Research on the Phenomenon of Relaxation of Compressed Concrete Elements

Abstract:

This article presents results of research aimed at identifying the phenomenon of stress relaxation in compressed concrete elements. The study used a special test stand, designed and constructed by Dr.Eng. Krzysztof Kaminski which allows permanent strain of cylindrical concrete sample by adjusting force. Cylindrical samples with a diameter of 15 cm and 10.5 cm and a height of 30 cm for the study were used. The samples were made of different classes of concrete. There was also defined the influence of applied tensile stress and the age of the sample on the relaxation phenomenon. The expected result of the research was to obtain relaxation curves of concrete samples with different compressive strength and age. Relaxation of concrete is important for the analysis of bending elements sections, which behavior during the operational phase of the concrete can significantly deviate from the assumed one, causing other than triangular or parabolic distribution of compressive stresses.

• Periodical: Applied Mechanics and Materials (Volume 797)
• Pages: 53-60
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.797.53
• Online since: November 2015
• Authors: Krzysztof Kamiński*, Bartłomiej Ciarkowski
• Keywords: Compressed Concrete Elements, Relaxation, Rheology

References

[1] A. Mitzel: Rheology of Concrete (in Polish), Arkady, Warsaw (1972).

[2] W. Derski, S. Ziemba: Analysis of Rheological Models (in Polish), PWN, Warsaw (1968).

[3] M. Zakrzewski, J. Zawadzki: Strength of Materials, PWN, Warsaw (1983).

[4] W. Osipiuk: Inelastic Deformation and Cracking of Materials (in Polish), Dział Wydawnictw i Poligrafii, Białystok (1999).

[5] A.M. Neville, Properties of Concrete (in Polish), fourth edition, Polski Cement Sp. z o. o., Cracow, ISBN-83-913000-0-5.

[6] A.D. Ross: Creep of concrete under variable stress. J Amer. Concr. Inst., 54, s 739-758, March (1958).

[7] Garofalo F.: Fundamentals of Creep and Creep Rupture in Metals, The MacMilan Company, New York (1965).

[8] EN 12390-2: 2001 Concrete testing - Part 2: Making and maintenance of samples for strength testing.

[9] PN-B-03264: 2002, Concrete, reinforced and prestressed structures. Static calculations and design. (in Polish).