An investigation on the effect of vibration on the workability of fresh concrete using a vertical pipe apparatus

Using an apparatus in which fresh concrete is allowed to flow out of a vertical pipe while being vibrated, it is confirmed that under vibration and at low shear rates the material behaves as a Newtonian liquid. Effectiveness of vibration is to be assessed in terms of maximum velocity but there is a threshold amplitude below which, and an upper limiting frequency above which, vibration has no effect. It is shown that fluidity determined by this method correlates with fluidity determined earlier by an entirely different method.