Mineral Wool Slabs Research Articles

How small-scale variation in mineral wool products effect random incidence sound absorption

Mineral wool products are produced by creating a spray of fibres, that is collected and made into slabs. This randomized spray can lead to small variations across a slab. Nevertheless, mineral wool slabs are often treated in acoustics as locally reacting perfectly homogeneous, isotropic materials. This means that small-scale characterisations are extrapolated to large-scale without considering the impact from possible variations in a large-scale setup. The question is how the small-scale characterisations should be used for large-scale setups with this in mind. Three products with the same thickness and density, but with significantly different specific airflow resistances were selected for random incidence sound absorption tests. The products were all specially made ceiling tiles and measurements were conducted in E200 setup according to ISO 354:2003. The tiles were gradually exchanged in a random fashion, so measurement results were obtained using a combination of tiles with different specific airflow resistances. Results showed a surprisingly linear relation between the sound absorption and the average specific airflow resistance of tiles used in the measurements. The results point to that variations in products must be observed, but also that small variations in specific airflow resistance in standardized products are insignificant.

Effects of supplemental lighting using HPS and LED lamps with different light spectra on growth and yield of the cucumber (Cucumis sativus L.) during winter cultivation in greenhouse

Abstract The aim of the experiment was to assess the effects of supplemental lighting of cucumber grown in greenhouse using lamps with differentiated light spectra: sodium lamps – high-pressure sodium (HPS) and light emitting diodes (LEDs). Plants (cucumber ‘Pacto’ F1) were grown in two greenhouse compartments with five light treatments: I – HPS + LED (top light with HPS LEDs as interlighting), II – only HPS as top light, III – LED R (LED chips on board (COB) type with an increased level of red band), IV – LED W (LED COB type, white), V – LED B (LED COB type with an increased level of blue spectrum). Light treatments: HPS + LEDs and HPS were grown in one greenhouse compartment and the other three light treatments: LED R (red light supplementation), LED W (without additional supplementation) and LED B (red spectrum supplementation) in the second compartment in analogous climatic conditions. The LED lamps using COB technology are known to be a very efficient source of light. Plants were cultivated from December 2018 to March 2019 in mineral wool slabs Grotop Master (100 × 15 × 10) with four plants on one mat. They were illuminated for 18 h (from 5 am to 11 pm), setting the threshold value (on and off) at 130 W. The plants were drip-irrigated with a complete nutrient solution. The irrigation was controlled based on a weighting system. The assessment of the effect of lighting on early yield and quality of cucumbers was completed after 8 weeks of cropping. It was shown that it was possible to obtain 3.59 kg from one plant during the 8-week period of evaluation by illuminating plants with sodium lamps (HPS), while using HPS and LEDs as additional illuminated inter-rows 3.89 kg. The yield of plants illuminated by LED lamps varied depending on the variant of the spectrum used and was respective for LED R, LED W and LED B, 3.30 kg, 3.90 kg and 3.25 kg. The obtained results indicated that the yield of cucumber ‘Pacto’ F1 grown with HPS lamps at top lighting and at the same time using interlighting with LED lamps was similar to LED W lamps (i.e. without additional supplementation in the range of red (LED R) and blue (LED B) light). Due to good results of LED lamps (type COB for top lighting or as interlighting) used for the cucumber supplemental lighting and high energy efficiency of LEDs, the promising future for that type of lamps compared with traditionally used HPS during winter cultivation in a greenhouse was demonstrated.

Исследование технологии возведения каркасно-панельных и модульных зданий в Арктике

