| 摘要 |
The cover (1) has a grid fabric (3) associated with a water-discharging cover layer, which is chemically decomposed in alkaline environmental conditions. Surface weight of the cover layer is less than 50 g per meter square, where the cover layer is laminated on the grid fabric. The cover layer is formed as fiber composite made of alkaline degradable fibers or as fleece (2) i.e. glass fleece. Aperture width of the grid fabric is 1 mm, where the aperture width is based on expected mechanical load of the cover during displacing and based on desired composite action. |
