Hygric Properties of HPC with Natural Pozzolana

2016 ◽  
Vol 677 ◽  
pp. 93-97 ◽  
Author(s):  
Jaroslava Koťátková ◽  
Monika Čáchová ◽  
Dana Koňáková ◽  
Eva Vejmelková
Keyword(s):  
Water Vapour ◽  
High Performance ◽  
High Performance Concrete ◽  
Diffusion Resistance ◽  
Supplementary Cementitious Material ◽  
Water Vapour Transport ◽  
Water Vapour Diffusion ◽  
Natural Pozzolana ◽  
Vapour Diffusion ◽  
Liquid Water Transport

The water vapour transport and the liquid water transport of high performance concrete (HPC) with the content of natural pozzolana are the described in this paper. Studied properties are presented by means of water vapour diffusion coefficient, water vapour diffusion resistance factor and absorption coefficient respectively. The natural pozzolana (NP), namely natural zeolite, is used as supplementary cementitious material which affects the durability properties of the end product. The obtained results revealed the effectiveness of NP in the terms of both studied properties when used in small amounts, i.e. at about 20% of cement weight. On the other hand substitutions higher than 40% result in worsening of the resistance of the concrete to water and water vapour ingress and its movement trough the material.

Untersuchungen zum Diffusionswiderstand von Holzwerkstoffen | Diffusion resistance of timber materials

2005 ◽  
Vol 156 (3-4) ◽  
pp. 100-103
Author(s):  
Rudolf Popper ◽  
Peter Niemz ◽  
Gerhild Eberle
Keyword(s):  
Relative Humidity ◽  
Water Vapour ◽  
Middle Lamella ◽  
Solid Wood ◽  
Diffusion Resistance ◽  
Water Vapour Diffusion ◽  
Wood Panels ◽  
Vapour Diffusion ◽  
Wet Climate ◽  
Panel Thickness

The water vapour diffusion resistance of timber materials were tested in a wet climate (relative humidity ranging from 100%to 65% at 20 °C) and in a dry climate (relative humidity ranging from 0% to 65% and from 0% to 35% at 20 °c) with variation by relative humidity and vapour pressure gradient. The diffusion resistance of multilayer solid wood panels lies under or within the range of the solid wood (spruce), tending even to a lower range. This can be attributed to the loosely inserted middle lamella of the used solid wood panels, which were not correctly glued by the manufacturer. The diffusion resistance of the solid wood panels increases with decreasing moisture content and decreasing panel thickness, as well as with increasing water vapour gradient from 818 to 1520 Pa. There were clear differences between the tested timber materials. The diffusion resistance of particle composites is strongly dependent on the specific gravity. Due to laminar particles OSBs(Oriented Strand Boards) have a larger diffusion resistance than chipboards. The water vapour diffusion resistance of OSBs lies within the range of plywood.

Effects of exposure on water relations and photosynthesis of western hemlock in habitat forms

1976 ◽  
Vol 6 (1) ◽  
pp. 40-48 ◽  
Author(s):  
R. A. Keller ◽  
E. B. Tregunna
Keyword(s):  
Light Intensity ◽  
Water Content ◽  
Water Vapour ◽  
Western Hemlock ◽  
Diffusion Resistance ◽  
The Sun ◽  
Evaporative Demand ◽  
Photosynthetic Rates ◽  
Water Vapour Diffusion ◽  
Vapour Diffusion

Measurements of relative turgidity, transpiration rates, and photosynthetic rates on sun-grown and shade-grown western hemlock (Tsugaheterophylla (Raf.) Sarg.) were used to indicate effects of varying degrees of exposure.The sun-adapted form had low photosynthetic rates but maintained its water content under conditions of high evaporative demand. The shade-adapted form desiccated under exposed conditions, and in contrast with the sun-adapted form, its water vapour diffusion resistance decreased with increasing light intensity.

