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Directions of possible compressive load working: allegedly perpendicular (1); allegedly parallel (2); allegedly tangential (3) Marking of the load working direction was chosen according to the wool layer movement on the conveyor (by production line direction) and visible conveyor belt pattern on the product surface. The average of the 5 results obtained during the research is illustrated in Fig 8.
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This paper presents the research on the structure and compressive stress or compressive strength of mineral wool products. The products of chaotic, directional and combinative fibres structure have been studied visually and micro-scopically. During mechanical tests it was determined that compressive stress (compressive strength) of the stone wool p...
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This paper presents the results of a study on the use of ground calcined-clay brick residuals, produced by the ceramic industry, as a supplementary pozzuolanic cementing material for use in concrete. The ceramic residue was characterized by physical, chemical and mineralogical tests. The feasibility of the substitution of the cement by the ceramic...
This paper presents the research on the structure and compressive stress or compressive strength of mineral wool products. The products of chaotic, directional and combinative fibres structure have been studied visually and microscopically. During mechanical tests it was determined that compressive stress (compressive strength) of the stone wool pr...
The research concerns the feasibility of recycling fibers from mineral wool residues from construction and demolition waste, by incorporating them into a fine grained concrete. All the specimens of concrete with various types of fibers have been subjected to the mechanical tests of flexural and compressive strength. Also the pre-cracking and postcr...
Citations
... The values of modulus, strength and toughness determined after the compression tests are reported in Table 1. All samples showed mechanical properties that were superior to those of polymer foams (EPS and PU) [51][52][53][54] and outperformed by far those of mineral-based insulation materials (glass wool and mineral wool) [55], which will make them particularly suitable for load-bearing applications. The compressive modulus ( Figure 6 and Figure 7) increased from 30 to 45 min of sintering time, while it remained unchanged after increasing the sintering time from 45 to 90 min. ...
The production of glass foams obtained by recycling post-consumer glass and textile industry processing waste is presented. The mechanical, thermal and acoustic properties were characterized as a function of process temperature and time. The results showed that it is possible to produce glass foams with thermal and acoustic insulation properties from a mixture consisting of 96.5% of glass waste, 1% of textile waste and 2.5% of manganese dioxide, processed at temperatures between 800 and 900 °C for a time between 30 and 90 min. The samples had density in the range of 200–300 kg m−3, porosity of 87–92%, thermal conductivity of 85–105 mW m−1 K−1, noise-reducing factors of 0.15–0.40 and compressive strength of 1.2–3.0 MPa. Although their insulation performance was not as outstanding as that of polymer foams, these materials can emerge as competitive candidates for applications requiring non-flammability and high-temperature load bearing capacity in combination with low weight, mechanical strength, and thermal and acoustic insulation properties. The use of secondary raw materials (which accounted for 97.5% by weight of the synthetic blend) limits the energy required compared to that needed for the extraction, transportation and processing of primary raw materials, making these foams attractive also in terms of environmental footprint.
... (A. Buska) complications [4, 8]. The research [9] showed that mechanical deformation of resilient materials has different influence on its compressive strength. ...
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/m(3) 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.
... The most important strenght indicators of thermal insulation materials are: compression stress by 10% deformation , stress parallel to the sample surface and com- pressibility [4]. For compression research there were 3 samples with different amount of the binder and different granulometry prepared. ...
In this article the thermodynamical and mechanical research of organic thermal insulation slabs prepared from cardboard refuse and synthetical binding material is presented. For this aim the samples with different amount of binding material, different density and different thermal insulation material granulometry were used. During the research it was established that granulometric composition of thermal insulation material and amount of the binder influence density of the samples. In all cases density influences the alternation of thermal conduction coefficient. The lowest thermal conduction have the samples prepared from milled cardboard, bolted through 1.5 mm bolter. During the research of mechanical characteristics it was determined that the best strength characteristics have the samples prepared with bigger amount of the binder and higher density.
... The use of these boards allow to reduce the time, cost and amount of works, when insulating flat roofs. Dual density single ply thermal insulating boards are used instead of two-ply joint overlaying thermal insulation layer (Buska and Mačiulaitis 2007). Due to deviation of dual density single-ply board measurements, vertical air gaps may form at the joints of it. ...
