Impact-Echo Scanning Evaluation of Grout/Void Conditions Inside Bridge Post-Tensioning Ducts for Tendon Corrosion Mitigation

Post-tensioned (PT) systems have been widely used for bridge transportation systems since the late 1950s. If a good quality control plan is not implemented, however, there is a strong possibility that during construction the ducts may not be fully grouted. This results in voids in some areas and the associated lack of cover for PT tendons that increase their risk of corrosion. Thus, over the long-term, water can enter the tendon ducts in the void areas, resulting in corrosion of the tendon.