Influence of Amorphous Silica in Metakaolin on the Compressive Strength and Pozzolanic Reaction of Blended Cement Paste

Abstract

The aim of this study is to determine the percent by weight of amorphous silica in metakaolin using X-ray diffraction method.This factor affects the compressive strength and degree of pozzolanic reaction. Kaolin was burned at different temperatures of 600 700 and 800 c. Burning periods were varied among 4 6 and 8 hr.Metakaolin and sand were ground to have their particle size close to that of Portland cement. They were then used as a direct replacementof Portland cement Type I at 20 percent by weight of binder. A water to binder ratio of 0.42 was used for all cement paste mixture. Results from X-ray diffraction show that the metakaolin burned at 600 ํc for 4 hr. had the most amorphous silica.The result show that the percent by weight of amorphous silica contents affects compressive strength and degree of pozzolanic reaction in blended cement paste