Investigation of the properties of cement stone modified with metakaolin

Abstract

Unfortunately, Portland cement manufacturing generates very high CO2 emissions accounting for around 7% of the total global CO2 emission per annum. Using mineral materials reclaimed from industrial waste to replace cement and natural aggregates is one of the most common environmental impact abatement techniques in concrete industry, Metakaolin is another type of industrial waste generated in the manufacturing process and accumulated in storage places. The annual generation of metakaolin in Lithuania is almost 1000 tones. Metakaolin is obtained via the endothermic reaction of kaolin. The article addresses the effect of waste metakaoline from expanded glass produsing industry on the properties of cement stone. Metakaolin is considered as one of most promising pozzolanic microfiller material in concrete industry. Seven different cement paste mixes containing from 0 % to 30 % of waste metakaoline added by weight of cement were analysed. Physical and mechanical properties of the cement stone was tested at the age of 90 days. Determined that 15 % replacement of cement with waste metakaoline slightly increased the density, the propagation velocity of ultrasonic pulses as well as compressive and bending strengths of cement stone. The test results revealed that waste metakaoline can be used in small amounts to reduce the amount of cement and not to impair physical and mechanical properties of the cement stone.