Are there any problems associated with casting SFRC against a water proof membrane?
No failures of the plastic liner due to fiber punctures have ever been identified. the abrasion from sharp aggregates during placement of the concrete poses just as big of a threat to the liner as do the steel fibers. After placement the fibers tend to move around and re-orient themselves during vibration which relieves any pressure of an individual fiber on the liner created during placement. Many projects using SFrc are constructed with cast-in-place and sprayed shotcrete directly in contact with water proof membranes.