Ghent University. Faculty of Engineering and Architecture
Abstract
Although concrete is a durable material, it has a big impact on the environment due to its high production volumes. This impact is mostly related to the consumption of virgin raw materials, the production of waste and the emission of carbon dioxide. The aim of this study was to move towards a high value recycling of construction and demolition waste. Inspired by the cradle-to-cradle concept, Completely Recyclable Concrete (CRC) is designed as a raw material for clinker production, without the need for ingredient adjustments.
Several CRC compositions were designed after carefully selecting suitable raw materials (e.g. fly ash, porphyry aggregates, copper slag and calcium aluminate cement). The quality and durability of these CRC mixtures was assessed with special attention to the possible applications of copper slag and the deceleration of the fast setting that resulted from the combination of calcium aluminate cement and blast furnace slag cement. The CRC clinker and cement quality were studied in depth by in situ and ex situ XRD/Rietveld analysis, light microscopy and thermal analysis. Also the applicability of an existing OPC hydration model was verified. Finally, the sustainability of the CRC concept was verified using Life Cycle Assessment
