Kaolin Case Study

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T.Ramlochan, et al. (2003) the expansive behaviors of heat cured mortars containing pozzolans and slag was investigated by the authors. In almost all the mortars, the addition of any amount of pozzolans and slag to the mixture usually reduced the onset of expansion, the rate of expansion, and long-term expansion. However, the efficiency of a particular pozzolan (or) slag in controlling expansion may depend on its Al2O3 content. Metakaolin, which contains a higher amount of reactive Al2O3, was the most effective at controlling expansion at relatively low cement replacement levels. Slag and fly ash which are also sources of Al2O3 were also effective at suppressing expansion at higher replacement levels. Silica fume was less effective at controlling …show more content…

For comparison, a commercial MK of high purity was used and the strength development of Metakaolin concrete was evaluated using the K - value (efficiency factor). The produced Metakaolin as well as the commercial one imparted similar behaviour with respect to the concrete strength. Both conventional and commercial Metakaolins demonstrate very high K-values (close to 3.0 at 28 days) and are depicted as HR pozzolanic materials that may lead towards concrete production with an exceptional …show more content…

The Metakaolins examined appear to have a catalyzing effect on cement hydration, leading to acceleration in the reaction rates, an increased in cumulative heat evolved during early hydration and for some cements apparently an increased intensity in heat evolved during certain periods of each hydration. The surface area of the Metakaolin also seems to influence these early hydration behaviors, with the higher surface area material producing a greater rate of heat evolution, greater cumulative heat, and greater intensity during early hydration. It is proposed that the Metakaolin may act to enhance dissolution of cementitious phases and or by providing nucleation, in addition to increasing the solubilized aluminium in the system at early

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