Bond Performance between Corroded Strand and Concrete

The bond between strand and concrete plays an important role in determining the bearing capacity of prestressed concrete structures especially for pre-tensioned ones, while the corrosion of strand changes the contact conditions between them, which result in changing of structure performances. For the purpose of studying the effect of corrosion on bond performance between strand and concrete, 12 un-tensioned strand bonding specimens were made in this paper, which including 2 un-corroded and 10 corroded ones. On the basis of accelerated corrosion test and pull-out test, the distribution of corrosion cracks on the specimen surface、the distribution of concrete strain and curve of bond stress-slip of each specimen were obtained. The experimental results show that the distribution of bond stress along the embedment length was nonuniform, the peak stress value drops with the growth of corrosion crack width. On the other side, both the average bond strength of initial slip occurred at free end and maximum pull-out force declined obviously with the increasing of corrosion-induced crack width; The corrosion-induced crack has an obvious effect on the initial linear section of bond stress-slip curves.