Thesis (M.Sc.) - Cairo University - Faculty of Science - Department of Inorganic Chemistry

Geopolymers are a class of inorganic polymers formed by the reaction between an alkali and an aluminum silicate source at ambient temperature. These materials have an amorphous 3-dimentional structure that gives them properties making them an appropriate substitute to ordinary portland cement as a binding material, thus, reducing CO emissions and energy expenditures 2 during the cement production. The target of the present study is to share the intensive research efforts that are currently being addressed worldwide for developing a knowledge base about such a new technology, thus, investigating the geopolymers structure, chemistry, characteristics and durability. The present study depended mainly on using some industrial by-products as sources for the needed silica and alumina. The used materials were: Iron and steel industry by-products: Water-cooled blastfurnace steel slag. Air-cooled blastfurnace steel slag. Metakaolin and related industrial wastes: Metakaolin produced by healing kaolin to about 750oC. Grog (by-product of the clay bricks industry). Ground ceramic waste. The alkalies that have been used as activators were: Sodium hydroxide NaOH. Sodium silicate Na SiO. 9 H O. 2 3 2-combinations of sodium hydroxide and sodium silicate. Investigating the alkali-activation of blastfurnace steel slag for geopolymer formation illustrated the following: Inspite of the efficient characteristics of the geopolymer formed upon using 6% NaOH as an activator, yet, the geopolymer derived using 3% NaOH+3%Na SiO could be the optimum 2 3 based on its higher strength and superior durability towards sulfate and acid attack, fire resistance and negligible expansion upon external alkali exposure. 10-15% of the used water-cooled slag could be safely substituted by air-cooled slag without appreciable reduction in the gained strength-particularly upon using 3% NaOH+3% Na 2 SiO as the slag activator

Issued also as CD