Choosing the technology for the construction of buildings in the Arctic conditions is stipulated by two important factors, namely, the remoteness of the facilities and the short period of the summer season, which actualizes the problem of reducing the mass of structures and making shorter the construction work duration. In addition, one should keep in mind other important factors, such as permafrost, strong winds and low temperatures. Such conditions of construction necessitate the use of building technologies and space-planning solutions using light metal structures and mineral wool slabs, as well as sandwich-type laminated panels. The unified nomenclature, compactness and relative lightness of the parts ensure high efficiency of construction in the remote territories of the Arctic zone of the Russian Federation. The first experimental construction experience in the Arctic has shown not only the comfort of space-planning solutions, but also the manufacturability of installation of load-bearing and enclosing structures of the erected residential and administrative complexes of the Arctic Trefoil type. The block-modular technology for the construction of dormitory buildings in the village of Tiksi (Yakutia), as well as the technology for the construction of buildings of the production and logistics complex «Arkhangelsk», erected using light steel structures, sandwich type panels and other pre-fabricated structures. A comparison analysis of pre-fabricated building systems according to the criterion of manufacturability has been carried out. There are proposed some fundamental solutions aimed at improving the installation technology of buildings in the Arctic conditions.

Insulation systems for structures on pile supports

Construction on problem soils or in permafrost conditions involves using of pile foundations with a ventilated space under the floor structure. In this case, additional thermal insulation is required under the first-floor structure (above the ventilated space). The aim of research was to develop insulation systems for buildings on pile foundations for different climatic zones, including conditions of the arctic region and other regions with a predominance of ever-frozen ground. With the help of the THERM computer program, the conditions of bidimensional heat interchange in the enclosing structures of a building with pile foundation were simulated. The resulting models were analysed in terms of the thermophysical characteristics of the structures. As a result, the optimal version of the insulation system was chosen, effective both in the climatic conditions of the midland and in the especially cold conditions of Yakutia and Trans-Polar region (The Subarctic). This system included insulation with mineral wool slabs along the facade walls, with extruded foamed polystyrene along the basement part and the floor structure, and with rolled foamed polyethylene (with the formation of a seamless insulation shell) along the ventilated space under the floor structure and above, on top of insulation boards.

Insulation systems for structures on pile supports

Construction on problem soils or in permafrost conditions involves using of pile foundations with a ventilated space under the floor structure. In this case, additional thermal insulation is required under the first-floor structure (above the ventilated space). This problem is com-pounded by construction in cold regions. The goal of research was to develop insulation systems for buildings on pile foundations for different climatic zones, including conditions of the arctic region and other regions with a predominance of ever-frozen ground. With the help of the THERM computer program, the conditions of bidimensional heat interchange in the enclosing structures of a building with pile foundation were simulated. The construction of such buildings is practiced on problem soils. The resulting models were analyzed in terms of the thermophysical characteristics of the structures. As a result, the optimal version of the insulation system was chosen, effective both in the climatic conditions of the midland and in the especially cold conditions of Yakutia and Trans-Polar region (The Subarctic). This system included insulation with mineral wool slabs along the facade walls, with extruded polystyrene (XPS) foams along the basement part and the floor structure, and with roll polyethylene (PE) foams (with the formation of a seamless insulation shell) along the ventilated space under the floor structure and above, on top of insulation boards.

Water resistance of thermal insulation composites with cellulose-containing filler

One of the urgent tasks is the development of new thermal insulation materials to improve the energy efficiency of construction. In this work, new composites were obtained based on previously unused cellulose-containing waste. The theoretical and experimental substantiation of the possibility of increasing the water resistance of the heat-insulating composite has scientific significance. The features of the supramolecular structure of cellulose are analyzed. As a result of studies of the process of structure formation of a new heat-insulating material, it has been established that to ensure stable heat-insulating properties of composites from cellulose-containing waste, it is advisable to use a phenol-formaldehyde binder, water glass, or alumochromophosphate. The developed composite has a swelling 2.7 ... 3 times less, and water absorption 2.2 ... 2.4 times less than mineral wool slabs. The coefficient of thermal conductivity of the new composite material, depending on the type of cellulose-containing filler, ranges from 0.076 to 0.092 W/m∙K, which makes it possible to recommend it for use in thermal protection of buildings.

