38
Handling the Lancehead-Shaped Probe
SONO WZ
Translation of the Original Instructions for Use
Highly flowable concrete has a tendency
to separate, and measurements are not
easy to take. There is a risk of larger frac-
tions accumulating at the bottom of the
bucket. Furthermore, there is the risk of
fine particles accumulating around the
probe surface after the lancehead-shaped
probe has been inserted, which could
lead to an excessively high water content
being measured. We, therefore, recom-
mend the following procedure for con-
cretes with flow rates F5 to F6:
Darr sampling and the Darr test of con-
cretes with flow dimensions F5 and F6
can also be faulty. If the concrete for the
Darr test is removed from the surface or
bottom of the bucket, a difference of up
to 40 litres of water content can occur in
concretes prone to bleeding.
1. Fill a 12 l bucket up to ¾ full with con-
crete.
2. Completely insert the probe head into
the concrete with the WZ shovel (made
of plastic) in a vertical position at the
edge of the bucket. The shovel en-
sures that the larger pieces of gravel do
not “drift” laterally onto the probe head
during the measurement, which can
lead to deviations. (Fig. 15)
3. Press the tip of the probe with the
black ceramic surface slowly and diago-
nally to the opposite edge on the bot-
tom of the bucket so that the handle
rests on the edge of the bucket (Fig.
16). This ensures that there is a repre-
sentative concrete mixture on the
probe’s surface. Carry out this proce-
dure several times, whereby the inser-
tion of the probe should be moved 70°
to 90°. Delete individual readings if they
are far outside the indicated average
value.
Fig. 15
Fig. 16
Measuring Procedure for Flow Diameters F5 and F6
