Thermal characteristics of metakaolin-blended hollow sandcrete blocks

Abstract

Sand-cement hollow blocks are widely applied in building construction in most countries. Attempt to  lower the high costs of the material constituents, as well as the desire to enhance properties, has led to the substitution of the constituents with different admixtures. Adding admixtures to most cementitious materials often affects their thermophysical properties. One of the commonly used admixtures is metakaolin. This study investigates the thermal characteristics of hollow sandcrete blocks produced with metakaolin-blended cement. The replacement of cement with etakaolin is varied up to 30% by volume in a step of 5%. The results show increasing heat transfer rate, heat energy storing capacity and thermal mass with the mekaolin content. Time-response properties such as thermal admittance and thermal effusivity rise while most of the insulating properties reduce with increasing metakaolin substitution. The results show the potential use of metakaolin-based blocks for building applications should be with caution.