| 摘要 |
PROBLEM TO BE SOLVED: To obtain a granular soil material which is spread over the exposed soil on a street, in a tree-planted zone or in a park to prevent weeds from growing and to remove nitrogen oxides in the air to thereby purify the air by granulating a material having a specific gravity at least equal to that of water to a specified particle diameter, coating the granule with titanium dioxide and a water repellent, and giving a desired color to the surface. SOLUTION: The granular soil material is made from a material having a specific gravity of at least 1 to prevent it from floating in the rain water and being washed away and from being blown off by the wind. For example, a clay is kneaded with a cement, and the moisture content of the kneaded material is adjusted to about 5% to give a granular soil material base, which is granulated to a particle diameter of several mm to 10-odd mm. It is desirable to granulate in such a manner as to give granules having three different particle diameters, i.e., large, medium and small diameters. The granulated material is coated with titanium dioxide, coated to give a desired color to the surface and then coated with a water repellent (e.g. a silicone resin). This granular soil material is spread over the exposed soil, e.g. on a street to a thickness of about 7cm so as to shield the sunlight. |
