Description du projet :
Produced at a rate of over 30,000 million metric tons annually, concrete is the most manufactured material in use in the world today. Consequently, its environmental footprint is a matter of significant concern. From a life cycle point of view, recycling is regarded as an effective way to reduce this footprint, as it addresses the phases where the largest part of the environmental impact takes place: material sourcing and end-of-life disposal. Increasing amounts of concrete wastes are being crushed to produce coarse recycled aggregates. However, over 50% of the output from the crushing plants is a fine-sized granular material with a high concentration of residual hydrated cement that finds limited use in new concrete mixtures because it negatively affects their fresh and hardened properties. Considering that cement is the most expensive constituent of concrete, the reactivation of the cementitious capacity of the cement residues in these fines would not only increase the amount of concrete being recycled, but also the economical value being recovered.
This project aims at bringing this recycling pathway closer to practical implementation, bridging remaining scientific and technical knowlege gaps by characterizing: the fresh and hardened performance of mixtures based on reactivated materials obtained from actual concrete fines; the long term strength gain of mixtures; the effect of the high temperature residence time and the cooling rate on the amount of active calcium silicates that remain stable to ambient temperature; the heat evolved during initial hydration, including the effect supplementary additions and of controlled pre-wetting of the reactivated materials; and, the energy requirements of the thermal process.
Research team within HES-SO:
Durée du projet:
01.03.2014 - 01.03.2017
Montant global du projet: 100'000 CHF