Utilization potential of fly ash together with silica fume in autoclaved aerated concrete production

The increase in the number of thermal power plants has led to the production of an increasing amount of fly ash that causes high environmental impact in Turkey. Many researchers around the world are looking at methods of gainful utilization and disposal of fly ash. However, the construction materials industry is the most suitable way to mass consumption of the fly ash waste. In this study, the utilization potential of fly ash and silica fume in Autoclaved Aerated Concrete (AAC) production were investigated. Optimum fly ash/cement ratio was determined, and this composition was improved by the silica fume addition. Strength-Microstructure relations of the products were investigated. Crystalline C-S-H phases of Tobermorite and Xonotlite were developed after autoclaving at 4 bar. Silica fume addition was found to be useful for the prevention of the ettringite phase in the product. Silica fume addition improved the hydrothermal conditions during the autoclaving of the mixtures.