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The possibility of using the waste from the production of mineral wool (MW) and nepheline-syenite (NS) in the production of ceramics in order to improve the physical and mechanical properties as well as the frost resistance of the samples was investigated. The use of NS in amounts 5 – 15% increases the compression strength of the samples to 17% and reduces the density, water absorption, and ultrasound speed in the samples to 5.2, 12.5 and 7% after firing at 1060°C. An increase in the NS amount due to an increase in the number of pores with diameters 0.02 – 0.1 μm in the samples promotes diminishes the damage to samples during freezing– thawing processes.

The combined use of waste from the production of mineral wool (MW) and spent catalyst (SC) from catalytic cracking of petroleum products in the production of ceramics was investigated. It was found that, compared with the control composition, in the firing process at temperature 1080°C the MW acts as a fluxing additive, increasing the density of the samples by 3.3%, strength in compression by 19.2%, and shrinkage deformation by 16.1% and reducing water absorption by a factor of 3. The combined use ofMWand SC in the composition (SC increasing from 10 to 20%) contributes to the intensification of the crystallization of the minerals anorthite and mullite, which contributes to shrinkage deformation reduction by up to a factor of 1.85 without degradation of the mechanical properties as compared with the control composition with no additives.

Pineapple leaf and cotton waste fibers known as abundant by-products in the agriculture and textile industry are combined for the first time to produce thermal insulating and flexible cellulose-based aerogel composites via an environmentally friendly and cost-effective freeze-drying process. The effect of total fiber content and the ratio of pineapple leaf fibers (PF) to cotton waste fibers (CF) on the density, porosity, morphology, durability, and thermal properties of aerogel composites are comprehensively investigated. The as-fabricated aerogel composites show an exceedingly low density of 0.019–0.046 g cm−3 with high porosity of more than 96%. Because of the porous structure inside, our aerogel composites exhibit outstanding heat insulation with extraordinarily low thermal conductivity of 0.039–0.043 W m−1 K−1 that is comparable to commercial insulation materials (mineral wool, fiberglass, polystyrene) and previous cellulose-based aerogels from recycled cellulose fibers, sugarcane bagasse, and rice straw. Interestingly, the combination of those fibers has remarkably improved the flexibility of our previous aerogels from pineapple leaf fibers only, in particular, the compressive modulus of aerogel composites (11.33–44.63 kPa) is 6 times higher than that of PF aerogels (5.73 kPa). The sheet of aerogel composite with a dimension of 28 × 28 cm which is rolled up shows no crack on its surface, demonstrating its excellent mechanical strength. The research results increase the possibility of applying the developed aerogel composites from biomass into practical insulation.

A new technology for forming multilayer mineral-wool mats by zig-zag pendulum layering of the primary mineral mat is described. It consists in forming variable-height loops in the primary mineral-wool mat in order to equalize the feed rate of the primary mineral-wool mat to the pendulum layering device and the circular velocity of the pendulum at the point of egress from it of the primary mineral-wool mat over the entire extent of the zig-zag layering pattern of the primary mat. Analytical formulas are given for calculating the parameters of the technology implementing the new method of zig-zag pendulum layering of mineral-wool mats.

Alkali activation is a promising utilisation route for mineral wool wastes, due to suitable chemical composition, high reactivity, and surface area. One key factor in the development of alkali-activated binders is the selection of the suitable alkali activator. Here, the effect of sodium hydroxide, sodium silicate, sodium aluminate, and sodium carbonate solution on the alkali-activation kinetics of two main types of mineral wools, stone wool and glass wool, is investigated. Setting time and compressive strength development results are presented, which are explained and discussed in the context of isothermal calorimeter data obtained at temperature of 40 °C. Sodium hydroxide and sodium silicate solutions provided fast reaction with both mineral wools, evidenced by high heat release, high early strength, and fast setting. The reaction with sodium aluminate solution took several days to initiate, but it produced high compressive strength after 28 days of curing with both mineral wools. Glass wool reacted and hardened rapidly with sodium carbonate solution, but stone wool reacted slowly with sodium carbonate and exhibited a low extent of reaction, likely due to lower extent of reaction of stone wool under less alkaline conditions. These results show that mineral wool alkali activation kinetics and binder gel formation are controlled by the activator type and highlight the importance of choosing the most appropriate activator for each desired application.

