Coal ash use as a cement replacement in concrete production

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Ordinary Portland cement (OPC) is the main contributor of concrete CO2 emissions amongst concrete constituents. Use of alternative cementitious materials is highly encouraged to lower environmental footprint of concrete production. Local waste materials could be a feasible approach in terms of economic and environmental sustainability due to local availability. In this study, coal ash waste was used as a Portland cement replacement by 10% and 20% for the production concrete mix concrete mix with 28-day design strength of 45 N/mm2. Developed mixes were tested against various engineering properties including workability, bulk density, compressive strength, sound permeability, thermal conductivity, water permeability and porosity. Results showed that coal ash incorporated mixes had slightly lower slump values with slightly lower fresh density. Hardened properties including bulk density and compressive cube strength were reduced slightly for CA mixes. Other hardened properties showed that CA mixes had more compact structures compared to conventional mix. Therefore, CA mixes showed enhanced sound permeability, thermal conductivity, water permeability and porosity.