Influence of gradual imposition of tensile stresses on associated viscoelastic behaviour

Author(s): Dirk Schlicke, Eva Maria Dorfmann
Paper category: Proceedings
Book title: Proceedings of the 2nd International RILEM/COST Conference on Early Age Cracking and Serviceability in Cement-based Materials and Structures Volume 2
Editor(s): Stéphanie Staquet and Dimitrios Aggelis
ISBN:978-2-35158-200-8
e-ISBN:978-2-35158-198-8
Publisher: RILEM Publications SARL
Publication year: 2017
Pages: 609-614
Total Pages: 6
Language : English

Abstract: The viscoelastic behaviour of concrete has a significant influence on the performance of concrete members. Besides its negative influence on deflections under load impact, the viscoelasticity is supposed to positively reduce the hardening- induced restraint stresses after temperature equalization due to the hereby caused relaxation. Next to other restraint- decreasing influences due to cracking, the outlined relaxation after temperature equalization is an essential assumption for a relatively well-established design practice of structural concrete, namely neglecting the superposition of hardening- induced restraint stresses with later restraint stresses during service life.
However, current experiments with customized restraint frames at Graz University of Technology indicated a very small effect of relaxation of hardening-induced tensile stresses after the hardening phase, see [1]. After temperature equalization only a very small relaxation was determined even if the tensile stress level reached up to 60% of the long term tensile strength. For a better understanding of these experimental observations specific tensile creep studies on hanging specimens under sealed conditions were conducted. In a first step, the effect of slight unloading on relaxation under tension was investigated, as reported in [2]. A subsequent and herewith presented study concentrated on the influence of a gradual imposition of the tensile stresses according to usual stress histories in hardening concrete [3].

Online publication : 2017
Publication type : full_text
Public price (Euros) : 0.00