CM Method (calcium carbide measuring method)

CM stands for calcium carbide measuring. The CM method belongs to the destructive measuring methods for determining the moisture content of mineral construction materials and can be used on site. The principle of this method is based upon the chemical reaction of moisture (water) present in the construction material with calcium carbide to form acetylene (gas) and calcium hydroxide (solid) in a container. The pressure (manometer) produced by the amount of gas depends on the residual moisture content in den construction material. The procedure is described by the manufacturer of the measuring device.