The Effect of Metakaolin in Production of Low Thermal Conductivity Cement Sand Brick

Abstract

The building sector is arguably one of the most resource-intensive industries in the world, accounting for some 38% of global energy consumption. It contributes significantly to total energy and greenhouse gas emissions. It depends highly on equal energy and carbon-intensive supporting industries such as the building material industry of which cement is one of the major components. Cement production significantly impacts anthropogenic carbon dioxide (CO2) emission responsible for global warming, climate change and airborne dust pollution. In order to reduce energy consumption, CO2 emission and environmental pollution, a worthwhile venture would be the production of sustainable green building materials. This study investigates the characteristics and potential of metakaolin as a cement replacement in the production of low thermal cement sand bricks. Different proportions of metakaolin from 0, 5, 10 and 15% were utilized and experimented upon to determine their suitability as a green component while meeting all standard brick requirements. Towards this end, laboratory work involving sieve analysis, compressive strength test, specific gravity test, water absorption, scanning electron microscopy and thermal conductivity test was conducted. Based on the results obtained, the optimum proportion of metakaolin replacement in cement sand bricks making is 15% by virtue of its having the lowest thermal conductivity value of 0.580 W/mK and meeting the standard requirements of 15.6 MPa > 3.5 MPa (ASTM C129-17 for compressive strength), 17.95% < 18% (ASTM C1403-15 for water absorption), and 0.580 W/mK below 1.23 W/mK (ASTM C177-97 for thermal conductivity). It is thus concluded that metakaolin can be a potential cement replacement material in bricks. Its use enhances the thermal insulation property of building envelopes, reduces cement consumption, contributes to the solving of environmental problems and promotes a better environmentally friendly building sector.