Abstract

• Kaolinite clay has been modified with thermal treatment for application as pozzolanic material in cement. The thermal analysis of kaolinite has been characterized by using Thermogravimetric/ Differential Thermal Analysis (TG/DTA). In the result of TG-DTA, the endothermic peak (dehydroxylation temperature) has been observed at 542.95ºC. Kaolinite clay has been heat-treated at three different temperatures; 600 ºC, 700 ºC, and 800 ºC for two hours duration each. The phase analysis of kaolinite samples has been analysed by using X-ray Diffraction technique (XRD). The pozzolanic activity of metakaolinite samples has been revealed by strength activity index (SAI). Finally, the elemental content of the resultant metakaolinite sample has been analysed by Energy Dispersive X-ray Fluorescence (EDXRF). The XRD result has revealed that the original crystalline microstructure of kaolinite has transformed into an amorphous one after thermal treatment. According to EDXRF analysis, it has been found that kaolinite clay is suitable to be used as cement replacement. Based on the XRD and SAI test results obtained, it is revealed that metakaolinite produced from the treated temperature at 700 ºC for 2 hours was adopted as pozzolanic material for natural pozzolan production.