Creep is defined as a phenomenon in which strain in a solid slowly increases under constant stress. It is a viscous deformation with some delayed elastic deformation included. Creep in post crack stage is of interest for fibre reinforced concrete at
W. Kusterle (H)
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P. Serna et al. (eds.), Creep Behaviour in Cracked Sections of Fibre Reinforced Concrete, RILEM Bookseries 14,
different load levels and pre-deformation. Data is missing for discrete fibres produced of different materials and with different geometry at low dosage in contact with a cement matrix at different humidity and temperature. Creep in tension of fibre reinforced concrete may be investigated in direct tension tests, in tests on beams and in test on panels. In this paper flexural creep tests on beams are discussed. Tests on beams are usually used for determining the values for design. Therefore it makes sense to use the same or similar testing procedures for creep investigations, too. Direct tensile tests would be more precise, but are much more complicated to perform, there use is limited to research purposes. Tests on panels are more favourable to show the positive effect of fibres, but are one more step from the needed design values. Panels with continuous support along all four sides will have problems with external and internal friction, especially in the case of long term tests at low load level. However, it must be kept in mind, that flexural tests are sensitive to specimen preparation, curing and humidity during testing, resulting in high scatter of the results. The load-deflection graph is instable after the first crack and often influenced by the loading speed and the used testing machine.