Geo Polymerization of Kaolin and Metakaolin Incorporating NaOH and High Calcium Ash

  •  Nafeth Abdel Hadi    


This research work aims to investigate the possibility to produce Ordinary Portland Cement free construction materials depending on the reactivity of high alkali liquids or solids with rich silica-alumina clay through geo polymerization process. Different mixtures of kaolin, metakaolin, bituminous limestone ash and NaOH were prepared and molded with different ratios. Standard cylindrical samples were prepared from each mixture and cured at ambient laboratory temperature for 28 days to investigate their physical and mechanical properties.

The unconfined compressive strength results of Kaolin-NaOH mixtures have ranged from 19 to 30 kg/cm2 after 24 hours. The unconfined compressive strength results of kaolin ash mixtures have ranged from 23 to 36 kg/cm2 at 28 days. The unconfined compressive strength results of ash-metakaolin mixtures have ranged from 32 to 56 kg/cm2 at 28 days.

Kaolin-NaOH samples revealed various degrees of efflorescence when subjected to wetting and drying conditions, on the other hand, ash –kaolin samples showed efflorescence free surfaces and increasing of strength with increasing the curing time.

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