Cellular Glass Research Articles

Limit load and failure mechanisms of soda lime glass foam

Foamed glass is widely used in the industry as an insulating material. However, its mechanical properties are not well-investigated yet. Foamed glass is produced from glass waste that causes discrepancy in mechanical properties of the final product. This paper shows a way to increase the limit of the load capacity of foamed glass, which is very fragile and sensitive to mechanical and thermal loading conditions. In this paper, three different methods of load application on cellular glass structure (rough contact, resin and flour interfaces) and their influence on failure mechanisms were investigated in detail. The results of numerical analyses, based on finite elements method and compression strength tests using the digital image correlation method, indicate that the overall strength of the material is limited by boundary effects. A careful adjustment of the interface property is the main factor to draw useful conclusions and to extend load limits of cellular glass in engineering applications.

Certain Building Materials with Respect to Their Thermal Properties as Well as to Their Impact to Environment

Thermal properties of certain building materials were studied with respect to environmental aspects. The building materials with significant insulation properties were laboratory tested using the special equipment based on Peltier module. During the experimental work, the samples of the following materials were tested: Expanded polystyrene (EPS), Autoclaved aerated concrete (AAC): Ytong, Calcium Silicate Board: Super-Isol and Foam glass (Cellular Glass Insulation): PERINSUL. The temperature was measured directly in connection of material with the Peltier module as well as in the distances of 5mm, 27.5mm, 50mm and 95mm from the Peltier module. The temperature taken at the surface of Peltier module reached -22°C, a typical temperature in the cold winter season. The results of the laboratory experimental work were modelled using the graphic representation. Modelling the thermal distribution will help to determine the ideal material thickness in the design of the building insulation.

Comparison of Cushioning Mechanisms between Cellular Glass and Gabions Subjected to Successive Boulder Impacts

AbstractGabions are the most commonly adopted cushion layer for shielding rigid debris-resisting barriers against boulder impact. Despite the prevalent use of gabions, they comprise heavy rock frag...

Rice Hulls as a Renewable Complex Material Resource

As a result of rice grain processing, a big amount of waste (up to 20%) is produced. It is mainly rice hulls. The main components of rice hulls are cellulose, lignin and mineral ash. The mineral ash quantity in rice hulls varies from 15 up to 20%, by weight of the rice hulls. The mineral ash consists of amorphous silica (opal-type). Due to the high content of silica in rice hulls, the material burns with difficulty under natural conditions, and it is biodegradably destroyed only with difficulty, when composted. Utilization of rice hulls then becomes an ecological problem due to huge rice production and its continuous growth. At the same time, the annual quantity of silica content in rice hulls is comparable with the quantity of amorphous silica produced as a mineral resource. The issue of manufacturing cellular glass silica construction materials from rice hulls as a renewable resource is discussed in this paper. The utilization technology is based on an amorphous silicon oxide with the use of energy from the combustion of the organic component of rice hulls.

Физико-химические особенности получения ячеистых стекломатериалов на основе стеклобоя и золошлаковых отходов теплоэнергетики

Физико-химические особенности получения ячеистых стекломатериалов на основе стеклобоя и золошлаковых отходов теплоэнергетики

A Continuum Damage Mechanics Model for the Static and Cyclic Fatigue of Cellular Composites.

The fatigue behavior of a cellular composite with an epoxy matrix and glass foam granules is analyzed and modeled by means of continuum damage mechanics. The investigated cellular composite is a particular type of composite foam, and is very similar to syntactic foams. In contrast to conventional syntactic foams constituted by hollow spherical particles (balloons), cellular glass, mineral, or metal place holders are combined with the matrix material (metal or polymer) in the case of cellular composites. A microstructural investigation of the damage behavior is performed using scanning electron microscopy. For the modeling of the fatigue behavior, the damage is separated into pure static and pure cyclic damage and described in terms of the stiffness loss of the material using damage models for cyclic and creep damage. Both models incorporate nonlinear accumulation and interaction of damage. A cycle jumping procedure is developed, which allows for a fast and accurate calculation of the damage evolution for constant load frequencies. The damage model is applied to examine the mean stress effect for cyclic fatigue and to investigate the frequency effect and the influence of the signal form in the case of static and cyclic damage interaction. The calculated lifetimes are in very good agreement with experimental results.

The expansion kinetics of cellular glass in the thermoplastic state under the hydrated mechanism of gas formation

The problems of extending cellular glass in the pyroplastic state under a hydrated mechanism of gas formation are considered. It is established that the use of water vapor allows varying the product’s properties over wide limits and get ecologically safe materials. It is shown that the volume of gases released during the reaction and the viscosity of the melt are the factors determining the extension of cellular glass. The kinetic characteristics of the extension of the cellular structure of glass in the thermoplastic state are determined.

Cellular Glass Designing and Processing Technology for Cryogenic Insulation

Cellular Glass Designing and Processing Technology for Cryogenic Insulation

Cellular Heat Insulation Building Glass Materials Based on Wastes from Thermal Power Plants and Ferrous Metallurgy

The physical-chemical processes involved in the formation of the cellular structure of heat-insulation building glass materials as a result of thermoplastic sintering of batch at temperatures 600 – 870°C are examined. Such a cellular glass formation process occurs because the significant gas-phase volume formed at low viscosity diffuses in the thermoplastic ceramic mass and in so doing creates the pore structure of the cellular heat-insulation glass.

