scholarly journals Modeling Water Adsorption and Retention of Building Materials From Pore Size Distribution

2019 ◽  
Vol 7 (6) ◽  
pp. 547-556
Author(s):  
Abdelkrim Trabelsi ◽  
Zakaria Slimani ◽  
Akli Younsi ◽  
Joseph Virgone ◽  
Rafik Belarbi
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Building Materials ◽  
Water Adsorption

On the characterization of pore size distribution of building materials

2017 ◽  
Vol 41 (3) ◽  
pp. 247-263 ◽  
Author(s):  
LF Dutra ◽  
N Mendes ◽  
PC Philippi
Keyword(s):  
Relative Humidity ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Building Materials ◽  
Mercury Porosimetry ◽  
Energy Performance ◽  
Volume Distribution ◽  
Wide Range

Moisture affects significantly the energy performance of air conditioning systems, the durability of materials, and the health of occupants. One way of reducing those effects, without increasing the energy costs, is by means of using porous material ability of absorbing and releasing moisture from/to the adjacent environment, which attenuates the indoor relative humidity variation. This natural ability is intrinsically related to the porous microstructure. Therefore, the characterization of the pore space is an important research theme in the building physics area. This article aims to present a method for obtaining the pore size distribution based on adsorption isotherms and mercury porosimetry data. First, the theoretical formulation based on the Gibbs free energy for a two-phase (liquid–vapor) system, using the De Boer and Zwikker model, is presented, allowing the calculation of the critical adsorbed thickness for pore filling, critical radius, adsorbed moisture content, capillary condensation content, available surface for adsorption, and the distribution of micropores for a wide range of radius. The adsorption isotherm curve is estimated for high relative humidity values through mercury porosimetry, along with the adsorption curve obtained from the experiment. The pore volume distribution calculated by this method can be used to estimate transport coefficients for liquid and vapor phases.

Water Adsorption in Nanoporous Carbon Characterized by in Situ NMR: Measurements of Pore Size and Pore Size Distribution

2014 ◽  
Vol 118 (16) ◽  
pp. 8474-8480 ◽  
Author(s):  
Hai-Jing Wang ◽  
Alfred Kleinhammes ◽  
Thomas P. McNicholas ◽  
Jie Liu ◽  
Yue Wu
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Water Adsorption ◽  
Nanoporous Carbon ◽  
In Situ Nmr

Moisture Buffering Potential of Plasters for Energy Efficiency in Modern Buildings

2017 ◽  
Author(s):  
Jan Fořt ◽  
Magdaléna Doleželová ◽  
Robert Černý
Keyword(s):  
Relative Humidity ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Open Porosity ◽  
Building Materials ◽  
High Energy ◽  
Building Envelopes ◽  
Moisture Buffering ◽  
Ventilation Systems

Moisture level significantly affects durability of constructions, their thermal performance and quality of indoor air. Since building envelopes are subjected to a moisture gradient, additional ventilation systems are employed to maintain relative humidity on the desired level. Although modern advanced ventilation systems provide sufficient air exchange rate, their wider application is in conflict with sustainability development principles due to high energy demands. Moreover, according to the European legislation related to the Nearly Zero Energy Buildings (European Directives 2002/91/EC and 2010/31/EU), air tightness of building envelopes in order to provide high thermal resistance leads to large moisture loads in building interiors. Among other factors, a high level of relative humidity has negative effect on the work efficiency and health of building inhabitants. A detailed insight into building materials behavior during cyclic moisture loading was accessed within this study. The moisture buffering values of three interior plasters were investigated in order to describe influence of plasters on moderation of indoor environment. Particular materials were loaded according to the NORDTEST protocol by 8/16 h loading schema at 70/30% RH. Here, the excellent moisture buffer classification was obtained for lightweight perlite plaster (PT) with the highest total open porosity. However, contrary to the higher total open porosity of renovation plaster (PS), the core plaster (CP) achieved higher moisture buffer capacity than PS. This discrepancy refers to the influence of the pore size distribution which is, besides the total open porosity, essential for a detailed characterization of moisture buffering potential of building materials. Based on the results of Mercury intrusion porosimetry, a correlation between pore size distribution and moisture buffer value was revealed.

