Title: Stress Relaxation: Comparison of Measured and Computed Values
Author(s): D. Pirtz, K. Thomas, and P. J. M. Monteiro
Publication: Journal Proceedings
Appears on pages(s): 432-437
Keywords: age; concretes; creep properties; residual stress; stress relaxation;stress relaxation tests.
Relaxation tests for two concrete mix designs were performed under automatically controlled conditions. For one of the mixes, the concrete specimens were stressed at the ages of 28, 60, 90, and 180 days and were kept under stress for a reasonably long period of time. At the same time, a comprehensive creep test program was done for the same mix designs. The results were fitted to curves of logarithmic and power expressions; using the Boltzmann ‘s principle of superposition it was possible to compute relaxation values from the creep data. The relaxation experimental results showed that the power function for fitting creep gave much better results for the computation of stress relaxation than the logarithm function.