Foundation, Concrete and Earthquake Engineering

What is Revibration in Concrete Compaction?

We have discussed many aspects of concrete compaction in previous posts. We can recall, we have published several posts about concrete over-vibration, its disadvantage and way to diagnosis over-vibration and its detrimental effects on concrete properties. Here, we will discuss another term revibration.

Notice that we are not leaving any term about concrete and its manufacturing process. Dear reader please stay with us, we will discuss every inch of concrete technology. Now we will catch the right point re-vibration.

We know concrete need to be compacted to expel any air void and cavities. Once we have no way to compact concrete except hand compaction like rodding, ramming and tamping. Now we have mechanical device to compact concrete effectively. The vibrator is the device that is of different type. We have discussed some types of vibrator and some types of the same are coming soon. Degree of vibration depends on the type of vibrator and right application of it. Each vibrator has also a particular field to apply. After application of vibration as compaction effort, there arise some terms like over-vibration, revibration.

Concreting for pavement slab in two layer, separated by reinforcements

Concreting for pavement slab in two layer, separated by reinforcements

Revibration is delayed application of vibration to concrete which has placed and compacted already. Now question is why we should make delay in compaction effort. This condition arises where concrete is placing in layers for a relatively deep member. Where first layer is vibrated and may have hardened partially and application of vibration is transmitted to the underlying layer. In some cases this is done intentionally. 

Vibrating top layer concrete revibrating lower concrete layer in deep concrete mass of a dam
Now question arises what are the consequences of disturbing partially hardened concrete or why revibration is provided intentionally. Yes friends there have some beneficial effects of revibration of concrete. The aggregate particles are get rearranged and voids from either by air or water is removed, thus providing more compacted concrete mass to form a solid concrete of high strength properties. But, when and how should we use this repeating vibration? Dear reader we will find the answer of these questions in the next posts.

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