THE EFFECTIVENESS OF RE-VIBRATION ON THE BLEEDING AND DURABILITY OF CONCRETE

Abstract

Re-vibration method applied to fresh concrete is vibration again at intervals after initial vibration of concrete placed.
In the prestressed concrete composition, re-vibration is doing by experience at actual construction site due to lack of knowledge of optimum timing and vibration time. The present study aims to clear the effect of re-vibration by difference of re-vibration method. From the experimental result, increase in compressive strength and resistance of concrete with re-vibration in any concrete composite was confirmed. Timing of re-vibration was found effective in increasing the concrete quality to a value of N＝100mm（N：fresh concrete deformability index value）. Especially, effect of re-vibration was greater for concretes using blast furnace slag and fly ash in comparison with early strength cement. Re-vibration was found as effective means for improving concrete durability.