Conductivity measurement method
With the help of conductivity measurement methods, an analysis of the construction status or the subsoil can take place in the construction industry by measuring the electrical conductivity .
It is determined u. a .:
- the moisture of the masonry , other building materials or the beams
- the concentration and distribution of salts in the masonry,
- the moisture and salinity of the subsoil
General
If liquid and solid, non-conductive materials have ions or electrons as charge carriers , they have a measurable electrical conductivity . Conductivity measurements, known as conductometry , are used primarily in electrochemistry . With the aid of conductivity measurements in liquid substances, the purity and concentration of electrolyte solutions are determined in process measurement technology .
The interpretation of measurement results is made easier by a large number of disturbance variables, such as B. contacting, specific calibration and changing salinity made difficult and complicated. The moisture content and dissolved salts cannot be clearly distinguished by measuring the conductivity. There must be close contact with the material to be examined in order to determine the electrical resistance .
Conductivity measurement method in the soil
The conductivity measurement in soils is based on the dependence of the electrical resistance of the water content. Water dissolves the ions in the ground and enables them to be transported under the influence of an electric field . Usually, the resistance is measured with the help of electrodes , which are embedded in gypsum blocks to avoid contact problems and are thus inserted into the ground. However, this calibration is uncertain due to the strong dependence on the substances dissolved in the soil water . The conductivity measurement method is therefore only used for applications with low accuracy requirements. Another, non-destructive method for measuring soil conductivity is measuring with the help of electromagnetic induction .
See also
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- K. Kupfer, Material moisture measurement: Fundamentals, measurement methods, applications, standards, Expert Verlag, 1997
- C. Hübner, 1999 "Development of high-frequency measurement methods for determining soil and snow moisture" , Scientific Reports, FZKA 6329, Research Center Karlsruhe (PDF; 3.80 MB)