Optimization of technology of special-purpose mineral wool products

Insulation systems must have a number of special properties when used on construction sites located in the zone of significant negative temperatures, wind load, and associated air filtration through building struc-tures, under the influence of the coastal environment that forms salts on tech-nical facilities associated with the production and transportation of petro-leum products. Firstly, high operational stability, including under the influ-ence of aggressive environments. Secondly, they must be non-flammable and have significant fire resistance limits. Thirdly, do not contain compo-nents that are toxic during normal operation or are released in the event of a fire. The analysis of possibilities has shown that products based on stone wool meet these requirements to the greatest extent as a thermal insulation material. The research presented in the article is based on a hypothesis about the use of products based on stone wool and epoxy binder on latent hardeners, which will allow us to obtain an energy-efficient material that fully meets the conditions of polar construction. The purpose of the research was to develop a method for selecting the parameters of manufacturing mineral wool products that affect the properties of mineral wool slabs to the greatest extent and to opti-mize the temperature of heat treatment of mineral wool carpet. Re-search methodology set out in the article is based on the method of mathematical planning of experiment and statistical processing of the results, followed by analytical optimization.

Shear Failure of Sandwich Panels Subjected in Bending

The paper describes the behaviour of the sandwich panels in bending. Two panels of the same dimensions are tested. The panels differ only in the layout of the inner thermal insulation layer. The thermal insulation layer is made of separate mineral wool slabs. The graphs of the strain development in the external sheets, the displacement between the layers and mid-span displacement are presented in the paper. The nature of the failure shows that only separate internal thermal insulation slabs resist the shear force. Therefore, the complete width resistance cannot be evaluated. The views of the failure are also presented.

Safe usage of external enclosures under adverse environmental exposure

Introduction. The study considers the issue of safety of the human vital activity environment in the field of construction and usage of buildings, which includes, along with other types of safety, thermal, biological and mechanical safety. The last ones cannot be provided if there are inorganic hygroscopic salts in construction materials of external enclosures due to influence of the salts on the thermal, mechanical and other properties of the materials. Thermal conductivity coefficient of damped saline construction materials is determined on a developed experimental facility operating according to the principle of unsteady thermal conditions. A statistical analysis of the experimental results on thermal conductivity of materials possessing various structures and densities is carried out. Significance of the influence of the “salt content” factor on the thermal conductivity of saline materials in comparison with control non-saline samples is revealed. Materials and methods. Construction materials for the study are selected as follows: autoclave lime-and-sand brick and burnt brick with a density of 1800 kg/m3, autoclave foamed silicate with a density of 650 kg/m3, wood concrete with a density of 616 kg/m3 and mineral wool slabs with a density of 150 kg/m3. The generally accepted methods of laboratory research and statistical processing of experimental results are used. Laboratory methods include preparation, salinization with sodium chloride, potassium sulfate and calcium chloride, and measurements of the thermal conductivity coefficient of construction material samples. Results. The determination of thermal conductivity of wetted saline materials under unsteady thermal conditions makes it possible to eliminate drying of the samples and migration of salts and moisture. The presence of salt crystals increases the thermal conductivity of dry materials up to 80 % (rel.). Damping the samples promotes the dissolution of the crystals and lowering the thermal conductivity of the samples to values lower than those of non-saline samples with the same moisture content. Conclusions. The study proves the significance of the salinization effect on the thermal and physical characteristics of construction materials that must be taken into account when thermal engineering calculating external enclosures and predicting their moisture state during usage.

Optimization of insulation in ventilated hinged facade systems

The system of hinged ventilated facades is available for a long time and is now widely used in the construction of new and reconstruction of existing buildings for various purposes. As practice shows, the problems associated with the operation of these facade systems are usually caused by mistakes in the design, selection of components and installation of the system. Ventilated facade is a multi-layered enclosing structure, which includes a layer of insulation. Mineral wool slabs are ideal for this facade system, as it has low thermal conductivity, resistance to temperature changes and excellent vapor permeability, which allows to fully open the potential of a ventilated air layer. In the article two ways of installation of thermal insulation are considered: single-layer and two-layer with different types of air interlayer: closed, weakly and strongly ventilated. In accordance with the requirements of Russian and European regulatory documents, the effect of gaps between the thermal insulation plates in a single-layer and two-layer design on the reduction of the heat transfer resistance of hinged facade systems with an air gap was estimated by calculating 2-dimensional temperature fields. The coefficient of thermotechnic uniformity was also defined. As a result, optimal variants of thermal insulation and types of bases for fixing thermal insulation are suggested.

