| 摘要 |
PROBLEM TO BE SOLVED: To enable installation even on a road where a conventional sound-proof panel can not be installed, to shorten the installation and construction period and to reduce the cost. SOLUTION: The porous concrete panel is formed to have a percentage of void of 24% to 30%, a thickness of 30 mm to 50 mm, and the dominant frequency of a sound absorption coefficient which is within a range of 750 Hz to 1,500 Hz or preferably near 1,000 Hz. COPYRIGHT: (C)2006,JPO&NCIPI
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