Concrete used for pile construction is typically a high-slump, self-compacting mix designed for easy flow around the reinforcement cage. Its self-compacting nature eliminates the need for vibrators, as the concrete is already formulated to achieve optimal compaction without additional external forces.
Furthermore, the process of pouring concrete into piles inherently provides compaction through the energy generated by free-falling. This natural compaction mechanism is sufficient for achieving the desired density and strength in the pile concrete.
Using vibrators in pile concreting can be counterproductive. The vibration can force the concrete to compact against the sides of the casing, hindering the subsequent lifting of the casing after the concrete has set. This can lead to difficulties in removing the casing, potential damage to the pile, and increased construction time and costs.
As referenced in GEO (1996), the combination of high-slump, self-compacting concrete and the free-falling compaction method provides a reliable and efficient approach to pile construction. By avoiding the use of vibrators, engineers can ensure the smooth removal of casings and maintain the integrity of the pile structure.