An examination of the corrosion under insulation phenomenon in insulated equipment at a petrochemical plant with the purpose of preventing corrosion-attributed failures was carried out. The study was performed after a risk-based inspection analysis identified the equipment with higher risks of developing corrosion under insulation. Visual inspections of several accessories located at several positions of the current process unit’s pipelines, heat exchangers, filters and pressure vessels were performed after the insulation was removed. Among the main findings, most accessories (nozzles, insulation support rings) located at the top of the equipment showed moderate corrosion. Additionally, there were differences in the results depending on the insulation material (mineral wool, foam glass or calcium silicate) covering the equipment/accessories. This work showed how adequate and timely monitoring and management of corrosion can successfully prevent costly and frequent failures associated with corrosion under insulation.

Corrosion of carbon steel under mineral wool insulation was studied using the electrochemical current noise (ECN) method. Intensities of corrosion were validated using gravimetry, and the form of corrosion confirmed using optical microscopy. The standard deviation of the current noise signal agreed with weight loss results and was demonstrated as a reliable indicator of the degree of corrosion under mineral wool insulation. Recurrence quantification analysis was used to extract feature variables from ECN signals, which were later used to develop a random forest model to identify the type of corrosion, i.e., uniform or localised corrosion. The trained model was successfully applied to predict the extent of localised corrosion associated with mineral wool insulation.

A method to determine the orientation and diameter distributions of mineral wool fibre networks using X-ray tomography and image analysis is presented. The method is applied to two different types of mineral wool: glass wool and stone wool. The orientation information is obtained from the computation of the structure tensor, and the diameter is estimated by applying a greyscale granulometry. The results of the image analysis indicate the two types of fibres are distributed in a 2D planar arrangement with the glass wool fibres showing a higher degree of planarity than the stone wool fibres. The orientation information is included in an analytical model based on a Euler–Bernoulli beam approximation. The model enables prediction of the transverse stiffness. It is indicated that the glass wool transverse stiffness is lower than the stone wool transverse stiffness. Comparison with experimental results confirms the assumption that the underlying deformation mechanism of mineral wool is the bending of fibre segments between bonds.

The total annual volume of mineral wool waste in the 27 European Union countries is expected to increase to 2.5 million tons per year by 2020. Unfortunately, mineral wool wastes are often considered unrecyclable, because their physical characteristics make them difficult to process. In many cases, the problem is caused by the material’s fibrousness. However, no studies have considered comminution methods for mineral wools. The objective of the present study is to investigate how various comminution mechanisms affect mineral wools’ physical characteristics, including appearance, bulk density, and fiber length and width. The study’s results show that compression-based methods (vibratory disc mill and hydraulic press) completely break down mineral wools’ fibrousness, whereas methods based on high cutting speeds affect bulk density and fiber length only moderately. In addition, the present study identifies a rapid method that can be used in a novel way to analyze a large number of mineral wool fibers.

A sorption method is proposed for cleaning industrial effluent with a new nanostructured complex sorbent based on Taganskoe deposit bentonite clay and mineral wool production waste. It is shown that with mechanical activation of bentonite clay together with mineral wool production waste there is an increase in clay particle content with a size less than 1 μm. It is established that for comprehensive and effective cleaning of electrolysis effluent from heavy metal ions a nanostructured complex sorbent (NSCS) is recommended based on bentonite clay from the 11th level and mineral wool production waste with observation of the following optimum conditions: 2:1 ratio of components in NSCS of 11th level bentonite clay : mineral wool production waste; rational mechanical activation scheme with grinding and nanostructuring of complex sorbent starting materials for 15 min; S:L = 1:100 (1 g of paste (in terms of dry substance) to 100 cm3 clean water); sorption time 3 h with constant stirring.

