The research presented in this paper was aimed at producing unique experimental data to gain insights into the effects of localized tensile stresses and delamination behavior in cylindrical post-tensioned concrete structures. Data of this sort is currently limited in the literature. Three curved post-tensioned concrete wall assemblies were constructed and tested to delamination failure. To investigate influences associated with specimen size and aggregate effects, all dimensions of Specimen 2 and Specimen 3 were double those of Specimen 1. While the reinforcement ratios were maintained, two different maximum aggregate sizes (3/8” for Specimen 1 and Specimen 2, 1” for Specimen 3) were used. The test results showed a specimen sizerelated influence on the onset of delamination cracking and delamination failures. The compressive stresses at the onset of delamination cracking were on the range of 0.09fc'~0.24fc', which are lower than the allowable compressive stress limit for a service load condition, 0.35fc', specified in ASME BPVC (2017). Discussions regarding initiation of delamination cracking, sectional behavior during delamination cracking, and stress concentrations around the post-tensioning ducts are presented