摘要:
PROBLEM TO BE SOLVED: To provide a PC (prestressed concrete) steel stranded wire having higher strength than conventional strength and affording sufficient fixing efficiency and to provide a concrete structure using the steel stranded wire. SOLUTION: The high-strength PC steel stranded wire having the higher strength than the conventional strength and affording the fixing efficiency sufficient for practical use can be obtained as follows. The steel stranded wire is 7 stranded constitution prepared by stranding one central wire with 6 side wires. The steel stranded wire is regulated so that the outside diameter is 15.0-15.6 mm, the total cross-sectional area is 135-148 mm 2 , the tensile load of the whole stranded wire is ≥310 kN and the tensile load of the side wires is ≥80% of the tensile load of the central wire. COPYRIGHT: (C)2008,JPO&INPIT
摘要:
PROBLEM TO BE SOLVED: To form a thick coating layer over the surface layer (external surface) of a PC-steel stranded wire without damaging the flexibility thereof as well as a bonding strength when bonded to concrete, so as to improve tensile fatigue characteristic and avoid exposure of under-materials due to damaged coating layer. SOLUTION: The subject method of this invention comprises the following steps A to C. Step A is a pre-treatment for carrying out an under-material adjustment by unbinding the returning side-wire of the PC-steel stranded wire 1 from its core-wire. Step B is a primary coating treatment for loosely stranding a side-wire with respect to the core-wire, and then applying synthetic resin powder as a coating material to the whole surface layer except a spirally ditched portion formed due to stranding, thus forming a resin coating layer only on the surface layer. Step C is a secondary coating treatment for unbinding the side-wire of the PC-steel stranded wire 1 from the core-wire thereof, applying, by way of core-wire adjustment means, the synthetic resin powder coating material to the periphery of the unbound core-wire as well as side-wire, thereby separately forming resin coating layers producing double coating in certain portions of the side-wire. A final step is to strand the side-wire with respect to the core-wire to return the side-wire to its original position, thereby ensuring that the doubly coated portion appears on the surface layer of the PC-steel stranded wire. COPYRIGHT: (C)2005,JPO&NCIPI
摘要:
PROBLEM TO BE SOLVED: To provide a method for rustproofing processing of a PC steel material by which coated materials are not damaged by readily following elongation and bending of the PC steel material and are not easily impaired during handling at a site of civil engineering and construction and the relaxation in rustproofing coating treatment is not increased. SOLUTION: The PC steel material 1 composed of a PC steel rod or PC steel stranded wire is preheated, passed through a synthetic resin molding machine 5 for first coating, the surface of the PC steel material 1 is subjected to primary coating with a soft thermoplastic resin containing an adhesion promoter. Then the coated PC steel material is passed through a synthetic resin molding machine 7 for second coating and the surface of the first coating is subjected to second coating by fusing a rigid thermoplastic resin to the surface of the first coating. COPYRIGHT: (C)2004,JPO
摘要:
PROBLEM TO BE SOLVED: To provide a stranded wire that can sufficiently exert an effect of forming a resin film for a long period, has a high durability and is excellent in reliability.SOLUTION: A stranded wire 1 is provided with a resin film 4 formed on at least outer peripheral surface side. The resin film 4 is mainly composed of a polyvinyl butyral resin which has a butyralation degree of 40-85 mol% and whose content of hydroxy group in a molecule is regulated within a range of 11-27 wt.%.