Endress+Hauser Solitrend MMP20, Руководство по эксплуатации

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Solitrend MMP20 (Option D) Commissioning fresh concrete measurement
Hauser 35
9.1.4
4.
Starting 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.
‣
Press the Enter key to "Start measuring"
 The second measurement is performed; this also takes approx. 1 s. 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.
9.1.5
5.
Taking additional individual measurements
Proceed as explained in Step 4. 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 <0.5 so that the quality of the
measurement is guaranteed and the water content result in l/m 3 can be accepted.
Pressing the navigation key clears the measurement series; the device is then ready for
a new measuring cycle.
9.2 Core moisture, core water and water absorption
The SWZ probe 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 l of core water.
Therefore the SWZ probe must be set once to the concrete formulation being used, with
the type of rock or rock location.
To ensure that the device can display the effective water content 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.
SWZ probe - measurement of effective water:
If, for example, a rock has 15 l core water, the SWZ probe only sees 1/3 of this amount.
This means that 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 then =
–10 l/m³ if the core water is typically 15 l/m³.
SWZ probe - measurement of kiln-dried water:
If the SWZ probe is to measure the kiln-dry water content, one third of the positive value
of the core water must be entered for the G-Set. In this case, G-Set = +5 l if the core water
is typically 15 l/m³.
The exact positive or negative G-Set value which has to be factored in for the rock
type (location) and entered into the device can be checked or determined in two ways:
• By comparing the measurements of the SWZ probe with several correct target values for
the water content of the concrete. With concrete mixes that are blended with dry
aggregates.
• By comparing the measurements of the SWZ probe with several correct kiln-dried values
or by determining the water content after kiln-drying.
The kiln-dry water content is calculated as follows:
Kiln-dried value = effective water + core water + additives that behave like water.