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Foamed Glass

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Abstract ................................................................................................................................................... 2 Introduction ............................................................................................................................................. 3 Figure 1. Soap foam bubbles .............................................................................................................. 3 Foamed glass........................................................................................................................................... 4 Figure 2 Foamed Glass ....................................................................................................................... 5 Production Process .................................................................................................................................. 5 Figure 3 Porous Foamed Glass ........................................................................................................... 5 Figure 4 Processing of Foamed glass .................................................................................................. 6 Properties of foamed glass ...................................................................................................................... 6 Figure 5. Foamglass in different shapes.............................................................................................. 8 Strength and deformation properties ....................................................................................................... 8 Table 1.Deformation/settlements (short term/day 1) in foam glass material ...................................... 9 Table 2.Estimated creep deformations after day 1 at stress level* 300 kN/m2 permanent load......... 9 Foamed Glass In Road Projects .............................................................................................................. 9 Figure 6.Installing Steel Tube ........................................................................................................... 11 EXAMPLES WHERE FAOMGLASS IS USE IN ROAD PROJECTS .............................................. 11 Advantages of Foamed glass ................................................................................................................ 12 Disadvantages of Foamed glass ............................................................................................................ 15 Conclusion ............................................................................................................................................ 15 References ............................................................................................................................................. 17

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Abstract Granulated foamed glass is produced by recirculating waste glass. It is also known as cellular glass. It is a light weight, opaque glass material having a closed-cell structure. It is an excellent bulk material for civil construction and insulation purposes. It is a lightweight, extremely fine-pored expanded glass with millions of pores. Since no diffusion can take place, the material is watertight and achieves an efficient barrier against soil humidity. Foamed glass is produced using an environ-mentally friendly recycling technology for contaminated and toxic material. The normal grain size is in the range 10 60 mm. When placed and compacted in a drained fill the least unit density will be 300 350 kg/m3 depending on the compaction machinery and compaction efforts. Besides the outstanding mechanical and thermal properties of the product, foamed glass manufacture is an exemplary process for waste recycling on an industrial basis. Foam glass can be manufactured fully out of waste glass, with only a minimum of additives. The material may be used as a lightweight fill material, as frost protection layer/thermal insulation in roads , insulation in buildings, especially suitable for thin-walled thermal insulations, such as for window frames, cement bricks and insulating plasters or other civil engineering applications. Foam glass can also provide very effective fire protection.The material is very advantageous and is being extensively used in construction thses days. This Report basically presents the manufacture, usage, advantages , disadvantages and other engineering aspects of Foam glass.

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Introduction A foam is a substance that is formed by trapping pockets of gas in a liquid or solid. A bath sponge and the head on a glass of beer are examples of foams. In most foams, the volume of gas is large, with thin films of liquid or solid separating the regions of gas. An important division of solid foams is into closed-cell foams and open-cell foams. In a closed-cell foam, the gas forms discrete pockets, each completely surrounded by the solid material. In an opencell foam, the gas pockets connect with each other. A bath sponge is an example of an opencell foam: water can easily flow through the entire structure, displacing the air. A camping mat is an example of a closed-cell foam: the gas pockets are sealed from each other, and so the mat cannot soak up water. Foams are examples of dispersed media. In general, gas is present in large amount so it will be divided in gas bubbles of many different sizes (the material is polydisperse) separated by liquid regions which may form films, thinner and thinner when the liquid phase is drained out of the system films.[1] When the principal scale is small, i.e. for a very fine foam, this dispersed medium can be considered as a type of colloid. The term foam may also refer to anything that is analogous to such a foam, such as quantum foam, polyurethane foam (foam rubber), XPS foam, Polystyrene, phenolic, or many other manufactured foams. The same concept is used in the process of Foamed glass.

Figure 1. Soap foam bubbles

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Foamed glass The study of thermodynamics in the late 19th century included the heat-transfer properties of materials and led to the concept of thermal insulationthat is, a material that has a relatively low rate of heat transfer. As building atmospheres became more carefully controlled after 1900, more attention was given to the thermal insulation of building enclosures . One of the best insulators is air, and materials that trap air in small units have low heat-transfer rates; wool and foam are excellent examples. The first commercial insulations, in the 1920s, were mineral wools and vegetable-fibreboards; fibreglass wool appeared in 1938. Foamed glass, the first rigid insulating foam, was marketed in the 1930s, and after 1945 a wide variety of plastic foam insulations was developed. Since the 1970s most building codes have set minimum requirements for insulation of building envelopes, and these have proved to be very cost-effective in saving energy. Foamed glass is A light, black, opaque, cellular glass made by adding powdered carbon to crushed glass and firing the mixture which acts as a cellulating agent.These components are mixed, placed in a mold, and then heated to a temperature of approximately 950 oF. During the heating process, the crushed glass turns to a liquid. Decomposition of the cellulating agent will cause the mixture to expand and fill the mold. The mixture creates millions of connected, uniform, closed-cells and form at the end a rigid insulating material. It is widely used as light weight fill material, thermal insulation in roads and buildings, and insulation under the floor slab as well because of its light weight, low parameters of heat conductivity. It is also used in the petroleum and chemical industries as well as underground engineering and military projects for heat insulation, temperature conservation, cold storage and sound insulation.

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Figure 2 Foamed Glass

Production Process Foamglass is produced using an environmentally friendly recycling technology for contaminated and toxic waste ranging from mercury lamps, industrial slag and flyash, PC and TV-tubes, and laminated glass to batteries. The process is based on the concept of transforming finely ground glass powder from different glass sources mixed with an activator like silica carbide into glass foam. In the grinding process heavy metals are separated out and recycled to metal melting plants.

Figure 3 Porous Foamed Glass

The powder is spread on a steel belt conveyor running through high temperature ovens whereby the powder expands about 4 times leaving the oven as a glass foam material. When5

the product leaves the oven it will crack and separate into smaller units due to the temperature shock. Normal grain size will be in the range of 10 60 mm .The production process is free of dust and any harmful gases and does not need water at any stage.

The principles behind this system are very simple: To separate and to clean the waste in fractions for further treatment down the process line. During this process the toxic components are reduced below the detecting limits. In this connection a certificate has been obtained for the material confirming that possible leaching products from a fill will have toxic contents well below normal environmental requirements. Foamed glass generally consists of 8 per cent of glass by volume and 92 per cent gas bubbles.

Figure 4 Processing of Foamed glass

Properties of foamed glass

Waterproof Foamglass insulation is resistant to water and vapour . As an all-glass, 100% closed cell material it retains all the water-resistant properties of glass. Thus there is no moisture6

absorption, no condensation, no swelling of foamglass insulation , and it helps prevent corrosion under insulation.

Non-combustible Foamglass insulation is made of pure glass, and is non-combustible and also non