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On The Chemo-Physical and Microstructural Properties of Rice Husk Ash and Its Performance in Cement Mixtures

Gholizadeh Vayghan, Asghar | 2010

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 41178 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Khalu, Alireza
  7. Abstract:
  8. Growing production of cement and concrete in developing countries like Iran in addition to high amounts of energy consumption and pollutants formation through production of cement has motivated researchers to partially replace it with suitable additive materials. In this study, the chemo-physical and microstructural properties of rice husk ash as an agricultural waste and its performance in cement mixtures as a pozzolan is experimantally investigated. Parameters influencing the pozzolanic properties of this material that are studied include the effect of acid leaching before pyro-processing, heating rate, retention time, and grinding time. Additionally, this material is compared with other artificial pozzolanas such as silica fume, fly ash class C and F and zeolite regarding lime reactivity and strength activity. What is more, nanosilica is synthesized from rice husk ash by precipitation method. Experimental methods include X-ray diffraction and fluorescence, scanning electron microscope, porosity and specific surface area measurement by BET test method, electrical conductivity and pH measurement, determination of water demand of blended cement, flow and compressive strength measurement. The results show that hydrochloric acid pretreatment results in elimination of deleterious alkalis and facilitates volatilization of organic matter even in low temperatures and retention times and the yield product will be of much better performance. Acid leaching highly improves lime reactivity and enhances pozzolanic performance of the ash. With hydrochloric acid pretreatment the pozzolanic performance of the yield ash is maintained and even improved in sudden burning, prolonged burning and higher temperatures. Rice husk can be converted to reactive pozzolans with higher performance compared to fly ash, zeolite and even silica fume
  9. Keywords:
  10. Environmental Pollutant ; Pickling ; Nanosilica ; Agricultural Wastes ; Rice Husk Ash ; Pozzolanic Performance

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