Surfaces Preparation for Pile Heads:
The weak concrete layer on the pile head top face needs to be broken until solid/sound concrete is reached. Remove the weak concrete laitance by wire brushing the concrete surface using clear portable water.

Pile Head Treatment:
Pile head top face needs to be repaired with high-strength cementitious grout. The waterproofing membrane should be extended over both pile head sides and top face, up to the reinforcing bars limit. 
Pour 30mm of high strength epoxy grout on top and side of pile head to seal the face and side of pile.