Endress+Hauser Solitrend MMP20, Руководство по эксплуатации

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Solitrend MMP20 (Option D) Commissioning
Hauser 17
Special (gap-graded U)
The probe measures slightly too much water and therefore has to adjust the water content
downwards slightly
• Very little or no gravel of size 2/8mm or 4/8mm
• Standard admixtures, standard additives as well as PCEs
7.6 General G-Set parameter
The probe measures both the free effective water in fresh concrete and a share of the core
water or absorbed water. 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. The core or absorbed water is not used to bind the cement and is therefore not
processed for the w/c-ratio.
7.6.1 The SWZ probe measures three types of water
In principle, the probe measures the water parts as the kiln-drying method
The free water
The free water in the concrete mix which enters into the calculation of the w/c-ratio. This
water is the actual value that is sought when using the probe.
A share of the core water
Water that is absorbed by the aggregates. The probe can only measure a percentage
(approx. 1/3) of this core water. The core water can be 10 to 35 l/m³ depending on the
type of rock. This (correction) value is represented in the G-Set parameter (approx. 2/3 of
the core water), depending on the formulation and rock. The G-Set value is typically
approx. –10 l/m³ assuming a core water content of 15 l/m³. These –10 l/m³ are then
automatically subtracted from the measurement in the handheld device so that the
reading in the handheld device matches the effective water content. See also the chapter
on "Core moisture, core water and absorbed water".
Additives
Additives that behave like water are also measured by the SWZ probe. This must be taken
into consideration.
For the G-Set parameter, it is therefore necessary to adjust the probe (one time only) to
the type of rock that is used, which depends on the concrete formulation. To be able to
display the effective (or kiln-dried) water content in the handheld device, it is necessary to
factor in a value for the "G-Set" parameter for the formulation used with the type of rock.
This value must be determined once.
If the water content that the probe displays for a special concrete is too high, G-Set must
be adjusted by the corresponding number of liters. The exact G-Set value to be factored in
for the concrete formulation with the rock type (location) and entered into the handheld
device can be verified or determined in two ways:
• By comparing the probe measurements with several correct values for the water content
of the concrete, for example by mixing concrete with dry aggregates.
• By comparing the probe measurements with several correct (!) kiln-dried values after
kiln-drying. It is important to take the possible sources of error into consideration during
the kiln-drying process.
The kiln-dry water content is calculated as follows:
Kiln-dried value = effective water + core water + additives that behave like water. See
also the chapter on "Core moisture, core water and water absorption".