| 摘要 |
<p>Formed on a substrate roadbed layer (4) is a cushioning layer (5) having a thickness of 50 mm to 200 mm and composed of elastic chips, which are formed by an elastic material to have a size of 7 mm to 0.05 mm, preferably 2 mm to 0.5 mm and a specific gravity of 1.8 to 3.5, alone or a mixture of the elastic chips and sand. The cushioning layer (5) contains elastic chips in 3 wt.% or more. The elastic chips are formed by blending a material selected from synthetic rubber, natural rubber and synthetic resin with a specific gravity adjusting material, which is composed of inorganic grains having a specific gravity of 3 or more.</p> |
