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Density ranges:
Concrete:
Floor screed:
Anhydrite floor screed:
CM method
Another common method of determining the moisture of the bottom layer
of screed is the CM method. The accuracy of the CM method depends on
various parameters and is not suited for a comparison with the humimeter
GF2 resp. for material calibration. In the following chart of producers of CM
devices you can find comparative values of measurements in drying
chamber in weight% to CM% for some concrete types. Please find
comparative values for other concrete types in the user manual of your CM
device.
CM calibration curve
The CM floor screed calibration curve is a conversion from water content
into CM %. The measurement values of this calibration curve are guidance
values and do not replace the CM method. However, via the non-destructive
measuring process of the GF2 the measurement is simplified. Subsequently
a CM measurement according to the norm is recommended
weight %
cement
screed
weight %
anhydrite
floor
concrete
weight %
B15,B25,B35
If your CM device shows a cement screed moisture value of 1.8 CM%, this
value corresponds to 3.2 weight% corresponding to the norm method in the
drying chamber.
Version 1.0_en
between 2200kg/m³ and 2600kg/m³
between 1800kg/m³ and 2200kg/m³
2600kg/m³
1.8
2.2
0.7
1.0
CM %
0.1
0.3
0.1
0.3
CM %
1.3
0.3
CM %
2.7
3.2
3.6
1.4
1.8
2.1
0.6
1.0
1.4
0.6
1.0
1.4
1.9
2.5
3.2
0.8
1.3
1.7
4.1
4.5
5.0
2.5
2.9
3.2
1.8
2.2
2.5
1.8
2.2
2.5
3.8
4.4
5.0
2.2
2.7
3.2
page 5
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