scholarly journals Zeolite Lightweight Repair Renders: Effect of Binder Type on Properties and Salt Crystallization Resistance

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3760
Author(s):  
Milena Pavlíková ◽  
Adéla Kapicová ◽  
Adam Pivák ◽  
Martina Záleská ◽  
Michal Lojka ◽  
...  
Keyword(s):  
Water Vapor Permeability ◽  
High Water ◽  
Salt Crystallization ◽  
Vapor Permeability ◽  
High Porosity ◽  
Water Absorption Coefficient ◽  
Hydraulic Lime ◽  
Technical Parameters ◽  
Natural Hydraulic Lime ◽  
High Sorption

Rendering mortars with lightweight zeolite aggregates were designed and tested. The effect of the type of binder used was also researched. For the hardened mortars, macrostructural parameters, mechanical characteristics, hygric and thermal properties were assessed. Specific attention was paid to the analysis of the salt crystallization resistance of the developed rendering mortars. Quartz sand was fully replaced in the composition of mortars with zeolite gave materials with low density, high porosity, sufficient mechanical strength, high water vapor permeability and high water absorption coefficient, which are technical parameters required for repair rendering mortars as prescribed in the WTA directive 2-9-04/D and EN 998-1. Moreover, the zeolite enhanced mortars exhibit good thermal insulation performance and high sorption capacity. The examined rendering mortars were found to be well durable against salt crystallization, which supports their applicability in salt-laden masonry. Based on the compatibility of the repair materials with those originally used, the lime and natural hydraulic lime zeolite mortars can be used as rendering mortars for the repair of historical and heritage buildings. The cement-lime zeolite render is applicable for repair purposes only in the case of the renewal of masonry in which Portland cement-based materials were originally used.

scholarly journals Effect of Aggregate and Binder Type on the Functional and Durability Parameters of Lightweight Repair Mortars

2021 ◽  
Vol 13 (21) ◽  
pp. 11780
Author(s):  
Martina Záleská ◽  
Milena Pavlíková ◽  
Martin Vyšvařil ◽  
Zbyšek Pavlík
Keyword(s):  
Water Vapor ◽  
Salt Crystallization ◽  
Porous Space ◽  
High Porosity ◽  
Lightweight Aggregates ◽  
Expanded Perlite ◽  
Hydraulic Lime ◽  
Natural Hydraulic Lime ◽  
Binder Type ◽  
Repair Mortars

The subject matter of the work presented here is the development and evaluation of novel lightweight mortars that meet the functional and technical criteria imposed on repair mortars. In a broad experimental campaign, lime, natural hydraulic lime, and lime–cement mortars were designed and tested. Lightweight aggregate, expanded perlite, granules from expanded glass and zeolite were used as full replacements for quartz sand. The hardened mortars were tested at the ages of 28 days and 90 days. The conducted tests and analyses were focused on the assessment of structural, mechanical, hygric and thermal parameters. The salt crystallization resistance and effect of salt presence on the hygroscopicity of the investigated mortars were also investigated. The use of lightweight aggregates in the composition of mortars resulted in their high porosity, low density, satisfactory mechanical parameters, improved water vapor transmission capability and water absorption. The mortars with expanded perlite and glass granulate were ranked among thermal insulation mortars of classes T1 and T2, respectively. The use of lightweight aggregates enabled the development of mortars with great durability in terms of salt action, which was almost independent of binder type. The ability to accommodate water vapor was increased by the effect, i.e., the use of lightweight aggregates and the presence of salt in mortars increased porous space. Taking into account the compatibility, functional, and technical criteria, lime- and natural hydraulic lime-based lightweight mortarswere classified as repair mortars, providing improved thermal performance. The lime–cement lightweight plasters can be recommended only for repair of building structures where cement and lime–cement materials were original applied.

Polyurethane Electrospun Fiber Biomimetics Membrane for Constructing the Structure of Grain Layer with Good Breathability for Cattle Split Leather

2021 ◽  
Vol 116 (8) ◽  
Author(s):  
Nan Chen ◽  
Yanchun Li ◽  
Jianbo Qu ◽  
Jian-Yong Wang
Keyword(s):  
Water Vapor ◽  
Electrospun Fiber ◽  
Water Vapor Permeability ◽  
Waterborne Polyurethane ◽  
Vapor Permeability ◽  
High Porosity ◽  
Foam Layer ◽  
Fiber Morphology ◽  
Woven Structure ◽  
Superfine Fiber

