Resistivity meter to assess corrosion currents in concrete.
- Confirm readings made with either Cor Map System
Features & Benefits
- Assesses damaging corrosion currents in concrete.
- Economic and easy to use.
- Direct digital readout of resistivity. Measuring from two small holes avoids the problems and errors of surface measurements.
- Used in conjunction with CorMap™ System to produce resistivity plots.
Assesses Concrete Resistivity.
OhmCorr™ has two probes spaced 1.97″ (5cm) apart which are placed in holes drilled to a depth of 3/8th” (8mm) and filled with conductive gel. The direct digital read-out of resistivity is displayed on the LCD when the control switch is activated. OhmCorr™ and CorMap™, when used together, provide an economical and sound diagnostic system of corrosion in reinforced concrete.
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.
The James resistivity meter, OhmCorr™, 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.
(K OHMS CM)
|POSSIBLE CORROSION RATE OF
|5 to 10||High|
|10 to 20||Moderate to Low|
The James OhmCorr™, when used in conjunction with the James CorMap™ System provides an economic and sound means of diagnoses of corrosion in reinforced concrete.
|Weight complete in carrying case||8 lbs (4 kilos)|
|Display:||4-1/2â€ Digit in LCD|
|Resolution:||± 0.1K ohms cm (± 1 Digit)|
|Range:||0.5 – 20K ohms cm|