Determination of E -Modulus of Young Concrete with Nondestructive Method

This paper is concerned with the determination of the modulus of elasticity of concrete at very early ages by means of a nondestructive method. The method covers measurements of the dynamic resonance frequency on concrete prisms with fast Fourier transform (FFT) analyzer. At a known resonance frequency the dynamic E-modulus and the damping coefficient can be calculated. Based entirely on the dynamic test results a simple empirical formula is suggested for prediction of the static modulus of elasticity. Application of the prediction formula for two concrete mixtures showed consistency and good agreement with the static test results. The advantage of the dynamic procedure is that the method enables measurement of progressive changes in the stiffness of the concrete without damaging the specimen, and it gives high quality and consistency in the test results relative to the static method.