Papers by Keyword: Water Resistance

Abstract: Ventilated facades are widely used in modern energy efficient building, and it leads to topical issue whether it is important or not to stick to assembling terms of such kinds of facades. The first thing to do during the ventilated facades installation is to built in the mineral-cotton insulant which will be later protected by vapor proof material. Thus, the shield obtained on the exterior side of the building in the aggregate with ventilated clearance and facing material form a system with high insulation and resistant to environmental attacks. This article observed a situation in which the terms of ventilated facades installation were broken after the primary stage (not more than 90 days). The works were stopped for 1.5 year after fixing the heat-insulation material to the inclosing walls of the building. As a result, insulants were exposed to significant temperature and humidity changes, wind forces and UV rays. The main objective of this research is to determine the suitability of insulating material for further use taking into account changes in its basic parameters, which are determined by laboratory tests.

Abstract: Magnesium cement-based straw board is made of chloride-oxy-magnesium concrete as gel phase, a new building material with straw as reinforcing phase. The effects of molar ratio of MgO and MgCl₂ on the static bending strength, softening coefficient and start time back to halogen moisture absorption of magnesium cement-based straw board are analyzed in detail. The result showed that,when n(MgO)/n(MgCl₂)=7(molar ratio),the mechanical properties and water resistance are the best, hydration products at this time is dominated by 518 phase.

Abstract: Styrene (SM), methyl methacrylate (MMA), and butyl acrylate (BA) were used to synthesize a polyacrylic emulsion by core-shell emulsion polymerization. The solid content of the emulsion reached 40% using reasonable reactive emulsifier contents and feeding modes. Then, two kinds of fibers (recovered and hardwood fiber) were respectively dispersed, coated, and dried with emulsion. Finally, fiber-based water-resistant material was successfully fabricated. The experimental results showed that under the conditions of a mass ratio of polyacrylic emulsion to fiber of 2:1, the Cobb value of the material reached 7.1 g/m² and 10.8 g/m² respectively. Cobb value of recovered fiber material was more stable than hardwood fiber, and stayed in a lower variation scope on the whole. Using scanning electron microscopy (SEM) to observe the surface morphology of products. The SEM results proved that, the polyacrylic emulsion filled the gaps between fibers, decreased the porous structure. This filling effect led to a continuous structure, and kept the water from infiltrating inside of the material. On the other hand, for the short fiber in recovered fiber material arranged closer, the water resistance of the material was further enhanced.

Abstract: A substantial part of the world building heritage has been performed by earthen building. The durability of this existing heritage and mainly of the new buildings built with earth is particularly conditioned by the erosion caused by water action, especially in countries with high levels of rainfall. This research aims to contribute to the increase of knowledge about the ancient building techniques that provide enhanced durability. It is possible to analyse the ancestral practices used to protect the earth material from the water action in order to understand how the old earthen buildings were preserved over the centuries, resisting to harsh weather conditions. Among these techniques are: the incorporation of biopolymers (such as oils or fats from animal or vegetable origin); the addition of some minerals; and the earth stabilization with lime. However, this knowledge seems to be forgotten, probably due to the prejudice related to earthen constructions, which several times are associated with a poor building. This research also focuses on the study of new methods of earth stabilization with lime and biopolymers, adapting the ancient knowledge to improve the durability related to the water action. Therefore, alternative solutions can be obtained to improve the performance of earthen buildings, mainly the resistance of the material in the presence of water, reducing its permeability to water. In addition, with the proposed solutions it is possible to obtain good levels of water vapour permeability, one of the major advantages of the construction with earth.

Abstract: Data about regularities of influence of filler, based on the calcium hydrosilicate, on properties of limy dry construction mixes and coverings in their basis are given. Higher water resistance of limy coverings with application of containing silicate filler is established.The conducted researches established efficiency of application in a compounding of limy dry construction mixes (DCM) the nanostructuring additives based on aluminosilicates [1, 2]. For regulation of structure and properties of limy dry construction mixes (DCM), intended for restoration of historical building, and also finishing of again constructed facilities, we offered to enter into their compounding an additive based on the synthesized hydrosilicates (HSC) [3, 4].Hydrosilicates of calcium (HSC) are received by synthesis from liquid sodium glass in the presence of calcium chloride CaCl₂ with the subsequent drying of sediment at a temperature 105-300°C and its crushing. Studying of material composition of the filler, made by methods of the X-ray phase analysis (RFA) and infrared (IK) spectroscopy, and also structure on the electronic scanning microscope of PhenomTM G2 pro showed the existence in synthesizable material the calcium silicates of various basicity.The conducted researches show that the filler based on HSC possesses hydraulic activity. The activity of filler, defined according to a technique [5], makes 195-250 mg/g depending on the synthesis mode.At developing of compounding of DCM the modifying additives: softeners, redispersion powders were applied. As the plasticizing additives the Kratasol, Hidetal P-4, S-3, SP-3, Melment^R F15G and Melflux^R 1641F were entered into a compounding. Additives of “Kratasol” series represent salts of naphthalenesulfoacids with the high maintenance of high-molecular fractions, an additive Hidetal of P-4 – hyper softener based on polikarboxylate.

