All penetrations within concrete should be sleeved for several reasons, one being expansion and contraction of the pipe, second to allow for slight shifting of the slab or earth (hopefully it doesn't happen, but can!!!)
Either place a larger piece of pipe over the current one and pull out as the concrete starts setting, but before it cures as it is almost impossible to remove at that point, or wrap the pipes (1/2") with a sill gasket foam.
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