Concrete/Grout Strength for Foundation:
When concrete is poured in deep foundation special requirement for workability is important. We know in deep foundation like piling work, one of the most popular pouring techniques is through funnel hopper.
The compressive strength specified minimum value in IBC-2009 are as follows:
Concrete poured through funnel hopper from top of foundation element, should be proportioned such that proper cohesiveness of the mix is achieved.
The minimum slump recommended as per IBC is 102mm equivalent to 4 inches.
There have also a maximum limit too, that is less than 204.mm equivalent 8 inch. In some cases grout has to pump, the mix should be designed to have pump-able work ability. we already have discussed about pump-able concrete mix.
Note: In deep foundation like piling work, one of the most popular concrete pouring techniques is through funnel hopper.