Soil material sampled from a reclamation experiment established in a former “Jeziorko” Sulphur Mine was analysed. The reclamation was carried out on a soil-less substrate with a particle size distribution of slightly loamy sand characterised by high acidity and poor sorption capacity. The different variants of the experiment consisted in the addition of post-flotation lime, mineral fertilisation, sewage sludge, and mineral wool to the reclaimed soil-less substrate. Next, the plots prepared in this way were sown with a mixture of grasses. A plot without any reclamation treatments served as a control. The analyses consisted in the determination of soil enzymatic parameters. The results obtained revealed a positive effect of the reclamation treatments on the analysed properties. All wastes and combinations thereof introduced into the degraded substrate stimulated catalase, protease, and urease activity. The activity of the other enzymes, i.e. dehydrogenases and acid phosphatase, as well as the level of fluorescein diacetate hydrolysis increased only in objects treated with sewage sludge. In turn, in objects receiving mineral fertilisation, a decline in the acid phosphatase activity was noted. In objects treated with mineral wool, the level of stimulation was dependent on the mode of application of this additive. In general, a mixture of 500 m3 ha−1 of mineral wool with the substrate proved more beneficial (with the exception of the acid phosphatase activity and fluorescein diacetate hydrolysis). A higher increase in the analysed enzymatic parameters was also found in objects treated with sewage sludge combined with post-flotation lime than in objects where sewage sludge was used alone.

This paper studied the crystallization behavior of mineral wool fibers when heated with the test method of combining differential thermal analyzer, X-ray diffractometer with scanning electron microscope; worked out the content of different crystallization phases with the reference intensity ratio method, and revealed the damage mechanism of the fibers when heated. The results showed that: the glass-transition temperature and the initial crystallization temperature of the mineral wool fiber measured by DSC was 712.5 and 854 °C respectively; while initial crystallization temperature measured by tube furnace was 700 °C which might be attributed to the fact that the heating rate of tube furnace was smaller than that of DSC. With the holding time of 4 h under 700 °C, diopside crystallized at first. As the holding temperature rose, the main crystallization phases were melilite and anorthite, also containing a small amount of diopside; additionally the amount of crystallization was the main reason for fiber damage.

The mineral wool sector represents 10 % of the total output tonnage of the glass industry. The thermal, acoustic and fire protection properties of mineral wool make it desirable for use in a wide range of economic sectors especially in the construction industry for the creation of low energy buildings. The traditional stone wool manufacturing process involves melting raw materials, in a coke-fired hot blast cupola furnace, fiberization, polymerization, cooling, product finishing and gas treatment. The use of alternative raw materials as torrefied biomass and sodium silicate, is proposed as an alternative manufacturing process to improve the sustainability of stone wool production, particularly the reduction of gas emissions (CO2 and SO2). The present study adopts a life cycle analysis (LCA) approach to measure the comparative environmental performance of the traditional and alternative stone wool production processes; process data are incorporated into a LCA model using SimaPro 8 software with the Ecoinvent version 3 life cycle inventory database. The CML 2000 and Eco-Indicator99 methods are used to estimate effects on different impact categories. The Minerals and Land use impacts in Eco-Indicator99 and the Eutrophication impact in CML2000 increase between 2 and 4 % for the alternative process instead of the traditional one. Similarly, the ecotoxicity-related impacts increase between 9 and 24 % with the use of the alternative process. However these increases are compensated by concomitant impact decreases in other categories of impact; consequently, the three areas of impact grouped by individual Eco-indicator 99 impacts, show environmental benefits improvements between 6 and 15 % when using the alternative process based on torrefied biomass and silicate instead of the traditional process based on coke and cement use.