The traditional thick coating on split leather does not have the ability to breathe like full grain leather.  The air and water vapor permeabilities of full grain leather are well known properties due to its fiber woven structure. Simulating the fiber morphology and weaving structure of the dermis or grain layer is very important to construct a top surface layer for split leather. In this paper, a PU (polyurethane) foam layer is put first on the split to enhance the adhesion of a second application of a superfine fibrous PU resin. This foam uses well-known waterborne polyurethane foaming technology. This dried foam has good breathability because of high porosity. A superfine fiber membrane is next put atop of the foam layer by using an electro-spun polyurethane resin. This second resin imitates collagen fibers in the network structure of the leathers’ grain layer. Thus, this resultant electrospun fiber biomimetics membrane simulated the grain layer of natural leather. SEM showed the morphology and structure of this electrospun fiber biomimetic membrane to be like that of the grain layer of natural leather. The porosity and apparent density were basically the same as the grain of leather, which were 63.65% and 583.878 kg/m3 respectively. The air and water vapor permeability of the biomimetics membrane were also as high as 2250 mL·cm-2·h-1 and 8753.02 μg·cm-2·h-1 respectively. Therefore, the biomimetics membrane largely restored the ability to breathe of split leather. Thus, this method simulates the performance and structure of full grain leather and is a novel method for industrial production

THE USE OF FLY ASH ALUMINOSILICATE MICROSPHERES IN THE LIME DRY MIXES FOR FINISHING AERATED CONCRETE

2017 ◽  
Vol 2 (3) ◽  
pp. 6-8 ◽  
Author(s):  
Логанина ◽  
Valentina Loganina ◽  
Фролов ◽  
Mikhail Frolov
Keyword(s):  
Thermal Conductivity ◽  
Water Vapor ◽  
Fly Ash ◽  
Water Vapor Permeability ◽  
High Water ◽  
Vapor Permeability ◽  
Low Thermal Conductivity ◽  
Aerated Concrete ◽  
Sufficient Strength

The application of ash microspheres in lime dry construction mixtures, designed for finishing aerated. It is shown that on the basis of dry ash mixtures with microspheres characterized by coating a sufficient strength, low thermal conductivity, high water vapor permeability, resistance to the action of the slanting rain.

scholarly journals Thermo-mechanical Characterization of Insulating Bio-plasters Containing Recycled Volcanic Pyroclasts

2020 ◽  
Vol 14 (1) ◽  
pp. 66-77
Author(s):  
Loredana Contrafatto ◽  
Salvatore Gazzo ◽  
Antonio Purrazzo ◽  
Antonio Gagliano
Keyword(s):  
Thermal Properties ◽  
Volcanic Ash ◽  
Mechanical Characterization ◽  
Construction Material ◽  
Sustainable Construction ◽  
Mechanical And Thermal Properties ◽  
Water Absorption Coefficient ◽  
Hydraulic Lime ◽  
Natural Hydraulic Lime

Aim: The research proposes the reuse of volcanic wastes in the production of lightened and insulating bio-plasters. Introduction: The goal is the production of a novel sustainable construction material that reduces the environmental impact. Methods: Four mixtures were designed. The recycled Volcanic Ash was used in combination with two bio-compatible binders; basically Natural Hydraulic Lime (NHL) or calcium hydroxide blended with a commercial Portland cement (CH-CEM). To improve thermal properties, CH-CEM mixtures were treated with an Air Entraining Agent (AEA) in two different percentages and a breathable resin (R). The main physical, mechanical and thermal properties were experimentally determined. Results: The results of such analysis indicate that the mixture NHL, realized using hydraulic lime as a binder, do not satisfy the threshold of the water absorption coefficient, exceeding the limit established by UNI EN 998-1 standard. Conclusion: On the contrary, one of the mixtures CH-CEM, containing both AEA and R, is suitable for use as lightweight plastering mortar and also satisfies the requirements for insulating mortars.

scholarly journals The Role of Structure and Interactions in Thermoplastic Starch–Nanocellulose Composites

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3186
Author(s):  
Emília Csiszár ◽  
Dávid Kun ◽  
Erika Fekete
Keyword(s):  
Composite Films ◽  
Water Vapor Permeability ◽  
High Water ◽  
Thermoplastic Starch ◽  
Vapor Permeability ◽  
Visible Spectroscopy ◽  
Different Types ◽  
Additional Water ◽  
Human Eyes

Composite films were fabricated by using cellulose nanocrystals (CNCs) as reinforcement up to 50 wt% in thermoplastic starch (TPS). Structure and interactions were modified by using different types (glycerol and sorbitol) and different amounts (30 and 40%) of plasticizers. The structure of the composites was characterized by visible spectroscopy, Haze index measurements, and scanning electron microscopy. Tensile properties were determined by tensile testing, and the effect of CNC content on vapor permeability was investigated. Although all composite films are transparent and can hardly be distinguished by human eyes, the addition of CNCs somewhat decreases the transmittance of the films. This can be related to the increased light scattering of the films, which is caused by the aggregation of nanocrystals, leading to the formation of micron-sized particles. Nevertheless, strength is enhanced by CNCs, mostly in the composite series prepared with 30% sorbitol. Additionally, the relatively high water vapor permeability of TPS is considerably decreased by the incorporation of at least 20 wt% CNCs. Reinforcement is determined mostly by the competitive interactions among starch, nanocellulose, and plasticizer molecules. The aging of the films is caused by the additional water uptake from the atmosphere and the retrogradation of starch.

scholarly journals Influence of Hydration State on Permeation Testing and Vapor Transport Properties of Protective Clothing Layers

