Abstract
Blending supplementary cementitious materials with portland cement is one of the current strategies for producing more eco-efficient binders by lowering the energy consumption and CO2 emissions intrinsic to OPC manufacture. The effect of such additions on heat of hydration and energy performance is a subject of particular interest, for higher heat may reduce the service life of a concrete structure, whilst energy consumption per tonne of binder or megapascal may prove not to be energy-efficient. This paper explores the energy performance of granite sludge (GS) as an active addition to clinker and the effect of this by-product on heat of hydration and eco-efficiency. The findings show that maximum heating and total heat released are lower in the additioned than in the conventional material, with the difference widening at higher replacement ratios. At 35% GS, maximum heating was 36% lower than in OPC and total heat released 24% lower. Optimal energy performance is observed at ratios of 15% to 30% (both inclusive), with the experimental materials requiring less energy (−1.6 kW·h·t−1/MPa – 0.8 kW·h·t−1/MPa) than ordinary cement per megapascal (MPa) of strength. Cements with 15% to 30% granite sludge are consequently eco-efficient. With 15% GS they can be classified as ordinary (>270 J/g at 41 h), with 20% to 30% as low heat cements (<270 J/g at 41 h) and with 35% as very low heat cements (<220 J/g at 41 h).
Submitted Version (
Free)
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call