Abstract: Outer cables disposed in a box girder in the longitudinal direction of a box girder bridge to prestress the box girder each have a transparent sheath made of a transparent polyethylene resin, vinyl chloride resin, polypropylene resin or the like, thereby allowing the grouting condition in the sheath to be inspected reliably and easily. If a colored grout is filled, the filling condition can be inspected even more reliably and easily. In addition, it is possible to readily find a portion left unfilled after the grout has hardened and to refill it for repairing by using openings for injection and ejection made at each side of the void left.

Abstract: A thermosetting resin composition for prestressed concrete tendon, wherein the composition does not harden until the completion of the straining of the tendon, which is the inherent object in the post-tension technique, even if the heat storage temperature in the concrete structures elevates from 30° C. to 80° C. or higher due to heat of hydration reaction in setting a concrete, particularly 95° C. that is the maximum temperature in solidifying a concrete, and the composition including the site of 30° C. or lower where there is substantially no partial heat storage due to heat of hydration reaction in setting the concrete hardens within the prescribed period of time under spontaneous environmental temperature after the subsequent natural cooling, thereby achieving anti-rust and anti-corrosion of the tendon and also adhesion and integral bonding of the tendon and the concrete, a use method thereof and a prestressed concrete tendon.