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CorMap™
A simple economical method
for identifying areas of probable rebar corrosion.
Easy to use.
Detachable electrode extension pieces
facilitate measurements in hard to reach locations.
High impedance digital meter is designed
for tough field conditions.
Electrode is designed for use on
horizontal, vertical and inverted positions.
Economical.
Conforms to ASTM C-876.
An economical
method for identifying areas of corrosion ASTM C-876.
A high impedance voltmeter is connected
between the reinforcing steel and a Cu-CuSO4 reference electrode on the
concrete surface where a measurement can be made for the half-cell
potential.
This
measurement of the probability of corrosion activity. By testing
at a fixed distance apart, a grid of half-cell potentials can be
developed and areas delineated.
Corrosion, which is an electrochemical process, occurs in
concrete when oxygen and moisture are present. The actual corrosion is
an exchange of energy within different sections of the uncoated
reinforcing steel. The relative energy levels can be determined in
relation to a reference electrode with a stable electrochemical
potential.
By connecting
a high impedance voltmeter between the reinforcing steel and a
reference electrode placed on the concrete surface, a measurement can be
made for the half cell potential at the location of the reference cell.
This then is a measurement of the probability of corrosion activity in
the steel in the vicinity of the reference cell.
The reference cell is copper in a copper sulphate solution.
By taking half cell potential measurements a fixed distance apart a
grid of half cell potentials can be quickly made and thus areas
delineated with a high probability of corrosion of the reinforcing
steel.
To analyze
the results, the measurements made with Cor Map™ can be
plotted on a grid and lines of equipotential contours
drawn, highlighting areas of possible corrosion activity.
For example the following guide is listed
in ASTM
C-876
using a copper/copper sulphate half
cell:
For readings
of 350mV and greater there is a 95% chance of active steel corrosion
For readings 200 to 350mV there is a 50% chance of active steel corrosion
For readings
less than 200mV there is only 5% chance of active steel corrosion
The method
is particularly useful for:
Bridge
Decks
Parking
Garages
Concrete
Piers & Docks
Substructure
Tunnel Lining
Foundations
C-CM-4500 | High
impedance voltmeter |
C-CM-4410 | Electrode extension pieces each 18
inches (41 cm) long |
C-CM-4400 | Reference electrode including copper sulphate
reservoir |
C-CM-4210 | Container of copper sulphate
(capacity 250 ml) |
C-CM-4220 | Wetting
agent reservoir (capacity 125 ml) |
C-CM-4420 | Dispensing sponge |
C-CM-4300 | Cable
reel with 250 ft. (80 meters) cable |
C-CM-4000 | Complete system |
