scholarly journals The Effect of Cement Addition on Water Vapour Resistance Factor of Rammed Earth

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2249
Author(s):  
Piotr Narloch ◽  
Wojciech Piątkiewicz ◽  
Barbara Pietruszka
Keyword(s):  
Water Vapour ◽  
Construction Materials ◽  
Resistance Factor ◽  
Soil Particle ◽  
Rammed Earth ◽  
Diffusion Resistance ◽  
Particle Sizes ◽  
Literature Analysis ◽  
Test Results ◽  
Water Vapour Resistance

The article aims to determine the effect of cement addition on the water vapour resistance factor of stabilized rammed earth. Literature analysis indicates that different earthen materials show large differences in water vapour resistance factor values. The high diffusion resistance of concrete concerning other construction materials suggests that cement will be one of the factors significantly affecting these values. The paper presents water vapour resistance factor test results of rammed earth with various soil particle sizes and cement contents. The obtained results showed that an increase of cement addition increases the diffusion resistance of the material. However, the diffusion resistance of cement stabilized rammed earth is still low compared to concrete.

scholarly journals Research of Wood Waste as a Potential Filler for Loose-Fill Building Insulation: Appropriate Selection and Incorporation into Polyurethane Biocomposite Foams

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5336
Author(s):  
Nerijus Augaitis ◽  
Saulius Vaitkus ◽  
Sylwia Członka ◽  
Agnė Kairytė
Keyword(s):  
Thermal Conductivity ◽  
Water Absorption ◽  
Water Vapour ◽  
Wood Waste ◽  
Diffusion Resistance ◽  
Water Vapour Diffusion ◽  
Recycling Potential ◽  
Water Vapour Resistance ◽  
The Stability ◽  
Loose Fill

Currently, the recycling potential of wood waste (WW) is still limited, and in a resource efficiency approach, recycling WW in insulation materials, such as polyurethane (PUR), appears as an appropriate solution. It is known that the quality of WW is the main aspect which influences the stability of the final products. Therefore, the current study analyses different WW-based fillers as possible modifiers for polyurethane biocomposite foams for the application as loose-fill materials in building envelopes. During the study of WW-based fillers, it was determined that the most promising filler is wood scobs (WS) with a thermal conductivity of 0.0496 W/m·K, short-term water absorption by partial immersion—12.5 kg/m2, water vapour resistance—0.34 m2·h·Pa/mg and water vapour diffusion resistance factor—2.4. In order to evaluate the WS performance as a filler in PUR biocomposite foams, different ratios of PUR binder and WS filler (PURb/WS) were selected. It was found that a 0.40 PURb/WS ratio is insufficient for the appropriate wetting of WS filler while a 0.70 PURb/WS ratio produced PUR biocomposite foams with the most suitable performance: thermal conductivity reduced from 0.0523 to 0.0476 W/m·K, water absorption—from 5.6 to 1.3 kg/m2, while the compressive strength increased from 142 to 272 kPa and the tensile strength increased from 44 to 272 kPa.

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

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.

THE PEACH REPLANT PROBLEM IN ONTARIO: V. THE RELATION OF PARASITIC NEMATODES TO REGIONAL DIFFERENCES IN SEVERITY OF PEACH REPLANT FAILURE

1958 ◽  
Vol 36 (1) ◽  
pp. 125-134 ◽  
Author(s):  
W. B. Mountain ◽  
H. R. Boyce
Keyword(s):  
Regional Differences ◽  
Previous History ◽  
Soil Particle ◽  
Parasitic Nematodes ◽  
Particle Sizes ◽  
Pratylenchus Penetrans ◽  
Essex County ◽  
Soil Population ◽  
History Of ◽  
Replant Problem

Peach production in Ontario is largely restricted to the Niagara Peninsula and Essex County, areas that are separated by some 200 miles but have a similar climate. The peach replant problem has been much more serious in Essex County than in the Niagara Peninsula. A survey of mature peach orchards showed that Pratylenchus penetrans (Cobb, 1917) Sher & Allen, 1953, is considerably more prevalent in peach soils in Essex County than in the Niagara Peninsula. In both areas, orchards that had a previous history of the replant problem had three to four times greater soil population of P. penetrans than those with no such history. Soils of finer texture were shown to limit the populations of P. penetrans, and the relatively low numbers of this nematode in the Niagara Peninsula appear to result from the influence of the finer soils prevailing in that region. The effect of different soil-particle sizes on the build-up of P. penetrans may explain the distribution of the peach replant problem in Ontario.

scholarly journals Space Charge Property of Polyethylene/Silica Nanocomposites at Different Elongations

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Can Wang ◽  
Youyuan Wang ◽  
Peng Fan ◽  
Ruijin Liao
Keyword(s):  
Particle Size ◽  
Space Charge ◽  
Dipole Model ◽  
Particle Sizes ◽  
Test Results ◽  
Silica Nanocomposites ◽  
Induced Dipole ◽  
Interface Characteristics ◽  
Space Charge Distribution ◽  
Charge Property

This paper prepares polyethylene/silica nanocomposites with concentrations of 3 wt% and 5 wt% by using silicon dioxide (SiO2) nanopowder (nanosilica) with particle sizes of 15 and 50 nm. Samples whose elongations are 3%, 6%, and 10% are prepared. Pulsed electroacoustic technique is applied to evaluate the space charge distribution in samples. Test results show that homocharge near electrodes is generated in the polyethylene/silica nanocomposites. Nanocomposites with a nanoparticle concentration of 3 wt% and particle size of 15 nm suppress the accumulation of space charge effectively. The amount of space charge in the samples increases with the increase in elongation. At an elongation of 10%, packet-like space charge is generated in polyethylene/silica nanocomposites with the concentration of 5 wt% and particle sizes of 15 and 50 nm. The packet-like space charge in nanocomposites whose particle size is 50 nm is more obvious than that in nanocomposites whose particle size is 15 nm. The experiment results are explained by applying interface characteristics, dipole model, and induced dipole model.

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.

Experimental Study on the Interaction Effect of Sulfate Ions and Chloride Ions on Reinforcement Corrosion in Marine Environment

2017 ◽  
Author(s):  
Yi Huang ◽  
Yunze Xu ◽  
Xiaona Wang ◽  
Shide Song ◽  
Lujia Yang
Keyword(s):  
Passive Film ◽  
Pore Solution ◽  
Construction Materials ◽  
Chloride Ions ◽  
Localized Corrosion ◽  
Test Results ◽  
Reinforcement Corrosion ◽  
Marine Structures ◽  
Sulfate Ions ◽  
Corrosion Risk

Reinforced concrete is one of the most widely used construction materials for marine structures. Due to the abundance of the aggressive ions such as chloride ions and sulfate ions in the seawater, the reinforcement exposed to the marine and costal environment are exposed to a high corrosion risk. Localized corrosion will occur once the passive film on the rebar is damaged. In this work, the corrosion behavior of the steel in the simulated pore solution containing with both sulfate ions and chloride ions are studied by using cyclic potentialdynamic polarization methods and the corrosion morphologies observed using scanning electron microscope (SEM). The test results show that the initial rebar corrosion is caused by the absorption of the chloride ions in the passive film. The sulfate ions nearly had no effect on the corrosion of the rebar in pore solution and it can further mitigate the pitting corrosion in chloride containing pore solution.

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