RUST PROOF COATED PRESTRESSED CONCRETE STRAND AND ITS PRODUCTION AND DEVICE FOR PRODUCTION

摘要

PROBLEM TO BE SOLVED: To obtain a prestressed concrete(PC) strand in which voids between a core line and each of side lines are completely buried with a rust proof material and at the same time capable of coating the outer layer of the side lines, and to provide a method for its production and a device for the production. SOLUTION: This PC strand is obtained by inserting a PC strand 3 obtained by twisting around plural side lines on the outer circumference of a core line into a helical die 17 along the twist of the strand installed at an introducing opening part 14 of a cross head part 6 of an extruder, passing the strand through a compressed supplemental head part 7 continuously to generate a backflow pressure in a compressed thermoplastic synthetic resin, filling the resin at the same time of forming a gap among the core line and the side lines by effecting a reverse directional power against the twist of the strand, and forming and adhering a rust proof coating layer at the whole circumference of the core line and side lines of the PC strand.