Measuring Resistivity With Resipod; Making A Measurement - Proceq Resipod Family Operating Instructions Manual

3 Measuring Resistivity with Resipod

Preparing the concrete surface
The concrete surface must not be coated with any electrically insulating coating, and it should be
clean . The rebar grid beneath the surface should be marked out with the help of a rebar locator
(e .g . Profoscope) . If the concrete is completely dry it will not be possible to make a measurement
as the current is carried by ions in the pore liquid, (See 2 .2) . Therefore it may be necessary to wet
the surface .

3.1 Making a Measurement

Indication of poor connection
In the case of a poor connection, the Resipod will display one of the following alerts .
Contact selection
The steel probe tips are rugged and may be used to scratch away a thin layer of plaque on the
surface in order to make a better connection . The size of the contact however, means it is not
always possible to drive the full 200µA into the concrete to obtain the maximum measurement
resolution .
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"Open Line" indication
Bad connection of the two outer probes to the concrete
surface . No measurement possible .
Inner two probes are not making contact.
(check for holes or dry spots on the specimen)
Or Sample resistivity <1kΩcm
Material resistivity is extremely low .
Overflow
The measured resistivity is out of range . This limit is
dependent on the spacing, but it is typically a resistivity of
>1000 kΩcm .
A good connection between the
instrument and the concrete surface is
the most important factor for obtaining a
reliable measurement . Dip the contacts
in water several times before making a
measurement – use a shallow container
so you can press against its bottom
– this will fill the reservoirs . Press the
Resipod firmly down until the outer two
rubber caps rest on the surface to be
tested .
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