Optimization of a Cellular Glass Ceramic Produced from Water Potabilization Sludge for Structural and Chemical Applications

Waste sludge generated in the potabilization of surface water is used to produce cellular materials by mixing with clay and firing at 1 250 °C. An iron‐rich glassy matrix with crystals of mullite and albite is formed. Porosity is generated by the slow release of H2O, which originates from the dehydroxilation of lepidocrocite at high temperature. The sludge/clay ratio and the sludge granulometry determine the properties of the product: from highly porous cellular foams to denser materials with high strength. Laboratory tests for both kinds of products show that the latter can be used as aggregates for low‐density structural concrete. The former serve as a support material for the catalytic reduction of NOx in exhaust gases. Deposition conditions for Fe‐ and Pt‐nanoparticles are optimized by experimental design, resulting in NOx‐conversion rates close to 100%.

Host cell surfaces induce a Type IV pili-dependent alteration of bacterial swimming.

For most pathogenic bacteria, flagellar motility is recognized as a virulence factor. Here, we analysed the swimming behaviour of bacteria close to eukaryotic cellular surfaces, using the major opportunistic pathogen Pseudomonas aeruginosa as a model. We delineated three classes of swimming trajectories on both cellular surfaces and glass that could be differentiated by their speeds and local curvatures, resulting from different levels of hydrodynamic interactions with the surface. Segmentation of the trajectories into linear and curved sections or pause allowed us to precisely describe the corresponding swimming patterns near the two surfaces. We concluded that (i) the trajectory classes were of same nature on cells and glass, however the trajectory distribution was strikingly different between surface types, (ii) on cell monolayers, a larger fraction of bacteria adopted a swimming mode with stronger bacteria-surface interaction mostly dependent upon Type IV pili. Thus, bacteria swim near boundaries with diverse patterns and importantly, Type IV pili differentially influence swimming near cellular and abiotic surfaces.

Development of Resource-Saving Cellular Glass Technology and Materials Based on it

The advantages and drawbacks of a modern thermal insulating material – cellular glass (foam glass) – and the use of manmade waste (in particular, thermal power plant ash-slag waste) in its synthesis were described. The results of studies into the development of composites and temperature-time synthesis modes of effective energy-saving cellular glass and materials based on it were shown, including the experimental samples of insulating boards and blocks with density of not more than 500 kg/m3; experimental samples of porous granules for lightweight concrete and thermal insulating fillers with density of not more than 250 kg/m3 –. Technology of cellular glass using the Novocherkassk State District Power Plant ash-slag waste was described. The developed technological solutions allow setting physical and mechanical properties of materials based on cellular glass (density, porosity, thermal conductivity, compressive and bending strength) by varying the amount of ash-slag waste in its composition.

Development of Compositions and Technological Parameters for the Synthesis of Cellular Glass Heat-Insulation Construction Materials with Prescribed Density

The possibility of synthesizing heat-insulation construction materials with prescribed density on the basis of cullet, slag from a metallurgical plant, and ash-slag wastes from thermal power plants (TPP) is examined. The effect of the type and amount of pore-formers on the structure and properties of cellular glass heat-insulation construction material is analyzed. The compositions, technological parameters, and temperature – time regimes are worked out for the synthesis of tiles, construction – heat-insulation blocks, and porous fillers from cellular glass based on technogenic raw material for light-weight concretes.

Cellular glass obtained from non-powder preforms by foaming with steam

Cellular glass, or foamed glass, has been obtained as a result of the heating (to 700–800°C) of heavy and strong preforms formed due to the binding properties of the silicate additives. Durability of the preforms reached 6MPa at the density of 1.8g/cm3. The main expanding agent in the composition is steam, which can also be a carbon oxidizer and increase the amount of the evolved gases and decrease the density of the foamed glass obtained. As a result of changing the initial composition structure, the density of the obtained foamed glass varied from 0.14 to 0.6g/cm3, its breaking strength - from 0.6 to 5.0MPa. and heat conductivity – from 0.045 to 0.15W/(m·К), respectively. The speed of expansion of the preforms had an extreme character with the induction period typical for topochemical reactions. The obtained cellular materials possessed a distinct crystalline structure. The experiments showed the possibility of obtaining cellular materials with acceptable properties from different types of glass for the solution of environmental tasks. Various technological methods of obtaining cellular material blocks from preforms of various forms were tested to use them for thermal insulation and facing materials.

Study on the Methods for Measuring Closed Cell Content of Cellular Glass and its Thermal Insulation Performance

The principle of measuring cellular glass by automatic densimeter was studied. The effect of pressure on closed cell content was researched in order to optimize the measuring pressure. The influence of closed cell content on the insulation property was analyzed by measuring thermal conductivity. The results showed that cell structure of cellular glass can distort or even be damaged with the increasing of pressure and the first condition for obtaining accurate closed cell content was to optimize the measuring condition and determine appropriate pressure. Closed cell content affects the insulation property of the cellular glass significantly.

