Q:I cannot keep my concrete within its thermal specs using cold water or ice as a cooling agent. Even worse, the melted ice or water affects the slump and air content of the concrete. Can liquid be used instead, and is it cost effective?
A:Liquid nitrogen has been used for concrete cooling at dozens of plants with great technical and economic success. When liquid nitrogen is sprayed directly on the mix in a fast-spinning truck or central mixing unit, it offers true process control. The inert liquid nitrogen can cool the concrete to lower temperatures more rapidly than ice without affecting the final properties of the product.
Liquid nitrogen concrete cooling systems, which consist of a lancing station and liquid nitrogen supply (see figure), require very little maintenance and no additional labor to operate. The nitrogen-based cooling method also can be significantly less costly depending on the local price for liquid nitrogen and water/ice.