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- Bauordnungsrefcht (1)
- Brandschutz (1)
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Der Artikel behandelt die Nachweisführung zum Feuerwiderstand von Mauerwerks-Bauteilen. Es werden die möglichen bauaufsichtlichen Anforderungen an Standsicherheit und/oder Raumabschluss im Brandfall, die mögliche Nachweisführung über Bauarten als technische Baubestimmungen oder Bauarten mit Anwendbarkeitsnachweis, die Zuordnung der bauaufsichtlichen Anforderungen zu den Leistungsangaben in den Nachweisen und die Grundlagen der brandschutztechnischen Bemessung von Mauerwerksbauteilen diskutiert.
A reinforcement of concrete structures is needed because of the low tensile strength of concrete. Corrosion of the usually used steel reinforcments cause issues during time. Therfore, alternative reinforcements produced from non-corosive materials - like polymer fibers - become more interesting. A polymer fiber has to reach high mechanical properties and a good bonding ability to concrete. Both properties can be influenced by the selection of polymer and the used production process. Two polymers, polypropylene and aliphatic polyketone are tested within this study. First mono-material fibers of each material are produced and tested, later the materials are combined in a core-shell fiber. All fibers are produced by standard extrusion or coextrusion and a later drawing process. The mechanical properties are determined by tensile tests. The calculation of interfacial shear strength from single fiber pull-out tests allows an evaluation of the bonding ability. Additionally, fiber surface before and after pull-out is examined using reflected light microscopy. Contact angle measurements are done to evaluate possible influences of the surface energy and polarity. Density measurements are used to compare weight potential of the different mono-material and core-shell fibers. The results show good mechanical properties for all fiber materials. The interfacial shear strength is ≈ 2-3 times higher for fibers with polyketone compared to the ones with polypropylene at the fibers surface, which can be explained by higher surface energy and polarity of the polyketone compared to polypropylene and different surface deformation during pull-out. Lower densities are reached by fibers containing polypropylene.