Compaction to freshly placed concrete piles 

In general practice, reliance is placed on the self-compaction of particularly designed concrete mixes to achieve adequate compaction. The use of vibrating devices such as poker vibrators is rarely adopted for the compaction of concrete piles. As a matter of fact, other than the consideration of the impracticality in using vibrating device in long piles, there is serious concern about possible occurrence of aggregate interlock that poses difficulty at the time of casing extraction. In the worst scenarios, temporary casings together with reinforcement cages are extracted at the time of the lifting up of pile casings. This is another reason that accounts for not using vibrating machines for piles with casing extraction.