The article discusses the effect of additives of waste mineral wool fibers on geopolymer binder. This is an important study in terms of the possibility of recycling mineral wool waste. The paper ...describes an effective method for pulverizing the wool and the methodology for forming geopolymer samples, labeled G1 for glass-wool-based geopolymer and G2 for stone-wool-based geopolymer. The compressive and flexural strengths and thermal conductivity coefficient of the geopolymer with the addition of mineral fibers were determined. The key element of the article is to verify whether the addition of mineral wool fibers positively affects the properties of the geopolymer. The results obtained prove that the addition of fibers significantly improves the flexural strength. For the G1 formulation, the ratio of compressive strength to flexural strength is 18.7%. However, for G2 samples, an even better ratio of compressive strength to flexural strength values of 26.3% was obtained. The average thermal conductivity coefficient obtained was 1.053 W/(m·K) for the G1 series samples and 0.953 W/(m·K) for the G2 series samples. The conclusions obtained show a correlation between the porosity and compressive strength and thermal conductivity coefficient. The higher the porosity, the better the thermal insulation of the material and the weaker the compressive strength.
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•B2O3 substitution for SiO2 in ferronickel slag decreased its melting temperature.•Crystallization of ferronickel slag was also weakened after replacing SiO2 by B2O3.•So, replacing ...SiO2 by B2O3 in the slag is beneficial for mineral wool production.
Utilization of ferronickel slag as a raw material for mineral wool production not only conserves natural resources, but also achieves the sustainable development for the ferronickel industry. In order to utilize the ferronickel slag more efficiently, the melting and crystallization behaviors of the slag with the partial replacement of SiO2 by B2O3 were investigated in this paper. The results show that the initial and complete melting temperatures decreased with B2O3 substitution for SiO2, which indicates that the addition of B2O3 can reduce the energy consumption during the melting process. The incubation time of the slag in the Time Temperature Transformation (TTT) diagram increased, whereas the initial crystallization temperature in the Continuous Cooling Transformation (CCT) diagram decreased when SiO2 was substituted by B2O3. In addition, the main crystalline phases precipitated in the slags were columnar MgSiO3 and Mg2SiO4. The weakening of crystallization ability caused by the substitution of B2O3 for SiO2 will be beneficial for the improvement of fiber quality when the ferronickel slag is used as a raw material for mineral wool production.
A literature study was carried out with respect to the release and accumulation of formaldehyde indoors. With reference to representative emission data, exposure scenarios were calculated on the ...basis of the European Reference Room with the aid of Monte-Carlo methods. Furthermore, data concerning formaldehyde concentrations in indoor and outdoor air, as well as data on air exchange, were collected for the European region. Various permanent, intermitting and temporary emission sources were compared under the specified conditions of the Reference Room. It was thereby necessary to bear in mind that, for example, the emission tests for raw wood-based materials and mineral wool do not take place under realistic conditions, as these products are not applied open in indoor areas. It is demonstrated that coatings and coverings drastically reduce the release of formaldehyde into the room air. Moreover, it becomes clear that the Reference Room concept allows a comparison of emission sources but also greatly overestimates the formaldehyde concentrations in indoor areas when diverse sources are simply added together. In view of the discussed aspects, as well as taking into account outdoor air conditions and diverse secondary sources, the potential problem of exposure to high formaldehyde concentrations in indoor areas can therefore not be solved through the further tightening of already existing regulations, in particular because peak concentrations and therefore high exposures would remain largely uninfluenced. Due to the fact that formaldehyde is a compound with a threshold effect, this aspect is of considerable importance. Consequently, an appropriate risk management option would be to primarily address the peak concentrations originating from temporary and intermitting sources.
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•Air exchange rates under living conditions in European housings are investigated.•Formaldehyde sources and concentrations in European housings are evaluated.•Permanent, intermitting and temporary formaldehyde sources are identified.•Formaldehyde sources are directly compared by conversion into Reference Room concentrations.•Formaldehyde emission scenarios are calculated under consideration of sink effects and aging.
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•The environmental analysis of different insulation materials is presented.•The operational phase is the most critical stage during the whole life cycle.•The considered mineral wool ...showed the best environmental impact.•The studied PU, MW, XPS showed an encouraging environmental payback.
The construction industry is one of the less sustainable activities on the planet, constituting 40% of the total energy demand and approximately 44% of the total material use and the generation of 40–50% of the global output of greenhouse gases. The biggest environmental impact caused by buildings is generated during their operational phase due to the energy consumption for thermal conditioning. Hence, in order to reduce this energy consumption, insulation materials must be used and from a life-cycle perspective, the use of insulation materials reduces the building impact over time. This paper develops a comparative life cycle assessment (LCA) of different insulation materials (polyurethane, extruded polystyrene, and mineral wool) to analyse the environmental profile of each insulation material type in the Mediterranean continental climate. Significantly, all three insulation materials demonstrated a net positive benefit over a fifty-year life span due to the reduced heating requirements of the building. Results showed that the highest environmental impact was associated with the polystyrene insulation material and the best environmental performance was for the mineral wool. Moreover, regarding the consumption, polyurethane and mineral wool had similar thermal performance during the whole year. Furthermore, the environmental payback period shows that the cubicles with insulation material are environmentally efficient, if they are used for at least 7 years (for mineral wool), 10 years (polyurethane), and 12 years (extruded polystyrene). The results of this research give new insights into the effect on building insulation materials.
