PVC liquid repair?

[slowlearner]

I would like to 'sleeve' a basement toilet waste line which is unfortunately in cement. Although this is new construction I found out the plumber put a rubber sleeve to extend the 3" pipe rather than PVC. I am afraid the rubber will eventually degrade because it would already cause a low section in the pipe for about 3-4 inches at the sleeve. I am wondering if there is something I could do to 'sleeve' the rubber with an epoxy of some sort or if it is not worth bothering with. Thanks for the help