In order to reduce the amounts of work at the construction site, single‐ply dual density thermal insulating roofing boards are used with increasing frequency for thermal insulation of flat roofs. In this case, the joints between boards are not overlapped by the other ply over it; therefore gaps of varying width form between the sides of the boards through the entire thickness of the insulating layer, whose effect on the effective thermal conductivity of the thermal insulating layer must be evaluated. The aim of this project was to assess the reliability of standard method, used to determine the impact of such air gaps on the effective thermal conductivity of the thermal insulating layer by comparing the results of calculations and the results of measurements of thermal conductivity, also to determine the correction factors for thermal transmittance of horizontal thermal insulation layers due to the forming vertical air gaps between the single‐ply mineral wool boards. After measurements of thermal resistances of 50 mm thick thermal insulation board with the air gaps which width varied from 3 mm to 20 mm, it was determined that the thermal conductivity value of the air gaps increases with the increment of the width of air gaps. After completion the experimental measurements of thermal conductivity it was determined that the height of closed and unventilated or partly ventilated air gaps has no effect on the properties of effective thermal conductivity of the thermal insulation layer when the air gap width is up to 5 mm. When wider unventilated or partly ventilated air gaps occur, the effective thermal conductivity coefficient increases proportionally as the height of the air gaps increases. Calculated according to the standard method the affix to the thermal transmittance is overly general and not always appropriate. In some cases it is 6 times higher or 4 times lower than the measured one. In this paper a method to evaluate the effects of air gaps by the use of correction factor to the thermal transmittance of the horizontal thermal insulating layer is proposed.
In the construction sector, the search for sustainable, environmentally friendly, and economical materials continues to find alternatives to conventional thermal insulation materials. Magnesium oxychloride cement (MOC) is widely used in panels, industrial floor coverings, and exterior wall coverings because of some of its properties some of its advantages high strength, fire resistance, and abrasion resistance. In this study, it is aimed to produce an ultra-lightweight composite (L·MOC) with the apparent density of ≤ 150 kg·m⁻³, compressive strength of ≥ 150 kPa, and thermal conductivity of ≤ 0.05 W·(mK)⁻¹ by using of MOC. For the L·MOC samples obtained within the scope of the study, the effects of mixing ratios on the physical, thermal, and mechanical properties of the material were investigated in detail. The basic raw materials used in the study were MgO, MgCl2·6H2O, and water. In addition, hydrogen peroxide was used as a blowing agent, potassium iodide as a catalyst, and carboxy methylcellulose as a thickener. The demolded samples were cured for 28 days under 23 °C and 50 % relative humidity conditions. The apparent density, compressive strength, and thermal conductivity tests of the hardened specimens were performed, and hydration products and microstructure analyses were performed. Afterward, the experimental results were evaluated to investigate the effects of mixing ratios on the physical, mechanical, and thermal properties the composite samples. Thus, the optimum ratios of hydrogen peroxide, cellulose, potassium iodide, and water were determined. As a result, the production of LMOC composite with an apparent density of 101 kg·m⁻³, compressive strength of ~ 200 kPa, and thermal conductivity of 0.048 W·(mK)⁻¹ was achieved.
Graphical Abstract
Vilniaus Gedimino technikos universitetas El. paštas: lais@termo.vgtu.lt Santrauka. Pastato ir jo atitvarin konstrukcijos turi būti pakankamai patikimos ir ekonomiškos. Konstrukcijos patikimu-mas priklauso nuo naudotų medžiagų savybių ir veikiančių įvairių apkrovų derinio, o ekonomiškumas-nuo medžiagų kainos, ilgaamžiškumo ir termoizoliacinių savybių. Šiuo metu termoizoliaciniam sluoksniui naudojama nemažai akmens vatos gami-nių, kurie skirti apšiltinti sienas, grindis, stogus bei kaip grindų garso izoliacija. Akmens vatos gaminių naudojamų pastatų eksploatacijoje (statyboje), mechaninis atsparumas ir pastovumas bei energijos taupymo ir šilumos išsaugojimo reikalavimai daugeliu atveju siejami su esminiais statinio reikalavimais. Parenkant tinkamus gaminius, reikia įvertinti ir d montavimo bei eksploatacijos metu atsirandančias apkrovas (pvz. plokščiuose stoguose vaikščiojimo, medžiagų svorio, sumontuotų įren-ginių svorio ir kt). Šiame straipsnyje pateikiami ilgalaikkmis pastoviomis gniuždančiomis apkrovomis veikiamų akmens va-tos plokščių deformatyvumo tyrimų rezultatai gauti esant pastoviam gniuždymo įtempiui (σ c = 0,35σ 10%). Tyrimų rezultatai gauti naudojant akmens vatos plokštes, kurių tankis 95 kg/m 3 . Eksperimento metu išbandytos 6 bandinių serijos po 5 bandi-nius, gniuždant juos ilgalaike pastovia apkrova 122 paras. Tyrimų rezultatai apdoroti