No spark fine stone concrete construction points

What are no spark fine stone concrete construction points not angry fine stone concrete construction points 1. Stone chips used in the preparation of spark not hair, fine stone or sand and gravel, should be based on calcium carbonate as the main component of marble or dolomite, limestone. 2. No spark fine stone concrete must pass a test before use, to the stone and concrete after hardening in a dark room on the emery wheel friction test, once proved sparkless before use. 3. Before the processing of raw materials, should prevent other stone types of impurities and inclusions. In the process of processing, should be a magnet inspection. Check it again before mixing, to prevent impurities mixed with.