Experimental study on the thermal conductivity and moisture ingress in closed-cell mechanical pipe insulation systems at below ambient conditions (ASHRAE RP-1646)

Mechanical pipe insulation systems are commonly used around chilled water pipes to reduce heat gain from the ambient. Often water vapor condensate accumulated inside the pipe insulation and it might lead to a degradation of the insulation thermal conductivity. There are not any standardize test methods for characterizing this phenomena and literature showed that the values of the thermal conductivity of pipe insulation systems are different from flat slabs due to the radial configuration and the presence of split joints. This article first introduces work on the improvement of a novel test apparatus for measuring pipe insulation thermal conductivity at below ambient temperature. Then, measured from the improved experimental devices, new experimental findings on the thermal conductivity of three closed-cell pipe insulation systems, that is, cellular glass, elastomeric rubber and PIR, are presented. The first two of these insulation materials were tested without a sheet or film vapor retarder whereas the third was tested with a sealed polyvinylidene chloride plastic film vapor retarder. Data showed that these closed-cell pipe insulation systems were resistant to the moisture ingress, and the thermal conductivity slightly increased with the moisture content. The impacts of joint sealant and vapor jacket were key factors to the system moisture ingress and should be carefully considered during system design and installation. The results in this article showed the importance of including appropriate insulation thickness safety margins due to the presence of insulation joints and the possible joint sealant in order to achieve condensation control.

Comparison tests of cellular glass insulation for the development of cryogenic insulation standards

Standards for thermal insulation used in applications between ambient and low temperatures, below 100 K, require test data under relevant conditions and by different laboratories to develop data sets for the proper comparisons of materials. This critically important technology is needed to provide reliable data and methodologies for industrial energy efficiency and energy conservation. Under ASTM International's Committee C16 on Thermal Insulation, two standards have been issued on cryogenic thermal insulation systems. Thermal conductivity data sets have been taken using identical flat-plate boiloff calorimeter instruments independently operated at the Cryogenics Test Laboratory of NASA Kennedy Space Center (KSC) and the Thermal Energy Laboratory of LeTourneau University (LETU). Precision specimens of cellular glass insulation were produced for both laboratories to provide the necessary comparisons to validate the thermal measurements and test methodologies. Additional specimens of commercial cellular glass pipe insulation were tested at LETU to compare with the flat plate results. The test data are discussed in relation to the experimental approach, test methods, and manner of reporting the thermal performance data. This initial Inter-Laboratory Study (ILS) of insulation materials for sub-ambient temperature applications provides a foundation for further ILS work to produce standard data sets for several key commercial materials.

Resource-Conserving Technology of Heat-Insulation-Decorative Glass-Composite Material Based on Ash-Slag Wastes

The possibility of producing heat-insulation glass- and glass-ceramic composite construction material based on ash-slag wastes from thermal electric power plants that meets modern construction standards and the physical-mechanical, heat-insulation, and environmental requirements was examined. Compositions and technology for obtaining the constituent parts of heat-insulation-decorative glass-composite material based on ash-slag wastes—cellular heat-insulation glass and slag-sital—with the required physical-chemical properties were developed. The choice of cement binder was substantiated and the mechanism of adhesion between the components of the composite was determined.

Elaboration and characterization of a cellular glass based cullet loaded with carbon fibers

The foams glass whose porosity is very important, are counted among the new glass products that meet certain desired comfort needs in the particular building area (thermal and acoustic insulation).The objective of this study is to determine the influence of the carbon fibers addition influence on the porosity, the thermal insulation and dielectric loss of foams glass prepared by sintering at 800°C, which opens the way to foam glass many possibilities for industrial to extend their opportunities that are very varied from thermal insulation to electromagnetic waves absorption. The carbon fibers addition used for this study is 1, 2, 3.5 and 5wt% in relation to the foam glass load. Physico-chemical analysis techniques such as SEM-EDS, porosity, thermal insulation, differential thermal analysis, and dielectric tests have been used for the foams glass characterization.The obtained microstructure results clearly show that the 5wt% carbon fibers addition increases the foam glass porosity which leads to low thermal conductivity (λ=0.0281W/m°C) and increases its thermal insulating capacity. Furthermore the specific dielectric properties as real permittivity (ɛʹ=2.7619) and high dielectric loss (tanδ=0.02969) favor the use of these glass filled foams with carbon fibers in the electromagnetic waves microwave absorption in the weakest working frequencies (mobile phones and Wi-Fi).

Oxidation of carbon by water vapor in hydrate gas-formation mechanism in manufacture of cellular glass

Gas formation in production of a cellular glass is considered for the case when the hydrate mechanism is operative and water vapor is used as oxidizing agent. It is shown that the presence of carbon in the system leads to a steam conversion and larger volume of released gases. Differences in the structure of materials obtained with different carbon reducing agents and formation depth of polysilicates in the raw material are discussed. It is shown that a light cellular glass can be obtained.