| 摘要 |
PROBLEM TO BE SOLVED: To provide a composite sleeper and its manufacturing method for preventing side slippage while increasing the bending strength thereof and the pull-off strength of dog spikes. SOLUTION: By making the density of bunched fibers at a contact portion with ballast smaller than the density at other portions, the ballast is easily bitten and side slippage is prevented. By providing protrusions for keeping spaces between the bunched fibers neighboring each other at predetermined spaces in the longitudinal direction of the bunched fibers, the overlap of the bunched fibers with each other is relaxed, gaps in which a base material resin enters are formed, the bunched fibers are uniformly dispersed into the base material resin and the strength of the composite sleeper and the pull-off load of the dog spikes are increased. Furthermore, by changing the dimensions of the protrusions depending on positions where the bunched fibers are arranged, the density of the bunched fibers is easily changed between the contact portion with the ballast and the other portions.
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