| 摘要 |
<p>During the mfr. of the stones, esp. composite stones, a fluorescent material (a) is mixed with the concrete. Material (a) pref. contains a dyestuff. In mfg. a stone from a core concrete (c) with a relatively thin shell lime facing (b), material (a) is pref. mixed only with the facing concrete (b). To obtain a desired configuration of paving stones, an assembly of stones with different fluorescent colours is pref. employed. As compared with conventional marking-out methods employed for streets, street crossings, car parks, footpaths, pedestrian zones, etc., the invention provides a zoning system visible at night and also on streets covered by rain.</p> |
