Method of forming corrosion protection double coatings on prestressing strand and prestressing strand produced by the method

摘要

To improve tensile strength without impairing flexibility and adhesion to concrete, and to form a thick coating in a surface layer part for preventing a basis material from being exposed by damage to the coating, a method of forming double coatings on a prestressing strand includes a primary painting process after a pre-treatment process, in which a resin coating is formed only at the surface layer, a secondary painting process in which respectively individual state resin coating is formed on an outer peripheral face of each of the core wire and surrounding wires under a loosened and separated state, thereby forming a double coating for each surrounding wire, and a finishing process of tightening and retwisting the surrounding wires about the core wire to an original state. The obtained prestressing strand has the double coating portions only at the surface layer and sufficient flexibility and adhesion to concrete.