INVESTIGATION OF THE EFFICIENCY OF THE STEEL TUBE CONFINEMENT CONCRETE PILLARS PROTECTION BY FIRE-RETARDANT MATERIALS

Currently, in Ukraine and abroad for the construction of high-rise buildings and structures using pipe-like structures. Wide application of pipe concrete columns is due to their high carrying capacity at relatively smaller overall dimensions due to the blocking of cracking in concrete by a steel clasp. The advantages of concrete columns should include more simplified conditions of technology of manufacturing and installation on their basis of bearing structures of floor covering.
 Piping constructions consist of steel shells and concrete core. Since the steel pipe mainly provides the bearing capacity of the concrete column, its failure or reduction of stiffness, which is characteristic of the fire under the influence of its thermal factors, leads to destruction. Investigation of fire resistance of concrete structures, which are not protected by flame retardant coatings, showed that a steel clasp during a fire after 15 minutes is heated to a critical temperature of 500 ° C.The use of flame retardant coatings is an effective method of fire protection of concrete constructions, which prevents the rapid heating of steel welds and provides a normalized fire resistance limit for such structures. In this work, studies were carried out on the effectiveness of fire protection of concrete columns with different types of fire-retardant materials - mineral wool slabs, special flame retardants and flame-retardant coatings. For fire protection mineral wool materials were used ROCKWOOL plates of the series "Conlit SL150". Mineral wool plates "Conlit SL 150" consist of fibers of rocks of a basalt group, they can withstand, without melting, temperature more than 1000 ° С. The silica-based adhesive "Conlit Glue" can withstand temperatures above 900 ° C, has good adhesion when bonding Conlit SL 150 mineral wool slabs with protective structures. From the second type of fire-retardant materials, the fire-proof composition "Naktresk" was chosen on the basis of gypsum. The coating is formed in the process due to hardening of the mixture on protected surfaces. The third type of flame retardant materials is the flame-retardant intumessent coating "Pyro-Safe Flammoplast SP-A2".It has been established that with the use of fire protection systems on the basis of mineral wool plates "Conlit SL150" and fire retardant "Nutresc", the fire resistance class of reinforced concrete columns increases from R 15 to R 180. The fire protection system on the basis of the painted paint "Pyro-Safe Flammoplast SP-A2" »Increases fire resistance from R 15 to R 75

Relationship between chlorophyll fluorescence parameters and quality of the fresh and stored lettuce ( Lactuca sativa L.)

Abstract Quality of lettuce relates to growing conditions, cultivar and storage conditions. There is a need to introduce in the plant production a forecast system for abiotic stresses to enable recognizing early changes of the plant quality before visual changes occur, based on non-destructive measurement methods. The objective of this study was to evaluate the relationship between photochemical processes dynamics and quality parameters of the lettuce. The results will be useful to assess the quality and storage ability of the lettuce and to determine chlorophyll fluorescence parameters, which could well characterize early changes of quality during plant production and storage. Two cultivars of lettuce were investigated 'Omega' F1 - butterhead lettuce type, and 'Aficion' F1 - 'Batavia' type, which were grown in three hydroponic systems: in mineral wool slabs, coconut fibre, and NFT (nutrient film technique). The harvested plants were tested after 3 d and after 6 d of storage. The results of this study showed that lettuce of 'Aficion' F1 and 'Omega' F1 cvs. differ significantly in yield, quality and different ChlF parameters. 'Aficion' F1 of 'Batavia' type was characterized by higher dry mass, soluble solids, Chl a, Chl b and carotenoid contents than the 'Omega' F1 plants. Only 'Omega' cultivar showed reaction to the growing medium used. The influence of storage period on both cultivars was similar. Storage for 3 d period particularly affected decreasing of SPAD index, and the chlorophyll fluorescence parameters such as PI total, Area, Fo, Fm, Fv, Reo / CSo and increasing of ABS / RC, kP / ABS × kF and kN / ABS × kF. In general, 'Aficion' plants photosynthetic apparatus was significantly less modified during the storage. The level of degradation of the plant tissues during storage has a different effect on structure and reactions in photosynthetic light phase parameters in leaves. The analysis of the photoinduced chlorophyll fluorescence rise allows to monitor the damage dynamics in thylakoid membranes and connect them with the quality parameters of plant tissue.