Globally, as human population and industries grow, so does the creation of agricultural, industrial, and demolition waste. When these wastes are not properly recycled, reused, or disposed of, they ...pose a threat to the environment. The importance of this study lies in the beneficial use of coconut fibre and mineral wool in the form of fibres in cement mortar production. This study examines the use of coconut and mineral wool fibres in the production of fibre-reinforced mortar. Five different mortar mixtures were prepared, having one control mortar along with four fibre-reinforced mortars. The control mortar is denoted as CM while 1% and 1.5% of mineral wool are incorporated into this mortar mix and denoted as RMM-1.0 and RMM-1.5, respectively. Additionally, the mortar sample configurations contain 1% and 1.5% coconut fibers, designated as RCM-1.0 and RCM-1.5. These samples were subjected to different strength and durability tests to determine their suitability for use in mortar production. The testing findings show that mortar containing 1.5% mineral wool has better compared flexural strength and durability properties. The investigation results will form part of the database for the efficient utilization of natural and waste fibres in the construction and building sectors.
Building insulation is an essential requirement for buildings located in areas of varying temperature conditions. However, the conventional building insulation techniques accrue high cost and consume ...resources. This work aimed to evaluate the use of mineral wool and rice straw to improve Portland cement mortar's thermal insulating properties. Samples of 40x40x160 mm mortar were produced with cement and sand, but varying mineral wool and rice straw constituents from 0 to 50% in weight. Water absorption, flexural and compressive strengths, thermal conductivity were performed in samples with and without mineral wool and rice straw addition. The microstructure of mortars was analyzed using scanning electron microscopy (SEM). It was observed that reinforcing mortars with mineral wool and rice straw fibers yielded a significant drop in the mortar's thermal conductivity, improving their insulative abilities. Although the addition of fibers, in turn, deferred the mechanical performance in some mixes, however, it was not too significant or below workable standards. The performed tests prove the feasibility of adopting the selected fibers for insulating Portland cement mortars.
•Mineral wool and rice straw as thermal insulation enhancer.•Thermal conductivity of mortar reduced with fiber additions.•Rice straw and mineral improved mechanical properties of mortars.
Mineral waste wool represents a significant part of construction and demolition waste (CDW) not yet being successfully re-utilized. In the present study, waste stone wool (SW) and glass wool (GW) in ...the form received, without removing the binder, were evaluated for their potential use in alkali activation technology. It was confirmed that both can be used in the preparation of alkali-activated materials (AAMs), whether cured at room temperature or at an elevated temperature in order to speed up the reaction. The results show that it is possible to obtain a compressive strength of over 50 MPa using SW or GW as a precursor. A strength of 53 MPa was obtained in AAM based on GW after curing for 3 days at 40 °C, while a similar compressive strength (58 MPa) was achieved after curing the GW mixture for 56 days at room temperature. In general, the mechanical properties of samples based on GW are better than those based on SW. The evolution of mechanical properties and recognition of influential parameters were determined by various microstructural analyses, including XRD, SEM, MIP, and FTIR. The type of activator (solely NaOH or a combination of NaOH and sodium silicate), and the SiO2/Na2O and liquid to solid (L/S) ratios were found to be the significant parameters. A lower SiO2/Na2O ratio and low L/S ratio significantly improve the mechanical strength of AAMs made from both types of mineral wool.
Abstract
Fibrous insulations are susceptible to air filtration, which affects both heat loss and moisture transport in the materials. Each fibrous material has individual heat and mass transfer ...characteristics. This is due to the structure of the fibers, their connections, and their density. The authors performed tests of the air permeability of loose mineral wool and wood wool of different densities and moisture content levels. We are presenting a comparison of materials, and their transport characteristics depending on density and moisture content. Convective moisture flow caused by air filtration is different for mineral and wood wool. The difference in the form of accumulation of sorption moisture in the material affects its redistribution due to the flow of air.
•Waste mineral fibres are an alternative to the reinforcement fibres used nowadays.•After the test mortars reinforced with mineral fiber waste improve thermal properties.•It is possible to replace ...large amount of the volume of sand used by mineral fiber waste.•Mortars with fibre residues after the fire test maintain its mechanical properties.
The objective of this research is to analyse the fire resistance of cement mortars with mineral wool from construction and demolition waste (CDW) recycling. The recycled mortars are therefore exposed to direct fire reaching a maximum temperature of 700 °C, and an experimental plan is designed to analyse thermo-mechanical behaviour before and after the testing of the mortars with different types of recycled fibres. The results show that the surface hardness of all mortars is practically unchanged after the fire, whereas the incorporation of fibre residues produce a significant improvement in the flexural strength after fire test compared with the reference mortar. The compressive strength values of all mortars decrease after the fire although they remain at optimum values for use according to regulatory requirements. The values of thermal conductivity are lower or remain unchanged after the fire test. Results show that the addition of these recycled fibres can be a sustainable alternative to the commercial ones currently being used, improving mechanical-thermal behaviour after the fire and preventing the explosive behaviour of the mortars.
This study investigates the coupling effect of mechanically activated nepheline-syenite (NS) and mineral wool melt waste (MWMW) on the physical-mechanical properties of a ceramic body. The results ...indicate that an optimal amount (10-20%) of NS additive promotes the formation of the smallest pore size from 0.001 to 0.01 µm, as well as improves physical, mechanical, and durability properties of the ceramic samples with MWMW, when fired at temperatures between 1000 and 1080 °C. As the NS content increases, the composition becomes more alkaline, leading to enhanced vitrification and the formation of a glass phase during firing. This reduces open porosity, modifies pore size distribution, and enhances compressive strength and frost resistance. An NS content of 15% produces the best results, increasing the smallest pore fraction and yielding favourable properties, such as reduced open porosity, water absorption and density, increased compressive strength, and does not affect the linear shrinkage. The frost resistance test demonstrates that the coupling effect of NS additive and MWMW improves the samples' resistance to freeze-thaw cycles, with the best performance observed at 15% NS content. The study also highlights the usefulness of structural parameters and ultrasound testing for assessing and predicting the frost resistance of ceramic samples.
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