Is there any specifications specifying the maximum content of various metals in the sand used for cement concrete ?
I've seen the concrete finished with metal shavings after the pour. I don't know if there is a regulation against it being used as partof the mix, but it seems that it could be dangerous. Inside the pour stays damp somewhat and any easily broken down carbons could cause a failure in the structure; I guess. The steel in the finish and the iron rods are not in the batch and are seperate entities for support and esthetics.
