Post on 15-Mar-2016
description
Comparison of Surface Comparison of Surface Resistivity to Bulk Resistivity to Bulk
Diffusion Testing of Diffusion Testing of ConcreteConcrete
Christopher C. Ferraro Ph.D. Assistant In Engineering Department of Civil and
Coastal Engineering, University of Florida
Mario Paredes P.E. Mario Paredes P.E. State Corrosion EngineerState Corrosion Engineer
Florida Department Florida Department TransportationTransportation
Corrosion induced deterioration is the most common cause of bridge
degradation in Florida
Research SignificanceResearch Significance
FDOT Chloride Penetration FDOT Chloride Penetration Research ProgramResearch Program
Started In 2002, Consisted of 3 phases:Started In 2002, Consisted of 3 phases: 11stst Phase (2002-2003): Characterization of Phase (2002-2003): Characterization of
structural concrete placed in the field usingstructural concrete placed in the field using AASHTO T277/ASTM C1202 – Chloride Penetration Test AASHTO T277/ASTM C1202 – Chloride Penetration Test Surface Resistivity (Florida Method FM5-578) Surface Resistivity (Florida Method FM5-578)
22ndnd Phase(2003-2007): Find the best electrical Phase(2003-2007): Find the best electrical indicators of permeability correlated to indicators of permeability correlated to diffusiondiffusion
Bulk Diffusion (NT Build 443)Bulk Diffusion (NT Build 443) RMT (NT Build 492)RMT (NT Build 492) AASHTO T277/ASTM C1202 – Chloride Penetration Test AASHTO T277/ASTM C1202 – Chloride Penetration Test Surface Resistivity (Florida Method FM5-578)Surface Resistivity (Florida Method FM5-578)
3rd Phase (2007-2009): Surface Resistivity as a 3rd Phase (2007-2009): Surface Resistivity as a nondestructive test to evaluate field structuresnondestructive test to evaluate field structures
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The Chloride Ion The Chloride Ion Penetration TestPenetration Test
Cut and Epoxy26th Curing Day
Desiccate27th Curing Day
Cell Formation3rd Day of Test28th Curing Day
Performing Test3rd Day of Test28th Curing Day
The Chloride Ion The Chloride Ion Penetration TestPenetration Test
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Chloride Ion Penetration Test Chloride Ion Penetration Test AASHTO-T277/ASTM C1202AASHTO-T277/ASTM C1202
Stanish, K.D. et alNegatively charged ions move from the anode reservoir to the cathode reservoir.
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Chloride Ion Penetration Test Chloride Ion Penetration Test LimitationsLimitations
TemperatureTemperature Ionic ContributionIonic Contribution Hydroxyl ion formationHydroxyl ion formation Conductive MaterialsConductive Materials Effort Required for Specimen PreparationEffort Required for Specimen Preparation Cost Cost
Diffusion TestBulk Diffusion (NT Build 443)
Cylinder is sliced at 364 days of exposure for Chloride analysis
Each slice is ¼ in thick
16.5 % NaCl
Bulk Diffusion Test Bulk Diffusion Test NordTest NTBuild 443 NordTest NTBuild 443
16.5 % NaCl Solution
Sealed on All Faces Except One
Concrete Cylinder (4 in diameter, 4 in length)
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Electrical Indicators of Ion Electrical Indicators of Ion PenetrationPenetration
NT Build 443 - RMTFM5-522Impress Current
Stanish, K.D. et al
SurfaceSurface Resistivity FM 5-578
Surface Resistivity Testing
8"
Top
Bottom Probe Spacing a =1.5"
4"
Wenner Array Probe
Resistivity MeterKOhm - cm
a a a
Small AC signal
Broomfield, J. et al Applied Current
Measured Voltage
Surface Resistivity
Chloride Ion Penetration Test LimitationsChloride Ion Penetration Test Limitations
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Advantages of the Surface Advantages of the Surface Resistivity TestResistivity Test
TemperatureTemperature Ionic ContributionIonic Contribution Hydroxyl ion formationHydroxyl ion formation Effort Required for Specimen PreparationEffort Required for Specimen Preparation Cost Cost
Conductive Materials – Still a problemConductive Materials – Still a problem
Chini, A. et al 529 Data Sets
Comparison of Resistivity and Chloride Ion Penetration
Coulomb Values
Surf
ace
Res
istiv
ity
(k
-cm
)
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Precision of MethodsPrecision of Methods
Single-Operator Precision for penetration testingSingle Operator Coefficient of Variation:
• Surface Resistivity = 8.2%
• Chloride Penetration Test = 12.3%
y = 49.85x-0.7379
R2 = 0.7884 y = 42.781x-0.6125
R2 = 0.7383
1
10
100
0.1 1.0 10.0 100.0
Diffusion (10-12 m2/s)
Res
istiv
ity (K
Ohm
-cm
)
1 Year 3 Year
91 Day SR Correlation to 1 & 3 year BD
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Research ProgramResearch Program cont.cont.
