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5.5 Helpful references and findings from user practice
Mixing in the laboratory:
For mixing with dry aggregates, depending on the rock, a certain waiting time must be taken into account before
the measurement takes place, as the saturation time depends on the type of rock. If the measurement is started
too early on dry rock, the measured water content will be too high because the core water has not yet been
absorbed by the rock!
Subsequent adding of water in the laboratory:
Subsequent mixing of water into a fresh concrete in the bucket (e.g. +50 grams of water to turn a concrete with
175 liters/m
3
into a concrete with 185 liters/m
3
) leads to considerable deviations. During the mixing in drops
of water can escape from an open bucket, in addition the water evaporates very quickly on the bucket wall.
Depending on the mixing time, errors of up to 5 liters/m
3
may occur.
Air pores and glass fibers:
Air pores and glass fibers reduce the concrete density and thus the displayed moisture. This can be compensated
with the parameter G-Set.
Concretes with steel fibers:
Measurement deviations can occur due to the steel content. This can be compensated with the parameter G-Set.
If the standard deviation StdDev value is still larger than 0.5 after significant more than 5 measurement cycles,
the concrete mixture is probably too inhomogenous. In this case it is recommended to mix the concrete with a
professional stirrer inside the bucket and place the probe again inside the bucket to perform more measurements.