The structural fire behavior of typical load-bearing drywall systems, consisting of light cold-formed steel (CFS) studs, sheathed with single or double layers of gypsum plasterboards and air cavity or mineral wool insulation, is investigated. For that purpose, an efficient numerical modeling approach with satisfying accuracy is developed and validated against experimental and numerical results available in the literature. Heat transfer and structural analyses of the investigated drywall assemblies are carried out, employing the computational tools ANSYS CFX and ADINA, respectively. Transient heat transfer analyses provide the spatial and temporal temperature variation over the drywall assembly, which is assumed to be exposed to the standard ISO 834 fire curve from one side. Thermal simulation results are then introduced in the subsequent structural analyses, where the load-bearing capacity of the CFS studs under fire conditions is estimated, by means of Geometry and Material Nonlinear Analyses accounting for Imperfections (GMNIA). The load-bearing capacity assuming uniform cross-sectional temperature distributions is also evaluated and compared to the respective predictions under non-uniform temperature profiles. Results obtained by varying the imposed load or the applied temperature (fire duration), are compared to predictions of existing and literature-proposed fire design guidelines. EN 1993-1-2 provisions lead to average underestimation of the load-bearing capacity by approximately 20%, while the literature-proposed methods are found to underestimate the load-bearing capacity by 5% to 15%. The limitation of using a critical temperature of 350°C for the structural fire design of thin-walled sections is found to be rather conservative, since the investigated CFS studs are able to exhibit satisfying fire performance also under higher temperature conditions.

Mineral wool waste is often considered unrecyclable, due to its difficult-to-process physical composition, and potential microbial contamination in the post-consumer products. Total mineral wool waste generated in the EU is growing continuously and is currently over 2.3 Mt annually, volumetrically accounting for the largest single waste source in some landfills. Here, we take advantage of the alkali-soluble nature of the rockwool waste, and use a combined mixing and dissolution method to prepare this otherwise unusable waste for geopolymerization, with up to 33 % inclusion in the final product. This mixing and dissolution step enables sufficiently high solids content to form a castable geopolymer paste, which forms a rigid matrix and a compressive strength of 12.8 MPa, sufficient for structural applications. This is the first time mineral wool waste has been used as a geopolymer precursor. FESEM and XRD analysis of the formed products were performed to verify geopolymer formation. Using the preparation reported here, otherwise unrecyclable mineral wool waste can potentially be turned into a valuable raw material for geopolymer materials.

Hollow brick blocks have found widespread use in the building industry during the last decades. The increasing requirements to the thermal insulation properties of building envelopes given by the national standards in Europe led the brick producers to reduce the production of common solid bricks. Brick blocks with more or less complex systems of internal cavities replaced the traditional bricks and became dominant on the building ceramics market. However, contrary to the solid bricks where the thermal conductivity can easily be measured by standard methods, the complex geometry of hollow brick blocks makes the application of common techniques impossible. In this paper, a steady-state technique utilizing a system of two climatic chambers separated by a connecting tunnel for sample positioning is used for the determination of the thermal conductivity, thermal resistance, and thermal transmittance (U value) of hollow bricks with the cavities filled by air, two different types of mineral wool, polystyrene balls, and foam polyurethane. The particular brick block is provided with the necessary temperature- and heat-flux sensors and thermally insulated in the tunnel. In the climatic chambers, different temperatures are set. After steady-state conditions are established in the measuring system, the effective thermal properties of the brick block are calculated using the measured data. Experimental results show that the best results are achieved with hydrophilic mineral wool as a cavity filler; the worst performance exhibits the brick block with air-filled cavities.

Results are provided for preparation of fused cast chromium corundum refractories using a charge of waste lump baddeleyite-corundum refractories after service in glass-making furnaces. It is shown that fusion cast chromium corundum refractories, containing 41,2 and 62.1 % Cr2O3 and prepared from a charge using baddeleyite-corundum refractory scrap, have high corrosion resistance in molten mineral wool compared with fused cast baddeleyite-corundum and chromium-aluminum-zirconium refractories of industrial grades ER 1711 and KhTs-45.

