Mechanism of hydration of the metakaolin-lime-water system

The reaction kinetics of a mixture of metakaolin and lime (calcium hydroxide) in water at 60 degreesC has been investigated using thermal analysis. The numerical results have been used to determine the nature of the reaction. It is shown that, on the whole, this pozzolanic reaction is diffusion controlled and can be represented by the Jander diffusion equation. The paper discusses a new rapid method for monitoring the reaction, utilizing a microwave oven to stop it at any desired reaction time. The nature and quantity of the reaction products were determined by differential thermal analysis (DTA), thermogravimetry (TG) and X-ray diffraction (XRD). (C) 2001 Elsevier Science Ltd. All rights reserved.