The third phase of researchThe third phase of research Surface resistivity as a NDT test to Surface resistivity as a NDT test to
evaluate field structuresevaluate field structures Surface Resistivity as a Performance
Test for Transport Properties Presuel-Moreno et.al (yesterday’s sesson)
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Geometry EffectsGeometry Effects ρρreal ≠ real ≠ ρρmeasuremeasure
• Curvature of sample forces equi-potential lines into urvature of sample forces equi-potential lines into smaller smaller areas.areas.• The result is a modified resistivity reading.The result is a modified resistivity reading.
The real resitivity of concrete can be calculated byThe real resitivity of concrete can be calculated by
ρρrealreal == ρ ρmeasuremeasure/K/K
Where K is a correction factor that accounts for the Where K is a correction factor that accounts for the geometrical effects of the test (Morris, W. et al.)geometrical effects of the test (Morris, W. et al.)
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Geometry EffectsGeometry EffectsMorris, W. et al
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Geometry EffectsGeometry EffectsSurface Resistivity vs Distance
from Top of 6 x 12 Cylinder
5.0
5.5
6.0
6.5
7.0
7.5
0 1 2 3 4 5 6 7 8
Distance from Top (Inches)
Surf
ace
Res
istiv
ity (K
Ohm
s-cm
)
0 Min 15 Min 30 Min 45 Min 60 Min 75 Min 180 Min
Drying Time
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Geometry EffectsGeometry EffectsSurface Resistivity vs Time
6 x 12
5.0
5.5
6.0
6.5
7.0
7.5
0 20 40 60 80 100 120 140 160 180
Minutes
Surf
ace
Res
istiv
ity (K
Ohm
s-cm
)
0" 1" 2" 3" 4" 5" 6" 7"
Distance From Top
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4 3 2 1 -1 -2 -3 -40
30
60
180
5.0
5.5
6.0
6.5
7.0
7.5
Sur
face
Res
istiv
ity (K
Ohm
s-cm
)
Distance from Center (Inches)
Tim
e (M
inut
es)
Surface Resistiv ity vs Time and Distance
7.0-7.5
6.5-7.0
6.0-6.5
5.5-6.0
5.0-5.5
Geometry EffectsGeometry Effects
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Geometry EffectsGeometry EffectsSurface Resistivity vs Curing Condition
Class VW/C=0.39 Fly Ash=20%
0
20
40
60
80
100
120
140
160
180
0 20 40 60 80 100 120 140 160 180 200
DAYS
SUR
FAC
E R
ESIS
TIVI
TY (K
ohm
s-cm
)
Moisture Room Lime Tank Outside
RCP DATA SR 28 Days 180 Days 28 Days 180 Days Coulomb Coulomb KOhm-cm KOhm-cmMoisture Room 5792 954 7.5 40.2Lime Tank 6715 1411 7.1 25.7Outside (Air cured) 4918 1182 20.7 155.2
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References:References:“Florida Method of Test for Concrete Resistivity as an Electrical Indicator of Its Permeability”, (FM5-578) Florida Department of Transportation, 2004
“Standard Method of Test for Resistance of Concrete to Chloride Ion Penetration”, (T259-80), American Association of State Highway and Transportation Officials, Washington, D.C., U.S.A., 1980
“Standard Method of Test for Electrical Indication of Concrete’s Ability to Resist Chloride”, (T277-93), American Association of State Highway and Transportation Officials, Washington, D.C., U.S.A., 1983
“Standard Test Method for Electrical Indication of Chloride’s Ability to Resist Chloride” (ASTM C1202-94) 1994 Annual Book of ASTM Standards V 04.02, ASTM, Philadelphia, pg. 620-5
Berke, N. S., and Hicks, M.C., “Estimating the Life Cycle of Reinforced Concrete Decks and Marine Piles Using Laboratory Diffusion and Corrosion Data”, Corrosion Forms and Control for Infrastructure, ASTM STP 1137, V. Chaker, ed., American Society for Testing and Materials, Philadelphia, 1992
Broomfield, J., and Millard, S., “Measuring Concrete Resistivity to Assess Corrosion Rates”, Concrete Report from the Concrete Society/Institute of Corrosion Liaison Committee, pp. 37-39
Chini, A., Muszynski, L., Hicks, J., “Determination of Acceptance Permeability Characteristics of Performance-Related Specifications for Portland Cement Concrete”, Florida Department of Transportation, July 11, 2003
Hooton, R., Thomas, M., Stanish, K., “Prediction of Chloride Penetration in Concrete”, Federal Highway Administration, October 2001
Morris, W., Moreno, E.I. and Sagues, A. A., “Practical Evaluation of Resistivity of Concrete in Test Cylinders using a Wenner Array Probe”, Cement and Concrete Research, Vol. 26, No. 12, pp. 1779-1787, 1996
Powers, R., Sagues, A., Cerlanek, W., Kasper, C., Li, L., Liang, H., Poor, N., Baskaran, R., “Corrosion Inhibitors in Concrete Interim Report”, Federal Highway Administration, FHWA-RD-02-002, March 2002
Stanish, K., Hooton, R., Thomas, M., “Testing the Chloride Penetration Resistance of Concrete: A Literature Review”, FHWA Contract DTFH61-97-R-00022”Prediction of Chloride Penetration in Concrete”
Streicher, P.E. and Alexander, M.G., “A Chloride Conduction Test for Concrete”, Cement and Concrete Research, Vol. 25, No. 6, pp. 1284-1294, 1995