The construction and demolition (C&D) industry has been identified as a major source of waste. European Union legislation states that, by 2020, 70 % of C&D waste must be prepared for reuse, recycled or recovered. European Union member states must increase their C&D waste recycling percentages in order to meet this binding target. Utilization of mineral wool waste, often considered unrecyclable, could improve the recycling percentage of C&D waste. In this article, mineral wool production and waste volumes are estimated based on information from the Eurostat database. A literature survey is conducted to collect information about mineral wool material properties, current recycling methods, and barriers to recycling of mineral wool, and suitable methods for separating mineral wool from C&D waste streams and the economic viability of mineral wool recycling are discussed. It is noted that accurate estimation of mineral wool waste volumes is problematic due to the fragmented nature of available data. Based on the literature review, current methods for recycling mineral wool waste include utilization of mineral wool waste as a raw material in various products. Barriers to recycling include economic questions and issues related to the purity and health effects of mineral wool waste. Material properties of mineral wool waste, such as fire resistance, could provide improved properties in products utilizing mineral wool waste as a raw material.

Results are provided for preparation of fusion-cast chromium-spinelid refractories using lumps of baddeleyite-corundum refractory waste after service in glass melting furnaces. It is shown that fusion-cast chromium-spinelid refractories, containing 31.2 and 50.4% Cr2O3 and prepared from a charge using broken vessel refractory, has improved corrosion resistance in molten mineral wool compared with fusion-cast baddeleyite-corundum and chromium-aluminum-zirconium refractories of commercial grades ER 1711, KhATs-30, and KhTs-45.

Ways to use gabbro-basalt raw material for the production of mineral wool and industry’s demand for it are examined. The reasons for quality and composition variations of the raw material are shown. Recommendations for solving the raw material problem are made for producers — preparation of domestic deposits based on geological prerequisites, mineral-technological mapping of objects and organization of selective raw materials production.

For the first time under the auspices of the Bureau International des Poids et Mesures (BIPM), seven national metrology institutes (NMIs) participated in an international interlaboratory comparison on thermal-conductivity measurements by the guarded hot-plate method. Measurements were conducted successively by all participants on the same set of specimens of insulating materials (mineral wool and expanded polystyrene) at temperatures ranging from 10 °C to 40 °C, according to the International Standard ISO 8302. This protocol aims to minimize issues of material variability by circulating the same pairs of specimens among the laboratories following the strict format of a round-robin test program. This comparison is a pilot study which is intended as a first stage for future key comparisons between NMIs. The descriptive analysis of obtained results shows good agreement between laboratories for the mineral wool (MW) specimens and the thicker specimens of expanded polystyrene (EPS), with relative deviations within the uncertainties of measurement. A positive drift of thermal-conductivity values, which has appeared progressively during the comparison process, seems to be correlated with the size of the metering area of the guarded hot plates used. A statistical analysis was applied to repeated thermal-conductivity measurements at 23 °C, to identify anomalous and outlying data, to assess the within- and between-laboratory variability, and to evaluate the participant laboratories’ performance.

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.

The present paper is aimed at recycling of coal ash and blast furnace slag to produce mineral wool. Considering the mineralogical constitutions of coal ash and blast furnace slag, the primary quaternary slag compositions of CaO-SiO2-MgO-Al2O3 with basicity (mass ratio of CaO to SiO2) ranging from 0. 5 to 0. 9 and alumina ranging from 5% to 20% were investigated through a rotating cylinder method. The experimental results indicated that the viscosities decreased with increasing basicity above the liquidus temperature, and increased with increasing alumina content, and the maximum values were reached and as the alumina content was 20%, followed by the decrease with further increasing alumina content due to its amphoteric behavior. The amphoteric behavior of Al2O3 also performed in the relationship between viscosity and non-bridging oxygen per tetrahedrally-coordinated atom (NBO/T), and the viscosities decreased with increasing the NBO/T except the slag with a basicity 0. 5 and Al2O3 20% which have a low NBO/T value and a low viscosity than others.

Fire Technology, 48 (3), ISSN:0015-2684, ISSN:1572-8099

On the basis of analyzing furnace thermal and gas-dynamic operation for polymerization of mineral wool objects advantages are demonstrated for using a gas movement circulation scheme. The required structural changes for furnace working space operation are substantiated for obtaining high technical and economic indices from data for material and thermal balances.