Influence of pore size distribution on water adsorption on silica gels

2009 ◽  
Vol 17 (4) ◽  
pp. 409-416 ◽  
Author(s):  
J. Alcañiz-Monge ◽  
M. Pérez-Cadenas ◽  
D. Lozano-Castelló
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Water Adsorption ◽  
Silica Gels

scholarly journals Measurement of pore size distribution of building materials by thermal method

2020 ◽  
Vol 245 ◽  
pp. 118417
Author(s):  
Nicolas Dujardin ◽  
Thouraya Salem ◽  
Vincent Feuillet ◽  
Magali Fois ◽  
Laurent Ibos ◽  
...  
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Building Materials ◽  
Thermal Method

scholarly journals The Influence of Casein Protein Admixture on Pore Size Distribution and Mechanical Properties of Lime-Metakaolin Paste

Buildings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 530
Author(s):  
Przemysław Brzyski ◽  
Zbigniew Suchorab ◽  
Grzegorz Łagód
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Building Materials ◽  
Total Porosity ◽  
Organic Polymer ◽  
Partial Replacement ◽  
Average Pore

Biopolymers based on proteins are applied in the building materials technology to modify and improve their selected properties. These polymers are designed as natural admixtures that improve the workability of materials. Casein is an example of a protein-based organic polymer. It is a protein obtained from cow’s milk. The paper aimed at investigating the prospects of enhancing the strength properties of a binder prepared on a basis of metakaolin and hydrated lime. The mix was modified with powdered technical casein at 0.5%, 1%, 3%, and 5% as a partial replacement for the binder mix by mass. The study involved investigating the effect of the applied natural admixture on the flexural and compressive strengths, as well as pore size distribution. The average pore diameter decreased in the recipes with casein in the amount of 0.5% and 1%, while it increased when the amount of casein equaled 3% and 5%. Only the 0.5% casein admixture caused a decrease in the total porosity. The results show a clear dependence of the strength parameters on porosity. The admixture of casein significantly increased the flexural strength of the pastes, and decreased the compressive strength. The highest increase in flexural strength (by 205.7%) was caused by the admixture of 0.5% casein, while the greatest decrease in compressive strength (by 28%) was caused by the 3% casein admixture. The flexural strength was enhanced, i.a., due to the improved adhesion and mutual bonding of lime particles, resulting from the application of a sticky admixture. No notable difference was indicated during carbonation by the phenolphthalein test. The lime binder is characterized by a slow setting process and low mechanical strength. The results of the research showed the possibility of improving the flexural strength using small amounts of natural admixture, which may broaden the scope of application of this binder.

pyGAPS: A Python-Based Framework for Adsorption Isotherm Processing and Material Characterisation

2019 ◽  
Author(s):  
Paul Iacomi ◽  
Philip L. Llewellyn
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Surface Area ◽  
Isosteric Heat ◽  
Material Characterisation ◽  
Mixture Adsorption ◽  
Surface Energetics ◽  
Adsorption Processing ◽  
User Friendly

Material characterisation through adsorption is a widely-used laboratory technique. The isotherms obtained through volumetric or gravimetric experiments impart insight through their features but can also be analysed to determine material characteristics such as specific surface area, pore size distribution, surface energetics, or used for predicting mixture adsorption. The pyGAPS (python General Adsorption Processing Suite) framework was developed to address the need for high-throughput processing of such adsorption data, independent of the origin, while also being capable of presenting individual results in a user-friendly manner. It contains many common characterisation methods such as: BET and Langmuir surface area, t and α plots, pore size distribution calculations (BJH, Dollimore-Heal, Horvath-Kawazoe, DFT/NLDFT kernel fitting), isosteric heat calculations, IAST calculations, isotherm modelling and more, as well as the ability to import and store data from Excel, CSV, JSON and sqlite databases. In this work, a description of the capabilities of pyGAPS is presented. The code is then be used in two case studies: a routine characterisation of a UiO-66(Zr) sample and in the processing of an adsorption dataset of a commercial carbon (Takeda 5A) for applications in gas separation.

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