ABSTRACT
Modern High Performance Concrete (HPC) and Ultra High Performance Concrete (UHPC) are almost ideal brittle materials with outstanding mechanical properties. Effective stiffness or strength of HPC or UHPC strongly depends on material inherent micro- and meso-scale imperfections, e.g. micro-cracks. These effective material properties evolve during the lifetime of the material, and a well-established material characterization is given by the ratios stiffness or strength per number of cycles which can be performed well in the laboratory. In the present approach, we discuss a material characterization technique for effective stiffness based on low-amplitude harmonic excitations with frequencies from 0.1 Hz up to 1 kHz. The samples will be harmonically loaded with a high-performance piezo-electric actuator which is also used for measuring the intrinsic attenuation of the material.
