Bond performance of pretensioned concrete systems

Prestressed concrete technology has revolutionized the infrastructure growth in many countries, especially that of the bridge sector. The bond between prestressed strand and concrete is very important for achieving good structural performance. However, some of the codal provisions have not given enough consideration to the bond strength of pretensioned concrete system in design. This paper presents the results from a preliminary experimental program on the bond strength of 7-wire strands embedded in M35 and M55 concretes. A pull-out test method was developed, and the same was used to determine the bond strength. The bond behavior and the mechanisms at the strand–concrete interface are also discussed. Bond strength of 7-wire strand in M55 concrete is found to be about two times more than that in M35 concrete.