Therefore, workers should vibrate between 5 and 15 seconds to ensure the second phase of consolidation or de-aeration is achieved. Doing so will reduce the amount and size of surface voids including bug holes and in general, improve the overall quality and appearance of the concrete.

Does concrete need to be vibrated?

Why is it Important? Vibrating concrete is critical because by removing air pockets & packing the aggregate particles together, it increases the density and strength of the concrete. Tightly packed particles will result in a stronger, more durable concrete structure.

At what depth should concrete be vibrated?

The vibrator should penetrate at least 6 inches into the previous layer. A cold joint occurs when the newer layer of concrete is poured on an older layer that has set up and hardened enough to prevent the two layers from bonding.