Mineral Wool Macrostructure Parameter’s Relation with Product’s Mechanical Properties

The experimental tests established the relations of rigid mineral wool products (with different structure) macrostructure parameters with main their mechanical characteristic – compressibility. The products within the nominal density between 45 and 170 kg/m3 were analysed. Determined that strong functional relationship exists between the values of critical compressive stress and macrostructure parameters, density and organic content of mineral wool products, because the value of the multiple correlation coefficient equals 0.95. Using the obtained empirical equation is possible predict and calculate the mechanical behiaviour (compression stress) of mineral wool slabs by using macrostructure parameters and other (density, organic content) characteristics.

An estimated prediction of the deformability of mineral wool (MW) slabs under long-term compressive stress

This paper presents the results of testing the strength and deformability of mineral wool slabs used for insulating flat roofs, facades, cast-in-place floors and external basement walls as well as for sound insulation in the floor slabs of buildings. The empirical equations for calculating the stress σ10%, tangential modulus of elasticity E and ultimate relative strain ɛcr (which, when exceeded, causes a considerable strain increase) of mineral wool slabs under short-term compression are provided. A regression model of the interrelationship between the predicted pointwise values of creep strains for a lead time of 10years and parameters such as the density, long-term compressive stress σc=0.35·σ10% and ultimate relative strain ɛcr of slabs under short-term compression is suggested.

Effect of Growing Medium and Harvest Term on Yield and Several Quality Traits of Two Cultivars of ‘‘Cherry’’ Tomatoes

The objective of the study was to determine the effect of growing medium in greenhouse cultivation on the yield and fruits quality of “cherry” tomato two cultivars. Cultivars ‘Dasher F1’ and ‘Pareso F1’ were chosen for the experiment. The growing mediums compared were: standard mineral wool slabs and coconut fibre slabs, chosen as an environmentally friendly alternative to mineral wool. Tomato seeds were sown in December; seedlings were planted to the experimental greenhouse in January. The fruits were harvested at 5th stage of maturity, according to USDA classification (i.e. ‘light-red’), and subjected to analyses. Harvest terms for quality evaluation of the fruits were June and September. There were determined for the fruits: total and marketable yield, and quality parameters: pH of the fruit juice, titratable acidity, total sugars, soluble solids, total phenolic acids, lycopene, α-carotene and β-carotene contents. The results showed that the fruits harvested in September showed a higher dry matter and carotenoid content that the fruits harvested in June. However, the fruits harvested in June were characterized by a higher total sugars content, higher pH of the juice and higher soluble solids content. The plants grown in both mediums had fruits of similar quality, but the plants grown in coconut fibre showed noticeably higher total yield. Therefore, it can be concluded that the coconut fibre can be used as the environmentally friendly medium for greenhouse cultivation of ‘cherry’ tomatoes, the alternative to mineral wool.

Analysis of Structure and Deformation Mechanisms of Mineral Wool Slabs under Compression

The products of mineral wool are widely used for thermal insulation of buildings, both at construction of new buildings and at renovation of old ones. The mechanical resistance and stability of them, as well as their energy saving and heat saving requirements are in most cases related to the essential specifications of the building. The mechanical characteristics of these products are subject to structure of material, density, content of binder in the product and to technology of production. Subject to the latter, mineral wool products with different fibrous structure are received, therefore, for the structure of each type, the individual structural models are developed attempting to describe the properties of fibrous systems. The deformability of mineral wool products is conditioned by mobility of fibrous structure, which shows up best under compression by short term loads. This study established the impact of various thicknesses and deformations on changes in structure of rock wool products. It also established that the thickness of mineral wool products conditions and influences considerable changes in their structure. DOI: http://dx.doi.org/10.5755/j01.ms.18.2.1926

