What is the effect of contact with concrete on such commonly used non-ferrous metals as sheet zinc, lead, copper and aluminum?
Although dry concrete will not corrode aluminum, there is always the possibility that some corrosion will take place when the concrete becomes wet. For this reason it is recommended that when aluminum is embedded in concrete the contact surfaces be protected with a bituminous coating. Copper is for all practical purposes completely immune to corrosive attack resulting from exposure to either wet or dry concrete. Lead undergoes corrosion when exposed to the moist calcium hydroxide which is formed by the interaction of cement and water. For this reason lead should not be embedded in fresh concrete or placed in contact with green concrete. When such contact cannot be avoided the lead surface may be protected with a coating of varnish, pitch, asphalt, or a wrapping of jute saturated with bitumen. Fully cured concrete will usually have no measurable effect upon lead. The surface of zinc is corroded to some extent by exposure to green concrete, but the reaction appears to stop after it has taken place on the outermost layer of the zinc. This reaction may be prevented by protecting the contact surface with the same coating materials recommended for use on lead.