| 摘要 |
The paving block (10) is laid on a subsoil layer (18), which allows water to seep away. It has at least one backing layer (12) made of block concrete which is permeable to water, and an additional layer (14) which is connected firmly to it. The additional layer is impermeable to water, and may be made from normal concrete, or from slabs of natural stone. It may also have a thickness of more than 8 mm, and this preferably may be between 10 mm and 20 mm. The sides of the backing blocks may have separators, which create a gap of between 4 mm and 6 mm. |
