Relaxation Behavior of Concrete under Sustained Uniaxial Compressive Deformation
Publication: Journal of Materials in Civil Engineering
Volume 28, Issue 6
Abstract
An experimental study that investigates the nonlinear stress relaxation behavior of concrete under sustained strains is presented. Reinforced concrete structures experience both creep and relaxation during their service life. While the creep behavior of concrete has been widely investigated, very little is known regarding its relaxation behavior. This investigation includes testing of concrete cylinders under sustained uniaxial compressive strains. The tests are conducted at two different ages of the concrete to highlight the influence of shrinkage and aging on the behavior. A rigid displacement-control hydraulic system that allows testing of concrete cylinders under sustained strains with monitoring of the stress relaxation with time is used. The sustained strain levels correspond to initial stress levels of 35 and 50% of the compressive strength for one set of testing, and to stress levels of 30 and 60% in the other set. For better understanding of the behavior, the relaxation tests are also accompanied with creep tests under similar levels of sustained loading.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The author would like to thank Dr. Zhen-Tian Chang for his help in conducting the experimental work and collecting the data.
References
AS (Standards Association of Australia). (1997). “Methods of testing concrete. Method 17: Determination of the static chord modulus of elasticity and Poisson’s ratio of concrete specimens.” AS1012.17, Sydney, Australia.
Balevičius, R., and Dulinskas, E. (2010). “On the prediction of non-linear creep strains.” J. Civ. Eng. Manage., 16(3), 382–386.
Bažant, Z. P. (1988). Mathematical modeling of creep and shrinkage of concrete, Wiley, New York.
Bažant, Z. P., Hubler, M. H., and Jirasek, M. (2013). “Improved estimation of long-term relaxation function from compliance function of aging concrete.” J. Eng. Mech., 146–152.
Bažant, Z. P., and Kim, J. K. (1991). “Improved prediction model for time-dependent deformations of concrete: Part 2—Basic creep.” Mater. Struct., 24(6), 409–421.
Bažant, Z. P., and Kim, S. S. (1979). “Approximate relaxation function for concrete.” J. Struct. Div., 105(12), 2695–2705.
BRE (Building Research Establishment). (1997). Design of normal concrete mixes, 2nd Ed., Watford, U.K.
Brueller, O. S., and Steiner, H. (1993). “Creep-based characterization of nonlinear relaxation behavior of plastics.” Polym. Eng. Sci., 33(21), 1400–1403.
CEB-FIP. (1990). “Design code.” Comité Euro-International du Beton, Thomas Telford House, London.
CEN (European Committee for Standardization). (2004). “Design of concrete structures. General rules and rules for buildings.”, Brussels, Belgium.
Fernández Ruiz, M., Muttoni, A., and Gambarova, P. G. (2007). “Relationship between nonlinear creep and cracking of concrete under uniaxial compression.” J. Adv. Concr. Technol., 5(3), 383–393.
Findley, W. N., Lai, J. S., and Onran, K. (1976). Creep and relaxation of nonlinear viscoelastic materials (with an introduction to linear viscoelasticity), North-Holland, Amsterdam, Netherlands.
Gilbert, R. I. (1988). Time effects in concrete structures, Elsevier Science Publishers B.V., Amsterdam, Netherlands.
Hamed, E. (2012). “Nonlinear creep response of reinforced concrete beams.” J. Mech. Mater. Struct., 7(5), 435–460.
Hamed, E. (2014). “Modelling of creep in continuous RC beams under high levels of sustained loading.” Mech. Time-Dependent Mater., 18(3), 589–609.
Hamed, E. (2015). “Nonlinear creep effects in concrete under uniaxial compression.” Mag. Concr. Res., 67(16), 876–884.
Neville, A. M., and Dilger, W. H. (1970). Creep of concrete: Plain, reinforced, and prestressed, North-Holland, Amsterdam, Netherlands.
Omar, M., Loukili, A., Pijaudier-Cabot, G., and Le Pape, Y. (2009). “Creep-damage coupled effects: Experimental investigation on bending beams with various sizes.” J. Mater. Civ. Eng., 65–72.
Oza, A., Vanderby, R., and Lakes, R. S. (2003). “Interrelation of creep and relaxation for nonlinearly viscoelastic materials: Application to ligament and metal.” Rheologica Acta, 42(6), 557–568.
Smadi, M. M., Floyd, O. S., and Arthur, H. N. (1985). “High-, medium-, and low-strength concretes subject to sustained overloads-strains, strengths, and failure mechanisms.” J. Am. Concr. Inst., 82(5), 657–664.
Thomas, D. P. K., and Monteiro, P. J. M. (1986). “Stress relaxation: Comparison of measured and computed values.” J. Am. Concr. Inst., 83(3), 432–437.
Touati, D., and Cederbaum, G. (1997). “Stress relaxation of nonlinear thermoviscoelastic materials predicted from known creep.” Mech. Time-Dependent Mater., 1(3), 321–330.
Information & Authors
Information
Published In
Journal of Materials in Civil Engineering
Volume 28 • Issue 6 • June 2016
Copyright
© 2016 American Society of Civil Engineers.
History
Received: Aug 20, 2015
Accepted: Nov 16, 2015
Published online: Jan 21, 2016
Published in print: Jun 1, 2016
Discussion open until: Jun 21, 2016
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.