Application of Impulse Excitation Technique to Investigation of Concrete Damping and Its Changes at Early Ages

Abstract

This paper considers experimental results of internal friction test of concrete blocks using impulse excitation technique. Three concrete blocks (120X80X40mm) have been tested at the ages of 7, 14, 28, 56 and 91 days with the Resonant Frequency Damping Analyzer (RFDA) Basic. Mix proportions of the material were selected according to the ACI method. The material of specimens is assumed to be isotropic, and it was proved that this assumption could be applied in practice. It was shown that damping of concrete reduces with time. The most significant changes occur at very early ages, before 14 days. After that this process slows down, however, it continues with lower rate.