Archive for November, 2011

“Continuous fiber-reinforced ceramic matrix composites (CMCs) are attractive candidate materials for structural components in military/commercial airframe or engine/turbine components due to their high-temperature mechanical properties. However, currentCMCs have two major limitations that have prevented replacement of current materials, namely (1) very high processing/materials costs and (2) insufficient corrosion resistance under hydrothermal oxidizing conditions. Geopolymers, in whichamorphous/semi-crystalline aluminosilicates are dissolved into an inviscid, highly concentrated alkaline solution, offer an approach for the development of easily and cost-effectively processed matrix materials for alumina fiber composites. This Phase ISTTR proposal is targeted at demonstrating the feasibility of developing a geopolymer-based CMC with appropriate high-temperature performance. Our approach will include chemical design (i.e., aluminosilicate phase selection and solid-solution composition)and thermal processing of geopolymers so as to create, after firing, CMCs at chemical equilibrium (“petromimetics”) that, too, have more refractory behavior than current geopolymer systems. What is envisioned is a hybridization of present glass-ceramicand geopolymer processing. The work will establish a chemical processing and design/microstructure/property database for this relatively new class of materials, which will enable functional CMC design. Specifically, the role of a highly doped andreactive intermediate gel phase on properties of the final geopolymer will be studied. Cost-effective processing routes for CMCs with adequate high-temperature mechanical properties are attractive to a variety of applications where high-temperaturemechanical performance is required. The use of CMCs in aircraft or stationary engines and turbines have the potential to raise operating temperatures which will result in a significant step up in efficiency than is possible through marginal improvementsusing currently used materials such as nickel-based superalloys.

Source: SBIR.gov

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Edited by J L Provis and J S J van Deventer, University of Melbourne, Australia
– discusses the synthesis and characterisation of geopolymers with chapters covering fly ash chemistry and inorganic polymer cements
– assesses the application and commercialisation of geopolymers with particular focus on applications in waste management
– reviews the latest research on and applications of these highly important materials

A geopolymer is a solid aluminosilicate material usually formed by alkali hydroxide or alkali silicate activation of a solid precursor such as coal fly ash, calcined clay and/or metallurgical slag. Today the primary application of geopolymer technology is in the development of reduced-CO2 construction materials as an alternative to Portland-based cements. Geopolymers: structure, processing, properties and industrial applications reviews the latest research on and applications of these highly important materials.

Part one discusses the synthesis and characterisation of geopolymers with chapters on topics such as fly ash chemistry and inorganic polymer cements, geopolymer precursor design, nanostructure/microstructure of metakaolin and fly ash geopolymers, and geopolymer synthesis kinetics. Part two reviews the manufacture and properties of geopolymers including accelerated ageing of geopolymers, chemical durability, engineering properties of geopolymer concrete, producing fire and heat-resistant geopolymers, utilisation of mining wastes and thermal properties of geopolymers. Part three covers applications of geopolymers with coverage of topics such as commercialisation of geopolymers for construction, as well as applications in waste management.

With its distinguished editors and international team of contributors, Geopolymers: structure, processing, properties and industrial applications is a standard reference for scientists and engineers in industry and the academic sector, including practitioners in the cement and concrete industry as well as those involved in waste reduction and disposal.

Source: Research and Markets.com

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The geopolymer has been prepared from fly ash, metakaolin and Quartz sand, by using the liquid sodium silicate as structural template and sodium hydroxide solution as activator. The effect of glass fiber on the properties of the geopolymer has been studied.

Source: Scientific.Net

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The contribution of ordinary portland cement (OPC) production worldwide to greenhouse gas emissions is estimated to be approximately 1.35 billion tons annually or approximately 7% of the total greenhouse gas emissions to the earth’s atmosphere. Also, it has been reported that many concrete structures, especially those built in corrosive environments, start to deteriorate after 20 to 30 years, even though they have been designed for more than 50 years of service life.

Source: Academia.edu

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PowerPile Expanding Polymer Pillar

PowerPile Expanding Polymer Pillar

The most significant benefit for environment is the PowerPile method’s ability to solve the settlement problem economically, which was impossible with traditional methods. Repair of houses on thick clay areas would have been more expensive than the value of house and therefore the buildings were unrepairable and unlivable house is always a environmental problem.

Firm and elastic geopolymer was tested on test sites and followed in three and five year time frames. The polymer didn’t change it shape, although some color variation were noticed. When analyzing water dissolving there were no significant remnants in water.

Hardened geopolymer is rigid and maintains its charasteristics in water with normal detergents, brines, acids or bases. Only very strong acids, like concentrated nitric acid and concentrated sulphuric acid might damage geopolymer. Polymer doesn’t react with mold or fungus nor does it decay or change it shape. Insects and rodents don’t eat geopolymer.

When compared to traditional piling worksite PowerPile worksite environmental effect is minimal. The time used is very short, installation equipment lighter and traffic minimal. The process is dustless and silent.

Source: PowerPile

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Uretek’s worldwide experience in the maintenance of roads, highways and freeways ensures fast unobtrusive and low cost solutions for the remediation of problems arising from deteriorated sub-base.

Uretek strengthens soil, fills voids, re-seals the soil under culverts, reseals the soil around broken
culverts and pipes, and re-levels concrete in a fraction of the time taken by alternate methods—and we do it at times least inconvenient to road owners and users.

Uretek’s Worldwide Experience
The Uretek Method was invented in Finland in some 35 years ago, and is now found in 90 countries
around the world, including India.

Strengthen foundation ground
The Uretek Deep Injection process consolidates the ground and increases its bearing strength, resulting in long-term foundation support. Deep Injection is a permanent, fast and cost-effective
alternative to piling and underpinning.

Source: http://www.uretek.in/information/Uretek%20Information%20Sheet%20-%20Roads%20&%20Highways.pdf

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China is one of the big coal production countries as well as USA. It is of great benefit that coal gangues are very rich in kaolin and discarded as huge amount of pyramid-like piles over so many years. It is said the piles are nearly 1500 in number. The total amount is estimated 3.4 billion tons and is increasing at a rate of 1.7 billion tons per annum… Application of coal gangues to geopolymers in China, where Portland cement production is increasing at an enormous rate now, will reduce tremendous amount of carbon dioxide emissions.

Source: Google Books

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