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Einfluss der Art grober Gesteinskörnung auf Struktur und Eigenschaften von ultrahochfestem Beton - Abschlussbericht in Langfassung
Citation Link: https://doi.org/10.15480/882.18537
Publikationstyp
Report
Date Issued
2026
Sprache
German
Author(s)
TORE-DOI
Citation
Technische Universität Hamburg (2026)
Peer Reviewed
false
The addition of coarse aggregate is one possibility to lower the cement content of ultra-high strength concrete (UHPC). Within the research project an UHPC with a maximum grain size of 0.5 mm was varied with 30 vol.-% of coarse aggregate, with a grain size of 5-8 mm. 16 different rock types were added to the fine-grained reference mixture. The rock types cover most of the high strength rocks available in Germany. The rock and the UHPC specimens were examined under different aspects. Both the mechanical behaviour, as the structural and chemical properties were determined. As the main results it can be stated, that not only basalt, but a lot of rock types can be used to produce UHPC, even if the addition of coarse aggregates decrease the strength of all specimens in comparison to the original mixture. Basalt and other fine-grained vulcanic rocks are useful, but also coarse-grained plutonic granite and metamorphic granulite and gneiss. Also with dense sedimentary limestone (Massenkalk), UHPC can be produced. Coarse-grained metamorphic marble, sandstone (also with very high strength), and the sandstone-like greywacke, and metamorphic amphibolite were not successful. Dolomite and the examined quarzite resulted in somehow inconsistent strength values. There is a strong linear correlation of the rock and the UHPC compressive strength. There is no threshod value of the rock strength, resulting in a decrease of the UHPC strength, but the lower the rock strength, the lower is the UHPC strength. A correlation between the typical grain size of the rock and the UHPC strength is not visible. In no case, also with very high spatial analytical resolution, a chemical reaction was visible between the minerals of the rocks and the cement matrix. It seems, that the UHPC ist too dry, after short time, to get chemical reactions between the rock grains and the binder matrix. All rock types were very well embedded in the cement matrix. They are great differences in the coarseness of the grain surfaces. Together with differences in the porosity of the rocks this resulted in effects on UHPC workability.
Subjects
ultra-high strength concrete
coarse aggregate
rock type
strength
rupture energy
modulus of elasticity
DDC Class
690: Building, Construction
Funding Organisations
More Funding Information
Projektnummer 506665616
Publication version
publishedVersion
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Bericht_Langfassung UHFB Einfluss grober Gesteinskörnung.pdf
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