Metakaolin as a cement replacement material

The production technology of metakaolin to be used as a cement replacement material complying with the European and Egyptian standard specifications is being studied in Egypt. Kaolin quarried from different locations was characterized chemically, mineralogically and its thermal behavior was determined. The sample with highest kaolinite content, lowest in quartz and ferric oxide was chosen for the industrial production of metakaolin. Preliminary investigations were performed on a laboratory scale to define the best conditions for its thermal activation to obtain a product with acceptable pozzolanic reactivity. The mineral was heated in an industrial rotary kiln for 1 hour at 700oC. Replacement of < 10% Portland cement by metakaolin in concrete was found to improve the 28-day compressive strength, the extent of improvement depending on its fineness.

Author: H.Y. Ghorab, H.E.H. Ahmed, A. Tawfik

Section: Concrete

Keywords: cement replacement material, metakaolin, concrete