboratory Comparison of the Measurement of Retention Curves1999 •
MATEC Web of Conferences
Numerical investigation of boiling and forced convection heat transfer in inclined porous enclosure using modified enthalpy formulation2018 •
2021 •
MATEC Web of Conferences
Chloride profiles with a peak – why and what are the consequences for predictions?Journal of Building Physics
Determination of the Liquid Water Diffusivity from Transient Moisture Transfer Experiments2004 •
MATEC Web of Conferences
Multiscale modelling for better hygrothermal prediction of porous building materialsEuropean Journal …
The combined influence of mineralogical, hygric and thermal properties on the durability of porous building stones2008 •
MATEC Web of Conferences
Modeling the soil-water retention curves for highly deforming soils2021 •
Building and Environment
Hygric and thermal properties of hemp-lime plasters2016 •
E3S Web of Conferences
Simulation of water movement and its distribution in a soil column under a water source using pore - scale network modelling2016 •
2021 •
MATEC Web of Conferences
Field monitoring and model predicted water balance of monolithic cover2021 •
Transport in Porous Media
Influence of Diffuse Damage on the Water Vapour Permeability of Fibre-Reinforced Mortar2012 •
Transport in Porous Media
A Dual-Permeability Approach to Study Anomalous Moisture Transport Properties of Cement-Based Materials2020 •
2015 •
Cement and Concrete Research
Water retention and gas relative permeability of two industrial concretes2012 •
2019 •
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Modelling of sorption hysteresis and its effect on moisture transport within cementitious materials2014 •
Environmental Earth Sciences
Experimental definition of microclimatic conditions based on water transfer and porous media properties for the conservation of prehistoric constructions: Cueva Pintada at Galdar, Gran Canaria, Spain2009 •
Water Resources Research
Water Saturation Relations and Their Diffusion‐Limited Equilibration in Gas Shale: Implications for Gas Flow in Unconventional Reservoirs2017 •
Wettability of nanofluids on crude oil contaminated soils at optimum conditions
Rita Monograph series or book on Wettability of nanofluids on crude oil contaminated soils at optimum conditions2015 •