MMP20 SONO-DIS (option D)
Hauser
Page 33
Step 4.
Start the next individual measurement
To prevent the segregation of the concrete, it is recommended to mix the fresh concrete again after
5 measurements. With regard to the representativeness, this simply involves changing the material
mix or composition with different sized gravel pieces at the probe head (similar to a mixer probe in
a concrete mixer). Press the
"Start measurement"
key
again to take the second measurement,
which also takes approx. one second. The new measured value is used for averaging and an average
water content
value is calculated from the first and second (or more) measurements and displayed
on the LCD screen.
Step 5.
Perform addition individual measurements (back to Step 4.)
Proceed as explained under Point 4. Please note that a higher number of individual measurements
improves the representativeness and accuracy of the final result. It is strongly recommended to
take a higher number of individual measurements if the readings tend to vary greatly (e.g. due to
concrete bleeding).
After performing a certain number of individual measurements, the standard deviation
Std-Dev
should show a value less than 0.5 so that the quality of the measurement is guaranteed and the
water content result can be accepted in
l/m
3
.
The measurement series can be cleared by pressing the
key and the SONO-DIS is then ready for
a new measuring cycle.
Core moisture, core water and water absorption
SONO-WZ measures both the free water in the fresh concrete and usually 1/3 of the maximum
core water with a higher weighting of the core water of sand.
While there are types of rock that
absorb very little core water, there are aggregates, such as sandstone or lime grit, that can absorb up
to 50 liters of core water.
Therefore SONO-WZ must be set once to the concrete formulation being used, with the type of
rock or rock location.
To ensure that SONO-DIS can display the effective water or alternatively the kiln-dry water
content, it is necessary to factor in a value for the "G-Set" parameter for the type of rock used.
This value must be determined once.
If SONO-WZ is to measure the effective water:
If, for example, a rock has 15 liters core water, SONO-WZ only sees 1/3 of this amount.
The remaining 2/3 must then be specified as a negative value for the G-Set to be able to measure
the effective water content. In this example, the G-Set would be -10 liters/m
3
if the core water is
typically 15 liters/m
3
.
If SONO-WZ is to measure the kiln-dry water content:
If SONO-WZ is to measure the kiln-dry water content, enter one third of the positive value of the
core water for the G-Set! In this case, G-Set = +5 liters if the core water is typically 15 liters/m
3
.
