A note on the effect of frequency on the behaviour of fresh concrete during vibration

Abstract

Summary The behaviour offresh concrete during vibration varies with thefrequency of the vibration applied. For each mix there is a particular frequency at which a drastic change in the acceleration of the mould and the mix takes place during vibration with constant power input. The strongest concrete is produced at this frequency of vibration.

Laboratory Evaluation of the Response of Reinforced Concrete to Internal Vibration, Phase I : Final Report

“…The intial breakdown occurs within the first few seconds of vibration; continued vibration after this will fliiidify the paste and cause the aggregates to move to optimum positions. Maximum compaction is achieved at an optimum frequency of 12,000 cpm (5), (IO), (I7), (19) 1 (22), (23). Vibration at still higher frequencies results in less compaction and possibly leads to the segregation of the mix* Vibration at a frequency higher than 1 2 ,000 cpm substantially reduces the radius of compaction, since the concrete mass becomes fluid before it can "respond" to the rapid displacements which are imparted by such rapid vibration.…”