The CM-Method and kiln drying are being played out against each other. Justified? No, because the CM-Method measures the free water content and kiln drying the evaporable water. That’s how both Methods can be combined and can reach the same results.
In the Handbook (Pg. 27) you can find more interesting facts about this.
The often used unit [CM-%] is actually [M-%] measured with a Carbide-Meter. The Unit [M-%] is often used with kiln drying tests/samples and indicates the amount of weight-loss referring to the dry weight. Because the chemical reaction of a testing of readiness isn’t finished, but is broken off, the results of a random cement sample tests are different when doing them with a carbide-measurement or kiln drying.
From previous tests you would expect a difference of 1 to 1.5 M-%. So the results of different measurement techniques could be differentiated more easily, people began to use the notation [CM-%].
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