| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to use in a screwing technique and to remarkably reduce decreasing in strength of the outer peripheral face of a pipe body during screwing caused by abrasion and cutting. SOLUTION: While a cylindrical form mounted with a fitment for a receiving opening on its one end and a fitment for an inserting opening on the other end is continuously rotated under a condition where an iron reinforcement basket 10 is arranged near the inner peripheral face of the fitment for the inserting opening in the cylindrical form, a concrete outer layer 13 is formed near the iron reinforcement basket 10. A fiber-reinforced layer 16 containing the iron reinforcement basket 10 is formed on the inner face of the concrete outer layer 13, and a concrete inner layer 18 with a specified thickness is formed on the inner face of the fiber-reinforced layer 16. A fiber-reinforced layer 19 is formed on the inner face of the concrete inner layer 18, and a cement layer 20 is formed on the inner face of the fiber-reinforced layer 19 to form the fiber-reinforced layer on the inside of the concrete outer layer. In addition, as the fiber-reinforced layer is formed after the iron reinforcement basket is arranged in the cylindrical form, it is possible to perform continuous molding without stopping the cylindrical form during molding. COPYRIGHT: (C)2006,JPO&NCIPI
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