A numerical model was developed for a floating floor with an inserted viscoelastic layer to predict the structure-borne noise (SBN) in ship cabins. In cabins, high-density mineral wool is usually used as an impact-absorbing material. The theoretical model consisted of multipanel structures lined with high-density mineral wool. The predicted results for SBN when a floating floor with an inserted viscoelastic layer is used were compared with the measurements done on a cabin mock-up. Various floating floors with inserted viscoelastic layer structures were studied, and the effects of variations in the thickness, density, and fiber direction of the high-density mineral wool were investigated. Comparisons of the predicted results and the experimental results showed that the developed model could be an effective tool for predicting SBN in ship cabins.

The thermal conductivity of several types of mineral wool-based materials, namely, materials with hydrophobic admixtures, hydrophilic admixtures, and without any admixtures are measured as a function of moisture content from the dry state to the partially water saturated state. An impulse technique is employed for the measurements using both surface and needle probes. The data are analyzed using the Bruggeman effective media concept for different shapes of inclusions and Wiener’s basic formulas. It is found that for most materials, the experimental data for thermal conductivity in the range of low moisture content are close to the lower Wiener’s bound but in the range of higher moisture content the data are close to the upper Wiener’s bound.

An alternative interpretation of the mechanism of fiber formation by melt blowing of primary filaments in the production of ultrafine basalt is proposed. Relationships between the secondary fiber length and process parameters are considered.

This paper presents the results of an experimental study of the isotherms of water vapor sorption by glass-fiber and mineral-wool products, expanded polystyrene plates, and ecowool. It has been shown that the equilibrium specific moisture content of glass-fiber and mineral wool products depends on the binder content and density and that of expanded polystyrene plates is density-dependent.

The properties of basalt fiber obtained using low-temperature plasma are investigated. Basalt wool possesses good physical-mechanical properties. Its chemical stability depends on the composition of the initial raw material. Surfaces with temperature to 500°C can be insulated using mineral wool made from basalt obtained from the Vasil’evskoe deposit and to 700°C for basalt from the Suduntuiskoe deposit.

There is a growing desire to improve the properties and use of nonwood plant materials as supplements to wood materials for wood cement-bonded boards (WCBs). This study was conducted to determine the comparative properties of WCBs containing various amounts of discontinuous inorganic fiber materials, such as alkali-resistant glass fiber, normal glass fiber, mineral wool, and nonwood plant materials such as retted flax straw and wheat straw particles. Tested cement-bonded boards were made at wood/additive compositions of 100/0, 90/10, 80/20, 70/30, 60/40, and 50/50 (weight percentages). Seventy-eight laboratory-scale WCBs were produced. Various board properties, such as the modulus of rupture (MOR), internal bonding strength (IB), water absorption (WA), thickness swelling (TS), and linear expansion (LE), were studied. The test results showed that three types of discontinuous inorganic fiber used as reinforcing materials in composites significantly enhanced and modified the performance of WCBs. The mechanical properties and dimensional stability of cement-bonded board were significantly improved with increasing amounts of the additives. MOR and IB were increased; and WA, TS, and LE of boards were reduced by combination with the inorganic fiber materials. The results also indicated that combination with retted flax straw particles only slightly increased the MOR of boards, and wheat straw particles led to marked decreases in all the mechanical properties and the dimensional stability of WCBs.

The objective of this work was to compound mineral wool with wood particles in the production of particleboards of reduced flammability. Three series of boards with various contents of mineral wool (10, 20, 30 wt%) were successfully manufactured using urea-formaldehyde resin as binder. Thickness swelling, mechanical and thermal properties as well as ignitability of the boards were assessed. It occurred that reduced ignitability is accompanied by a decrease in mechanical performance.

A method for estimation of the heat-shielding properties of gas-filled mineral wool insulators is considered, which takes into account the mechanism of interrelated heat and mass transfer processes and their intensities, depending on the service conditions, design specifics, and technological parameters of the insulating material.

A technological study of basic and ultrabasic Karelian rocks as mineral wool raw material was conducted. It was found that ultrabasic rocks with a ratio of CaO: MgO ≥ 0.5 are the optimum raw material for production of mineral wool by the cupola method. Promising sections of these types of rocks for development are identified.