Abstract: Additives addition into Mn-Ce/TiO₂ which had good low-temperature catalytic properties was studied, so as to improve its low-temperature anti-poisoning performance. Results showed that catalytic activity of Mn-Ce/TiO₂ added additives V, Fe and Cu (short for Mn-M-Ce/TiO₂ ) was improved all, compared with 95% NO conversion efficiency of Mn-Ce/TiO₂ at temperature of 120°C, the ratio of Mn-M-Ce/TiO₂ reached nearly 100%. Mn-Fe-Ce/TiO₂ had the best single anti-poisoning ability, under the existence of 7% vapor, its catalytic conversion efficiency could be always kept over 90% at 120°C.The anti-SO₂ poisoning ability at low-temperature reduced after adding additives Fe and Cu. catalytic conversion efficiency of Mn-Fe-Ce/TiO₂ and Mn-Cu-Ce/TiO₂ could be close to 90% at temperature of 180°C when water and SO₂ exist simultaneously.

Abstract: In this work, methods of introducing water-resistance to foamed gypsum were firstly adopted to investigate the influences of sulphoaluminate cement、redispersible latex powder and stearic acid emulsion on the mechanical strength、water absorption and softening coefficient. Scanning electron microscopy (SEM) was conducted to investigate microstructure of gypsum and phase composition of substances on plaster surface as well as the mechanisms. The result showed that sulphoaluminate cement reduced the water absorption of foamed gypsum, which decreases to 38.9% when dosage was 10%; Redispersible latex powder reduced the water absorption of foamed gypsum, which decreases to 35.6% when dosage was 5%; Stearic acid emulsion reduced the water absorption of foamed gypsum, which decreased to 30.1% when dosage was 3%; The combing use of sulphoaluminate cement、redispersible latex powder and stearic acid emulsion maked the water absorption decrease to 15.2% and the crystals became short and dense and a layer of organic hydrophobic membrane covered the surface of crystals and which makes gypsum less soluble and more suitable for use in humidity environment.

Abstract: Orthogonal testing method was used to study the effects of fly ash, aggregate, weight ratio of water and material, way of incorporation of hydrophobic agent, on dry density, compressive strength, water absorption and softening coefficient of composite insulation mortar. The optimal ratio was obtained as 15% of the total weight is fly ash, 40% of the weight are aggregate, weight ratio of water and material are 1.1, 0.2% is hydrophobic agent (hydrophobic agent was added in the mixture). The main performances of the mortar were recorded as dry density was 220Kg/m³, compressive strength after 28 days was 0.50MPa, and thermal conductivity 0.0593W/(m•K). Microstructure of the composite insulation mortar was analyzed by SEM (scanning electron microscopy) and its function mechanism was studied preliminarily.

Abstract: Orthogonal testing method was used to study the effects of polystyrene particles, hydrophobic agent, air-entraining agent, polypropylene monofilament fiber on dry density, compressive strength, water absorption and softening coefficient of composite insulation mortar. The optimal ratio was obtained as: 3% of the weight are polystyrene particles, 0.2% is hydrophobic agent, air-entraining agent counts for 0.4wt%，and polypropylene monofilament fiber 0.6%. The main performances of the mortar were recorded as: dry density was 228Kg/m3, 28 day compressive strength after conserved for 28 days was 0.54MPa, and thermal conductivity 0.0596W/(m•K). Microstructure of the composite insulation mortar was analyzed by SEM (scanning electron microscopy) and its function mechanism was studied preliminarily.

Abstract: A novel waterborne polyurethane (WPU) modified by tung oil was prepared with 2,4-tolylene diisocyanate, polyethylene glycol, dimethylol propinic acid, 1,4-butanedilo as main materials via acetone process. The structure of WPU molecule was characterized by FT-IR. Adhesive behavior for non-polar and/or low surface energy soft packing films was studied. Water resistance of films were evaluated by water contact angle and water uptake and thermal properties determined by thermal analysis instruments. The results show that the modified WPU films have good water and heat resistance. Both of modified WPUs or not have good adherence on BOPP films.