small amount of black sealant (Cheadle Hulme SK8)

We need a small amount of black waterproof sealant to fill the gap between the bricks and the 2 new black waste-water pipes from our washing machine and dishwasher that we've recently moved - we need to fill the caps around the pipes to prevent the ants and other insects getting into the cavity.
If anyone has any spare, please let me know.
Many thanks