Experiments are described concerning the differences in redox properties and biodurability of natural asbestos fibres and an experimental stonewool fibre incubated in Gamble solution and reconstructed surfactant fluid. Crocidolite exhibits a significantly higher oxidative potential compared to the tested stonewool fibres. The oxidative acitivity of both types of fibres is not constant during incubation over several weeks, but rather shows a sinoidal curve including reactivities much higher than those at the beginning of the incubation. A continuous loss of mass is concluded not to be definitively connected with a continuous loss of toxicity.

The objective of this study was to investigate whether occurrence of pleural plaques is associated with exposure to mineral wool. The occurrence of pleural plaques on routine chest radiographs of 933 persons employed in the mineral wool manufacturing industry and 865 referents was compared. Twelve men from the mineral wool industry had pleural plaques, as against three of the referents (P > 0.05). The occurrence of pleural plaques among men in the mineral wool industry was not associated with an increased exposure to mineral wool or with length of time between start of employment and time of chest radiograph. The results do not support the notion that inhalation of man-made mineral fibers causes pleural plaques. It must, however, be conceded-keeping in mind the limits imposed by the study size-that nor do they provide grounds for refutation of such a hypothesis.

The boundary of the ‘analytical’ thermal stability of a phenol-formaldehyde-urea binder was determined, assuming the lack of nitrogen losses as a criterion of thermal stability.

Structural sandwich elements typically have two thin metal faces and a lightweight core. The core may be polyurethane or polyisocyanurate foamedin situ, or it may be formed from either rigid plastic foam or mineral wool slabstock. It is particularly in the latter case that durability problems may arise which have not been properly addressed by the industry. This paper considers appropriate test regimes for considering the durability of the adhesive bond between the core and the faces. In the case of panels with a core formed of mineral wool lamellae, it also considers possible degradation of the core material. The results of these tests demonstrate that commercially available mineral wools do not have uniform durability. It is necessary to pay particular attention to this factor when choosing core material for structural sandwich panels. Although the research described in this paper was conducted with mineral wool core metarial in mind, it is believed that the procedures are equally applicable to other materials. They are being codified in European recommendations for sandwich panels with additional recommendations for panels with mineral wool core material, published jointly by the European Convention for Constructional Steelwork (ECCS) and the International Council for Building Research Studies and Documentation (CIB).

This paper presents a study on the deformation of anisotropic fibrous porous media subjected to moistening by water in the liquid phase. The deformation of the medium is studied by applying the concept of effective stress. Given the structure of the medium, the displacement of the solid matrix is not taken into account with respect to the displacement of the liquid phase. The transport equations are derived from the model proposed by Narasimhan. The transport coefficients and the relation between the variation in apparent density and effective stress are obtained by test measurements. A numerical model has been established and applied for studying drip moistening of mineral wool samples capable or incapable of deformation.

We identified two types of corrosion resistant refractories with peculiarities of phase composition (mullite and mullite-corundum). In the first case the formation of a contact zone saturated with products from the solution of refractory (mainly SiO2) occurs. In the second, when the refractory contains corundum, there is a clear reaction zone due to the penetration of melt into the refractory between the filler grains. This is explained by the different degree of wettability of the mullite and corundum in relation to molten slags.

Since the seventies, energy conservation in all its forms has grown. This mindset has lead to the addition of thermal insulation in existing buildings, without concern for the existing electric cables. The addition over-insulates the cables, inhibiting heat dissipation, and possibly creating a hazardous situation.

Asbestos containing material (ACM) inside buildings is an important concern for the health of their occupants. In France, for the assessment of airborne asbestos concentrations inside building, we use the indirect TEM measurement method constantly improved from 1978 on. By contrast, in the U.S.A. and UK the direct method is used. We have carried out a study in order to compare mass and numerical concentration fibres from the same samples, the tendency being now to express the results in fibre/litre. Concerning asbestos fibres released from man made mineral fibres (MMMF), optical microscope is used and results are expressed in numerical concentrations. Epidemiological studies of different occupational cohorts suggest that amphibole fibres present a greater health risk than chrysotile. Concerning indoor pollution by mineral wool, the health hazard seems negligible. The appraisal of this public health problem remains to be done. In France, a multidisciplinary study group has been created to provide advices related to corrective actions. Information on this public health problem is expected from the epidemiologic longitudinal survey, still in progress, of a cohort of workers, exposed to ACM in Paris university buildings.

