When high strength bolted frictional joints are used for repairing and reinforcing a steel bridge, the paint on the existing member is generally removed by using a disk grinder. Then, it is difficult to secure the required slip coefficient, because the frictional surface is finished smoothly. In this study, exposure tests, slip tests and observation of cross sections were carried out to investigate the performance of high strength bolted joints frictional in which the frictional surface rusted using the improved rust accelerator. As a result, the slip coefficient of the high strength bolted frictional joints which are rusted with the rust accelerator satisfied 0.40 and showed the possibility of the application of the rust accelerator to the civil engineering structures.