remiantis laipsnine lygtimi pagal LST EN 1606 standartą bei eksponentine lytimi. Nustatyta, kad tiek laipsnine, tiek eksponentine regresin lygtimis aproksi-muotos valkšnumo kreivvs vienodai gerai atitinka eksperimentinius duomenis. Reikšminiai žodžiai: akmens vatos plokšt ilgalaikks apkrovos, deformacija, valkšnumas. Įvadas Pagrindiniai šiuo metu naudojami energiniai ištekliai – tai gamtiniai ištekliai, kurie yra riboti, o jų gavyba nuolat brangsta. Besaikio energijos naudojimo mastas trikdo globalinę ekologinę pusiausvyrą. Apie 40 % šilumin energijos sunaudojama pastatams šildyti, nes anksčiau, statant gyvenamuosius namus ir kitos paskirties pastatus, apie kuro ir energijos taupymą ddl žemos jų kainos galvo-jama buvo mažai, tad tie pastatai visai nebuvo šiltinti arba šiltinti menkai (Buska 2010). Energijos taupymui ir jos vartojimo efektyvumui didinti imta peržiūrin pastatų ir statinių statybos bei eksploatavimo norminius dokumen-tus, siekiant pagerinti termoizoliacines pastatų atitvarų savybes, didinant efektyvių termoizoliacinių medžiagų naudojimo apimtis mažinant energijos sąnaudas (Buska 2010; Buska, Mačiulaitis 2007). Vienos efektyviausių termoizoliacinių medžiagų yra akmens vatos gaminiai, kurie plačiai naudojami pastatų ir statinių atitvarin konstrukcijose ddl mažo šilumos lai-dumo, gerų priešgaisrinių ir garso izoliacinių savybių, gausios žaliavų baz plataus dirbinių taikymo masto ir kt. Struktūriškai akmens vata apibūdinama kaip erdvin sistema, sudaryta iš daugybbs tam tikra tvarka išsiddsčiu-sių vienas kito atžvilgiu ir susipynusių plaušų, tarpusavyje (dažniausiai plaušų kontaktų vietose) sujungtų rišikliu. Mokslininkas (Blagojević et al. 2004) teigia, kad paga-minto produkto kokybb priklauso nuo plaušų struktūros ir neišplaušintų dalelių kiekio vatoje (1 pav.). O plaušai vertinami pagal jų storį (skersmenį) ir ilgį bei atitinkamą jų santykio svyravimą (Buska 2010).
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.
This paper provides with the experimental results obtained by determination the dependence of the compressive stress at the 10 % deformation of the layered-structure dual-density mineral wool slabs (or their parts) on their density, also the influence of the density of separate layers on the compressive stress of the whole product and different density layers of the dual-density structure mineral wool. The test results show that, while applying to the layered-structure dual-density specimen by the compressive load, firstly, the lower-density slab part (layer) deforms, and, after it reaches a certain limit of consistence, the higher-density layer slightly deforms, as well. The values of the compressive stress of the layered- structure dual-density stone wool slabs depend on the density, and the values of the compressive stress of the whole product depend more on the density of the layer having the lower-density and its compressive stress.
Geopolymerization is an emerging technology which utilizes solid aluminosilicate raw materials that are easily soluble in caustic solutions, in order to produce inorganic polymers with excellent physical, mechanical and thermal properties. In this paper is demonstrated the ability of geopolymerization technology for production of thermal insulating foamy inorganic polymers utilizing as solid raw material ultrafine perlite which is a by-product from comminution and sizing operations of perlite exploitation. Hydrogen peroxide is used as a chemical blowing agent for the foaming of inorganic polymers. The effect of addition of the blowing agent on the thermophysical properties of thermal insulating materials is demonstrated and these properties are compared with the ones of the commercial thermal insulating materials indicating the high potentiality for the development of this new family of inorganic polymeric materials.Research highlights► Development of a new family of thermal insulating foamy inorganic polymers. ► Comparable thermal conductivity values with the common insulating organic and inorganic materials. ► Superior thermal properties such as maximum application temperature and fire resistance. ► Superior mechanical properties.
The results of investigating the creep strain mineral wool slabs used for thermal insulation of flat roofs, cast-in-place floors and external walls of basements subjected to long-term compressive stress σc=0.35σ10% are presented. Slabs under short-term compressive stress are tested and regressive equations for calculating the stress σ10%, ultimate stress σcr, which slabs can endure without changing their structure, and the respective relative ultimate strain εcr, as well as the initial modulus of elasticity E, are offered. For the approximation of the creep curves an exponential equation is used according to EN 1606. It has been shown that the prediction of the creep strains for the lead time of 10 years may be made based on the data obtained in the direct experiment with the duration shorter than 122 days as specified in EN13162. A possibility of estimating the expected creep strains of mineral wool slabs for the lead time of 10 years, based on the stress σc=0.35σ10% and relative ultimate strain εcr of slabs under short-term compressive stress, has been considered.
