Coating Delamination by Radial Tension in Prestressed Concrete Pipe. I: Experiments

This paper is the first of a two‐part paper that deals with mortar‐coating delamination by radial tension of prestressed concrete cylinder pipe. The first part presents the results of tests (the second part presents the results of analysis performed). The radial tensile strength tests were conducted both on laboratory specimens and field pipe. The radial tensile strength of laboratory specimens was measured to evaluate the effect of shrinkage, mortar moisture and wire diameter and spacing. The radial tensile strength of mortar coating was measured on field pipe buried or exposed to the outdoors environment for a long time period. The test results show that maturing of mortar increases its radial tensile strength, while shrinkage and wire diameter have only small effects on the radial tensile strength of pipe with wire spacing in excess of two wire diameters. A significant decrease in radial tensile strength is observed for wire spacing of less than two wire diameters; a smaller decrease is observed for wire spacings in excess of four wire diameters; however, for wire spacings more than two and less than four wire diameters, the radial tensile strength is independent of wire spacing.