This paper is a report on the results of studies about post-tensioned unbonded prestressed concrete beams. Test results of 14 T-beams are given, involving (1) three bonded prestressed concrete beams (2) six post-tensioned unbonded concrete beams (3) five post-tensioned bondless prestressed concrete beams using tendon covered asphalt. For various effective prestress force, the characteristics of these three types of prestressed concrete beams are compared in terms of load-stain relationships, load-deflection relationships, flexural rigidity and ultimate strength of beams failing in flexure.