The northern part of Venezuela is the area with the highest urban growth rate. Three cities, Caracas, Valencia and Maracay, located in the industrial states of the north central region, each have population over one million. These cities consume more than 10 million M.T. of aggregates each year. With few large limestone deposits available and with numerous national parks and recreational areas located throughout these states, the producers of aggregates for the construction industry are trying to use another type of raw material. Only two rocks can substitute for the limestone as aggregates in the northern part of Venezuela: amphibolite and serpentinite. Actually the first is being mined on a large scale. The amphibolite deposits constitute large bodies with thickness over 50 metres and they are associated with schists and calcareous phyllites. The fresh amphibolite is extremely coherent and uniform and constitutes an excellent material for the aggregates industry. Actually more than 600.000 M.T. are produced annually from deposits located quite near to the city of Valencia. Because of the mineralogical and chemical characteristics, the first 3 metres of the rock have to be used as road filler, whereas the hard material is used as aggregates, at least three types are produced, and as an asphaltic carrier. According to geological data, more than 20 million M.T. of good quality amphibolite have been outlined in the north-central part of the country constituting one of the largest proportions of raw material for the aggregate industry, mineral wool, granules, and asphaltic carrier, located out outside of the national parks, recreational areas and green belt boundaries.

This paper presents a method based on a method of selecting thermal insulation inrelation to the minimum expenditure, taking into account he capital investment (cost of materials) and runing expenditure (heat loss) which is analogous to the method of determining the economically reasonable resistance to heat transfer in public and industrial buildings. The proposed method makes it possible to solve the problems of the thermal insulation for both actual glass-melting furnaces and also from the point of view of the development of the production of thermal-insulation materials in varius regions of the Soviet Union.

Effects of growth medium physical conditions were studied. Peat and two series of peat mixed with hydrophobic mineral wool or perlite in three mixing ratios were prepared. Growth media porosities were characterized by the “standardized time method” and seedling development by measurements of stem length and fresh and dry weight.

An experimental study has been carried out and it was observed that inorganic mineral fibres of the slag wool and rock wool types exhibit a physical disintegration and morphological modifications on the fibre surface when these fibrous products have been exposed to water vapour or immersed in a liquid water medium under heating at temperatures up to 100° C for a period of several months. The physical disintegration transformed the fine and thread-like fibres into small segments and granules. Scanning electron microscopic examinations showed that a rough and eroded fibre surface was formed for those fibres which have been immersed in water and heated at temperatures below 60° C for about 3 months and that a reticular network structure or “honeycomb morphology” was developed on the Jibre surface for those fibres which have been immersed in water and heated at temperatures above 85° C and up to 100° C for about 4 weeks. Measurement of the pH value of the water solution and thermogravimetric analysis of the disintegrated fibres suggest that these modifications of the fibrous products are caused by two possible mechanisms: chemical leaching and chemical hydration. Thermal conductivity measurements showed that the disintegrated fibres have thermal insulating values about 15% lower than that of the normal and thread-like fibres.

A test program was undertaken by the U. S. Mine Safety and Health Administration to evaluate various materials for protecting aluminum overcast constructions against fire. Selected coatings and one covering were tested under large-scale, simulated mine fire conditions to determine their effectiveness as a fire barrier for protection of aluminum. Coatings consisting of expanded vermiculite, limestone, and portland cement; mineral wool fibers in hydraulic setting, inorganic binders; cellulose mixed with liquid sodium silicate; and a fiberglass-reinforced surfacebonding mortar were particularly effective in protecting the aluminum structures against the heat of the simulated mine fire. Three inches of a ceramic-fiber blanket and a four-inch coating of phenolic spray foam also proved to be relatively effective barriers for fire protection under the conditions of the test.