The round PVC joint is used to create pre-determined breakage points in the concrete structures. The shrinkage cracks occur at the location of the round joint. Therefore, the shrinkage joints remain watertight. Round PVC joints, also called incipient cracks, are placed during the fitting of the formwork. They can be fastened with clips.
Typically, this joint will be placed during the concreting of very long shells, in which cold joints are to be avoided.