By their very nature, retarding admixtures are supposed to slow the rate of cement hydration, hence slowing the rate of Slump loss, But, in a continuously mixed concrete, they not only do not slow down the rate of slump loss but, rather, they accelerate it.However, it was found that the use of flyash as a partial replacement for cement may reduce the rate Of slump loss, depending upon the replacement percentage and the loss on ignition of the fly ash used.