2011 Volume 49 Issue 6 Pages 6_18-6_24
When voids are left ungrouted, steel tendons in prestressing cables tend to be corroded by the water, salt or other matters penetrating into the cables, ultimately being fractured. Fracture of steels results in a reduced load bearing performance of the members as well as may cause a danger of accident to a third party as concrete debris falls at the impact of fracture. Accurate evaluation of the filling of PC grout is therefore extremely important for the maintenance of prestressed concrete structures. Nondestructive inspection techniques are preferable for the PC grout evaluation due to no damage to the structures being inspected. Various methods have been developed in many fields and applied to investigations on existing bridges in recent years. This is a technical report on nondestructive inspection techniques for concrete based on elastic-wave methods, with a specific focus placed on impact elastic-wave method for transverse prestressing cables of concrete slabs and impact-echo method which is applicable to internal cables in the post-tensioning system.
