An inspector recently made us thaw the frost from the reinforcement before he would let us place the concrete. Is this necessary? We were using concrete that had been heated. Shouldn't that melt any frost on the rebars?
It is a general rule that frost should be removed from rebars. This prevents moisture buildup on the rebar that would reduce bond, and in addition it diminishes any possible nonuniformity of temperature that might affect the concrete volume and rate of cure in the vicinity of the steel.