what can I use to seal a cracked plastic soil pipe?

I have a plastic soil pipe that has a crack and is leaking where it passes through a reinforced concrete floor between my bathroom and the utility room beneath it. To strip this out and replace it will be a major and expensive undertaking as it is towards the end of the system from two bathrooms and has all solvent welded joints. Is there a product that can be injected or sprayed into the 5cm gap around this pipe that will effectively seal the leak.

M. J. Wilson
February 2010