ABSTRACT
This paper presents the study of impact of temperature and duration of calcination of metakaolin on compressive strength development of metakaolin incorporated concrete. Superplasticized concrete specimens containing metakaolin (20%) in replacement of cement were characterized. Three commercially available metakaolin samples manufactured at different temperature and duration were studied. Two of three metakaolin mixes gave strength higher than normal concrete (NC) mix on all days. The third metakaolin mix showed strength higher than NC in early days, but at 28 days its compressive strength became equal to that of NC mix and did not show any enhancement in compressive strength after 28 days. The SEM images of 28 days hydrated specimens showed that the microstructure of all metakaolin incorporated concrete specimens were dense with a remarkable presence of calcium alumino silicate hydrates. NC matrix showed a clear presence of Ca(OH)2 which was completely absent in the microstructure of metakaolin incorporated concrete.
