Maliqi, V., Daneshvar, D., Liberto, T., Reiter, G., Schichl, H., Kirnbauer, J., Robisson, A., & Stöllinger, W. (2022). UHPC Made with Recycled UHPC and Optimized with AI – an Infinite Reusability? In EMI Book of Abstract (pp. 357–357).
E207-01 - Forschungsbereich Baustofflehre und Werkstofftechnologie
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Published in:
EMI Book of Abstract
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Date (published):
2-Jun-2022
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Event name:
Engineering Mechanics Institute Conference (EMI-2022)
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Event date:
31-May-2022 - 3-Jun-2022
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Event place:
United States of America (the)
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Number of Pages:
1
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Keywords:
UHPC; Recycled Concrete; Mechanical testing; SAOS (small oscillatory rheology); AI
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Abstract:
Ultra-high performance concrete (UHPC) is designed to minimize water-to-binder ratio and maximize strength. This is done through the optimization of packing of all solids in the mixture, as well as the use of superplasticizer. In this study, we use recycled UHPC (freshly milled) to design a more sustainable UHPC, where the recycled UHPC is used to replace the sand (D50=320 μm), the quartz powder (D50=24 μm) and the cement itself (D50=12 μm).
Results show that recycled concrete can fully replace the sand without compromising the 1-D, 7-D and 28-D strengths. The quartz powder can also be replaced by recycled UHPC, either fully, with a drop of 28-D compressive
strength by 10 w%, or by half, without any drop in compressive strength. Lastly, and more importantly, replacing the cement with recycled UHPC by 10 w% results in a negligible 28-D compressive strength loss. Replacing cement at a rate of 50 w% results in a drop of strength by 30 %, from 121 MPa to 86 MPa. Surprisingly, when replacing 100 % of the cement with recycled concrete, the 28-D compressive strength still reaches 23 MPa. These results can at least partially be explained by the freshly milled reactivity of the recycled UHPC powder, measured by oscillatory rheology.
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Research Areas:
Materials Characterization: 50% Sustainable Production and Technologies: 50%