The electrical conductivity of concrete is an electrolytic process that takes place by the movement of ions in the cement matrix.
This ionic movement will occur when contaminants such as chloride ions or carbon dioxide are introduced into the cement mortar matrix. A highly permeable concrete will have a high conductivity and low electrical resistance. Because resistivity is proportional to current flow, the measurement of the electrical resistance of concrete provides a measure of the possible rate of corrosion. Since carbonation seriously affects surface resistance, measurement on the concrete surface should be avoided.
C412-01 resistivity meter has two probes spaced 5cm (1.97 inches) apart which are placed in two holes drilled to a depth of 8mm (3/8 inch) and filled with conductive gel. The concrete resistivity is displayed on an LCD when the control switch is activated.
The following table correlates a range of values vs. the possible rate of corrosion of the reinforcement bars.
|
Resistivity
Level
(kΩcm)
|
Possible Corrosion Rate of Reinforcement Rebars
|
|
<5
|
Very High
|
|
5 to 10
|
High
|
|
10 to 20
|
Moderate to Low
|
|
>20
|
Insignicant
|
- Measuring range: 0.5 to 20 kΩ cm, with 0.1 kΩ resolution.
- 2-probe array spacing: 5 cm
- Display: LCD 4 . digit
- Battery operated with 100 hours operating time
The instrument is supplied complete with drill bit, gel, template,
accessories, carrying case.
Dimensions: 400x270x130 mm
Total weight: 4 kg