Measuring of Equivalent Air Layer Thickness of Nanofibre Textiles

2016 ◽  
Vol 714 ◽  
pp. 192-195 ◽  
Author(s):  
Martin Černohorský ◽  
Petr Semerák ◽  
Petra Tichá
Keyword(s):  
Layer Thickness ◽  
Water Vapour ◽  
Measurement Method ◽  
Measurement Methods ◽  
Diffusion Resistance ◽  
Sheet Materials ◽  
Water Vapour Diffusion ◽  
Vapour Diffusion ◽  
Method Of Measurement ◽  
Open Materials

This article deals with selecting the appropriate method of measurement water vapour diffusion through nanofibre textiles. Parameter for comparison of different sheet materials for its ability to brake the water vapour is a equivalent air layer thickness value Sd. The equivalent air layer thickness Sd [m] expresses the equivalent air layer thickness of the air layer, which would have the same diffusion resistance as the thickness of the measured material. It is necessary to choose the appropriate measurement method for determining the value Sd with diffusion open materials such as nanofibre materials. This article compares the outcomes of two measurement methods – Dry Cup Method and Tube Method. The measurements were carried out on a sample from nanofibre textiles based on PVDF.

Determination of Hygric Properties of Hollow Brick Block as a Function of Moisture Content

2014 ◽  
Vol 982 ◽  
pp. 54-58
Author(s):  
Tomáš Korecký ◽  
Miloš Jerman ◽  
Robert Černý
Keyword(s):  
Adsorption Isotherm ◽  
Moisture Content ◽  
Water Vapour ◽  
Moisture Diffusivity ◽  
Diffusion Resistance ◽  
Water Vapour Diffusion ◽  
Vapour Diffusion ◽  
Hollow Brick ◽  
Hygric Properties

In the paper is presented calculation of hygric properties of hollow brick block. Namely it is adsorption isotherm, water vapour diffusion resistance factor and moisture diffusivity. The brick block cavities was filled only by air. In first step the properties of brick body were measured. Then the properties of the whole brick block were calculated by using homogenisation techniques.

scholarly journals Water vapour diffusion resistance factor of Phyllostachys edulis (Moso bamboo)

2017 ◽  
Vol 141 ◽  
pp. 216-221 ◽  
Author(s):  
Puxi Huang ◽  
Eshrar Latif ◽  
Wen-Shao Chang ◽  
Martin P. Ansell ◽  
Mike Lawrence
Keyword(s):  
Water Vapour ◽  
Resistance Factor ◽  
Moso Bamboo ◽  
Diffusion Resistance ◽  
Phyllostachys Edulis ◽  
Water Vapour Diffusion ◽  
Vapour Diffusion

scholarly journals Ground Glass Pozzolan in Conventional, High, and Ultra-High Performance Concrete

2018 ◽  
Vol 149 ◽  
pp. 01005 ◽  
Author(s):  
Arezki Tagnit-Hamou ◽  
Ablam Zidol ◽  
Nancy Soliman ◽  
Joris Deschamps ◽  
Ahmed Omran
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Ground Glass ◽  
Strengthening Effect ◽  
Ultra High Performance Concrete ◽  
Conventional Concrete ◽  
Supplementary Cementitious Material ◽  
Pozzolanic Material ◽  
And Performance

Ground-glass pozzolan (G) obtained by grinding the mixed-waste glass to same fineness of cement can act as a supplementary-cementitious material (SCM), given that it is an amorphous and a pozzolanic material. The G showed promising performances in different concrete types such as conventional concrete (CC), high-performance concrete (HPC), and ultra-high performance concrete (UHPC). The current paper reports on the characteristics and performance of G in these concrete types. The use of G provides several advantages (technological, economical, and environmental). It reduces the production cost of concrete and decrease the carbon footprint of a traditional concrete structures. The rheology of fresh concrete can be improved due to the replacement of cement by non-absorptive glass particles. Strength and rigidity improvements in the concrete containing G are due to the fact that glass particles act as inclusions having a very high strength and elastic modulus that have a strengthening effect on the overall hardened matrix.

Properties of high performance concrete containing fine-ground ceramics as supplementary cementitious material

2012 ◽  
Vol 34 (1) ◽  
pp. 55-61 ◽  
Author(s):  
Eva Vejmelková ◽  
Martin Keppert ◽  
Pavla Rovnaníková ◽  
Michal Ondráček ◽  
Zbyněk Keršner ◽  
...  
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Cementitious Material ◽  
Supplementary Cementitious Material
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