| 摘要 |
Sand for use in a concrete mix is treated by intimately mixing it with calcium hypochlorite to eliminate the deleterious effects of pyrite and marcasite in the sand. Preferably a slurry of sand containing calcium hypochlorite is rendered alkaline by addition of caustic soda or lime, and the mixture aerated by agitation in the presence of air. According to the Provisional Specification, the calcium hypochlorite may be replaced by one or more of potassium permanganate, potassium dichromate, sodium hypochlorite solution, or hydrogen peroxide solution.ALSO:Sand is treated during incorporation into a concrete mix by intimately mixing it with calcium hypochlorite, to eliminate the deleterious effect of pyrite and marcasite in the sand. Preferably calcium hypochlorite is added to a concrete mix containing Portland cement, water, and sand, with or without other aggregate and/or alkali, and aerating the mix by agitation in the presence of air. According to the Provisional Specification, the calcium hypochlorite may be replaced by one or more of potassium permanganate, potassium dichromate, sodium hypochlorite solution, or hydrogen peroxide solution. |