2009 ◽  
Vol 4 (4) ◽  
pp. 155892500900400 ◽  
Author(s):  
Phillip W. Gibson ◽  
Heidi L. Schreuder-Gibson
Keyword(s):  
Water Vapor ◽  
Protective Clothing ◽  
Chemical Warfare Agents ◽  
Water Vapor Permeability ◽  
High Water ◽  
Chemical Warfare ◽  
Vapor Permeability ◽  
Liquid Form ◽  
Vapor Flux ◽  
Warfare Agents

Protective clothing systems composed of permselective polymer film laminates are an alternative to standard air-permeable garments based on activated carbon. These polymer layers are designed with high water vapor permeation rates and low permeation of chemical warfare agents. Polymer films that have a significant water vapor flux usually also have an affinity for water, and will hydrate and swell significantly at high humidity levels. The polymer film's increase in water content has the potential to affect the transport rate of chemical warfare agents in vapor and liquid form, and usually also has a large effect on the intrinsic water vapor permeability of the membrane.

scholarly journals Polybenzimidazole-based mixed membranes with exceptionally high water vapor permeability and selectivity

2017 ◽  
Vol 5 (41) ◽  
pp. 21807-21819 ◽  
Author(s):  
F. H. Akhtar ◽  
M. Kumar ◽  
L. F. Villalobos ◽  
H. Vovusha ◽  
R. Shevate ◽  
...  
Keyword(s):  
Water Vapor ◽  
Gas Separation ◽  
Water Vapor Permeability ◽  
High Water ◽  
Mixed Matrix Membranes ◽  
Vapor Permeability ◽  
Mixed Matrix ◽  
Matrix Membranes

Mixed matrix membranes containing polybenzimidazole and titania-based fillers with different morphologies are fabricated and tested for efficient water vapor/gas separation applications.

scholarly journals The use of an internal airtight membrane in CLT external wall in terms of hygrothermal performance

2021 ◽  
Vol 2069 (1) ◽  
pp. 012208
Author(s):  
V. Kukk ◽  
J. Kers ◽  
T. Kalamees
Keyword(s):  
Water Vapor Permeability ◽  
Stochastic Approach ◽  
High Water ◽  
Vapor Permeability ◽  
Diffusion Resistance ◽  
Mold Growth ◽  
External Wall ◽  
Hygrothermal Performance ◽  
Dry Out ◽  
The Impact

Abstract This study focused on the dry-out capacity of the vapor-permeable CLT (cross-laminated timber) external wall and the impact of using an internal airtight membrane. The results of the work were obtained first from the field measurements, after which the simulation model was created and validated, and the hygrothermal performance of the wall was analyzed by a stochastic approach. The results of this showed that the CLT dries out quickly and safely in a wall assembly with a high water vapor permeability, even with the large range of initial CLT MC (13-25%). When an additional airtight layer with high vapor diffusion resistance (Sd of 244 m) is added between the insulation and the CLT, the dry-out capacity of the CLT decreases significantly and there is a high probability of mold growth on the CLT surface. The risk of mold growth can be prevented when the vapor resistance (Sd) of the airtight layer is reduced to 1.5 m in a case where initial CLT MC is up to 25% and in a case where initial MC is up to 20%, the vapor resistance of an airtight layer must be reduced to 3 m.

scholarly journals Synthesis of Silphenylene-Containing Siloxane Resins Exhibiting Strong Hydrophobicity and High Water Vapor Barriers

Coatings ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 481
Author(s):  
Chen ◽  
Yi ◽  
Wu ◽  
Tan ◽  
Xu ◽  
...  
Keyword(s):  
Contact Angle ◽  
Water Vapor ◽  
Water Contact Angle ◽  
Water Vapor Permeability ◽  
Barrier Properties ◽  
High Water ◽  
Vapor Permeability ◽  
One Pot ◽  
Water Contact ◽  
Thermal Stabilities

The novel phenylenedisilane, 1,4-bis(dimethoxyphenylsilyl)benzene (BDMPD), was successfully synthesized via the reaction between trimethoxyphenylsilane (TMPS) and a Grignard reagent originating from 1,4-dibromobenzene. In comparison to common Grignard reactions, this process was a facile one-pot method. 1H NMR spectroscopy, FT-IR measurements, and elemental analysis confirmed the predicted structure of BDMPD. In addition, vinyl-terminated polysiloxanes containing silphenylene units (VPSSP), which were hydrolytically copolymerized from BDMPD, TMPS, and divinyltetramethyldisiloxane, exhibited excellent thermal stabilities (T10%: 502 °C, Rw%: 76.86 beyond 700 °C) and suitable refractive indices (1.542). Furthermore, water contact angle and water vapor permeability tests confirmed that the fully cured siloxane resins containing VPSSP-based silphenylene units exhibited strong hydrophobicity (water contact angle: 119°) and superior water vapor barrier properties, thereby indicating their potential to serve as strong waterproof coatings for moisture-proof applications or as adhesives for use in immersed equipment.

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