Electrical Potentials
description
Transcript of Electrical Potentials
Building & Construction Research and ConsultancyBCRC
Electrical Potentials
Building & Construction Research and ConsultancyBCRC
Electrical Potential Mapping
High corrosion risk at construction joint due
to easy accessHigh potential gradient between leeward and
windward side of beams
High corrosion riskat piles wheresplashingsevere
Building & Construction Research and ConsultancyBCRC
Potential WheelCONTOUR PLOT:- SCANS:001-017
CONTOUR BOUNDARIES(MV)0500 0400 0350 0300 0250 000
ROW RES:012MM COLUMN RES:015MM
SCAN 001 V/G=100MV H/G=0200MM
Building & Construction Research and ConsultancyBCRC
Half-cell Potential Map of Roof Area A only 2 of 363 potentials: < -350 mV; 41 potentials : -200 to –350 mV (CSE)
0.0 0.5 1.0 1.5 2 .0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6 .0 6.5 7.0 7.5 8.0
Length South tow ards N orth (m )
0.0
0.5
1.0
1.5
2.0
2.5
Wid
th E
ast t
owar
ds W
est (
m)
Building & Construction Research and ConsultancyBCRC
Potential Curvature Map of the Roof Area A
(Hot spots are highlighted along cracks/joints)
0.0 0.5 1.0 1.5 2 .0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6 .0 6.5 7.0 7.5 8.0
Length S outh tow ards N orth (m )
0.0
0.5
1.0
1.5
2.0
2.5
Wid
th E
ast t
owar
ds W
est (
m)
Building & Construction Research and ConsultancyBCRC
0.0 0.5 1.0 1.5 2 .0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6 .0 6.5 7.0 7.5 8.0
Length South tow ards N orth (m )
0.0
0.5
1.0
1.5
2.0
2.5
Wid
th E
ast t
owar
ds W
est (
m)
0.0 0.5 1.0 1.5 2 .0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6 .0 6.5 7.0 7.5 8.0
Length South tow ards N orth (m )
0.0
0.5
1.0
1.5
2.0
2.5
Wid
th E
ast t
owar
ds W
est (
m)
Potential Curvature Map
Potential Contour Map
Building & Construction Research and ConsultancyBCRC
Electrical Potentials British BS 1881, Testing Concrete Pt 201 USA ASTM C876-91 German DGZP B3 Swiss SIA 2006 (most comprehensive)
Building & Construction Research and ConsultancyBCRC
Equipment
ElectrodeDisplay unit
Building & Construction Research and ConsultancyBCRC
Canin with 4 wheel probe array
Building & Construction Research and ConsultancyBCRC
Corrosion Values
Guideline Values (ACI 222) to determine possibility of corrosion for a Copper-Copper Sulfate Reference Electrode
mV vs. CSE
0 to -200
-200 to -350
Less than -350
Probability of Corrosion
<10%
Uncertain
>90%
Building & Construction Research and ConsultancyBCRC
m
0.00
0.15
0.30
0.45
0.60
0.75
0.90
1.05
1.20
1.35
1.50
1.65
1.80
1.95
2.10
2.25
0.000.150.300.450.600.750.901.051.201.351.501.651.801.952.102.252.402.552.702.853.003.153.303.453.603.753.904.054.204.354.504.654.804.95
Cumulative frequencyRelative frequency
Parking place inmulti-story car park
Building & Construction Research and ConsultancyBCRC
Potential Measurement
Requires skilled operative For measurement
Ensure stable measurement Determine if results will be
meaningful
For interpretation assess other factors affecting
the result
Use to: identify if corrosion initiated locate areas for laboratory
samples determine extent of corrosion
activity Affects method of repair For assessment of quantities