The Effect of Burning Time of Pozzolana Southern Libya on the Properties of Concrete

Abstract

Metakaolin is a pozzolanic material produced by thermal activation of kaolin. This research aims to study the effect of temperature and firing time on the pozzolanic properties and reactivity of the resulting material. Two types of raw materials, which are abundantly available in southern Libya, were used: Sebha pozzolan and Tamanhint pozzolan, which were thermally activated inside the oven at temperatures ranging from 500-800 °C for half an hour, an hour, an hour and a half, and two hours. Compressive strength tests were also conducted on concrete mixtures containing metakaolin to study the reactivity of the produced materials. The results showed that the Sebha sample achieved a 10.89% higher compressive strength compared to the Tamanhint sample. It was also shown that thermal activation of kaolin actually starts at one hour, leading to its transformation into effective metakaolin. It was also found that the optimum temperature for thermal activation is 600 °C, as the changes in the chemical composition of these materials were documented using an X-ray fluorescence (XRF) device. Moreover, it was observed that thermally activated metakaolin has a positive and significant effect on improving the compressive strength of concrete mixes.