A Quantitative Evaluation of Energy Transfer of a Concrete Vibrator

Using vibration to consolidate concrete is a standard task when placing normal concrete, and dates back to the early 1900s. Since then, concrete vibrators have been optimized to provide efficient consolidation, which includes an increase in their vibration frequency up to 200 Hz. On the other hand, compared to the concrete of the early 1900s, modern concrete has also been improved by reducing the proportion of water content. Both have been changed, but the vibration energy transfer has not been quantitatively evaluated lately for the updated vibrators and modern concrete. Herein, the attenuation of concrete, assuming a cylindrical wavefront and exponential decay for P-wave propagation, is measured and quantified. As a result, it can be concluded that the attenuation coefficient of modern concrete is distributed from 1 to 3 [m.sup.-1]. The notional power density, the maximum vibration energy imposed by a conventional vibrator, is 100 to 300 W/m (3), excluding the instability of near-field liquefaction. Keywords: attenuation; consolidation; rheology; vibrator.