Applied to concrete slabs, the process involves placing a blanket and a plastic sheet over freshly cast concrete and then sucking the excess water out.

It can sometimes produce stronger concrete slabs, allow earlier finishing of the slab surface (no waiting for bleed water), and reduce curling of the slabs by producing more uniform water cement ratio in the thickness of the slab.  It is not always an economical option.

Regards,
Richard Beneke