Prediction of the dynamic modulus of elasticity of concrete under different loading conditions

This investigation describes the estimation of the modulus of elasticity of plain and reinforced concrete cylinders subjected to axial loading. Several plain and reinforced concrete cylinders were prepared. The fundamental flexural frequency of the concrete cylinders for different boundary conditions was measured and then the dynamic modulus of elasticity was calculated. The influence of axial compressive stress on the dynamic modulus was also considered. A data acquisition system was designed to measure longitudinal as well as flexural frequencies of the concrete specimens with variable axial loading. Furthermore, the effect of the embedded steel bars in the concrete cylinders on the dynamic modulus was investigated. For the concrete mix design utilized in this study, no significant difference between the dynamic and the static moduli of elasticity was observed. This was contrary to the perceived general notion of having the dynamic modulus considerably higher than the static modulus. Discrepancies between the static and dynamic moduli of elasticity for the tested plain concrete cylinders may be attributed to possible formation of micro cracks.Corresponding Author: Dr. Ala Malaikah, College of Engineering, King Saud University, P.O. Box 800, Riyadh 11421, Saudi Arabia. Email: malaikah@ksu.edu.s