Long-term prediction of creep strains of mineral wool slabs under constant compressive stress

The results obtained in determining the creep strain of mineral wool slabs under compressive stress, used for insulating flat roofs and facades, cast-in-place floors, curtain and external basement walls, as well as for sound insulation of floors, are presented. The creep strain tests were conducted under a compressive stress of σ c =0.35σ 10%. Interval forecasting of creep strain was made by extrapolating the creep behaviour and approximated in accordance with EN 1606 by a power equation and reduced to a linear form using logarithms. This was performed for a lead time of 10 years. The extension of the range of the confidence interval due to discount of the prediction data, i.e. a decrease in their informativity was allowed for by an additional coefficient. Analysis of the experimental data obtained from the tests having 65 and 122 days duration showed that the prediction of creep strains for 10 years can be made based on data obtained in experiments with durations shorter than the 122 days as specified by EN 13162. Interval prediction of creep strains (with a confidence probability of 90%) was based on using the mean square deviation of the actual direct observations of creep strains in logarithmic form to have the linear trend in a retrospective area.

Strength and deformability of mineral wool slabs under short-term compressive, tensile and shear loads

The results obtained in the experimental study of mineral wool slabs under short-term compressive, tensile and shear loads, used for insulating flat roofs, cast-in-place floors, curtain and external basement walls, as well as for sound insulation of floors, are presented. To describe the experimental data of strength and deformability of mineral wool slabs, the regression equations of the linear form, provided with one-sided confidence intervals for predicting the resultant characteristic with probability Р = 0.90, are used. The interrelationship between strength and deformability characteristics of mineral wool slabs under tension and shear, and their strength and deformability under short-term compression are determined. Based on the experimental data, differences in deformability and strength characteristics of mineral wool slabs under shear load in mutually perpendicular planes (in the direction of slab forming and perpendicular to it) are demonstrated.

Strength and Deformability of Mineral Wool Slabs Under Short – Term Cyclic Compression

The strength and deformability of mineral wools slabs, as well as thermo-insulating characteristics can be attributed to the most important indices determining the popularity of these products in practice. The mechanical resistance and stability of mineral wool slabs in use (at construction) of buildings, as well as the requirements for energy saving and heat conservation are in most cases related to the essential requirements set for a building. The mechanical characteristics of mineral wool slabs are subject to structure, density of material, percentage of binder in product, as well as production techniques. The deformability of mineral wools slabs is determined by mobility of fibrous structure, which is best observed under compression by short-term loads. The article considers the strength and deformability properties of mineral wool products under compression by short-term cyclic load. The results obtained while investigating the compression of mineral wool slabs can be applied for determination of fields and conditions for use of such products in constructions of buildings (floors, ceilings, roofs), as well as for substantiation of respective technical requirements in the normative documents for design of these constructions.

The impact of the exterior painted thin-layer render’s water vapour and liquid water permeability on the moisture state of the wall insulating system

The paper aims at the determination of the possible limits of vapour resistance and liquid water permeability alteration in the case of the exterior painted thin-layer render finish of the building walls from outside insulated with the mineral wool slabs when exploited in the area of cold and humid climate that could guarantee a normal moisture state of the wall insulating system. The moisture testing of the insulating system’s fragments was carried out in the climatic chamber, where the climatic parameters were modelled on the basis of the climatic typical of Lithuania. Thin-layer render was coated with acrylic paints. When the thickness of the paint coating on thin-layer render was increased from 0.08 mm to 0.24 mm, the liquid water absorption coefficient decreased by 59% and vapour resistance increased by 43%. It has also been determined that in the double-layer system paint coating – thin-layer render condensation moisture will be accumulated when the thickness of the air layer s d equivalent to the material’s water vapour permeability is higher than 0.6 m. Rain will have an impact on the wall’s moisture state, when the liquid water absorption coefficient w of the double-layer system paint coating – thin-layer render is higher than 0.025 kg/(m 2 h 0.5). The micro-lens discovered in the areas of moisture accumulation by the thermographic analysis should be considered as the rudiments of the defect formation in the exterior insulating system.