1. Comparison of Surface Resistivity to Bulk Diffusion Testing of Concrete Christopher C. Ferraro Ph.D. Assistant In Engineering Department of Civil and Coastal Engineering, University of Florida Mario Paredes P.E. State Corrosion Engineer Florida Department Transportation

2. Corrosion induced deterioration is the most common cause of bridge degradation in Florida Research Significance

3. FDOT Chloride Penetration Research Program Started In 2002, Consisted of 3 phases: 1 st Phase (2002-2003): Characterization of structural concrete placed in the field using 1 st Phase (2002-2003): Characterization of structural 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) 2 nd Phase(2003-2007): Find the best electrical indicators of permeability correlated to diffusion 2 nd Phase(2003-2007): Find the best electrical indicators of permeability correlated to diffusion 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 nondestructive test to evaluate field structures 3rd Phase (2007-2009): Surface Resistivity as a nondestructive test to evaluate field structures

4. 4 The Chloride Ion Penetration Test Cut and Epoxy 26 th Curing Day Desiccate 27 th Curing Day

5. Cell Formation 3 rd Day of Test 28 th Curing Day Performing Test 3 rd Day of Test 28 th Curing Day The Chloride Ion Penetration Test

6. 6 Chloride Ion Penetration Test AASHTO-T277/ASTM C1202 Stanish, K.D. et al Negatively charged ions move from the anode reservoir to the cathode reservoir.

7. 7 Chloride Ion Penetration Test Limitations Temperature Temperature Ionic Contribution Ionic Contribution Hydroxyl ion formation Hydroxyl ion formation Conductive Materials Conductive Materials Effort Required for Specimen Preparation Effort Required for Specimen Preparation Cost Cost

8. Diffusion Test Bulk Diffusion (NT Build 443) Cylinder is sliced at 364 days of exposure for Chloride analysis Each slice is ¼ in thick 16.5 % NaCl

9. Bulk Diffusion Test NordTest NTBuild 443

10. 10 Electrical Indicators of Ion Penetration NT Build 443 - RMT FM5-522 Impress Current Stanish, K.D. et al

11. Surface Surface Resistivity FM 5-578

12. Surface Resistivity Testing 8" Top Bottom Probe Spacing a =1.5" 4" Wenner Array Probe Resistivity Meter KOhm - cm a aa Small AC signal

13. Broomfield, J. et al Applied Current Measured Voltage Surface Resistivity Chloride Ion Penetration Test Limitations

14. 14 Advantages of the Surface Resistivity Test Temperature Temperature Ionic Contribution Ionic Contribution Hydroxyl ion formation Hydroxyl ion formation Effort Required for Specimen Preparation Effort Required for Specimen Preparation Cost Cost  Conductive Materials – Still a problem

15. Chini, A. et al529 Data Sets Comparison of Resistivity and Chloride Ion Penetration Coulomb Values Surface Resistivity (k  -cm)

16. 16 Precision of Methods Single-Operator Precision for penetration testing Single Operator Coefficient of Variation: Surface Resistivity = 8.2% Chloride Penetration Test = 12.3%

17. 91 Day SR Correlation to 1 & 3 year BD

18. 18 Research Program cont. The third phase of research The third phase of research Surface resistivity as a NDT test to evaluate field structures Surface resistivity as a NDT test to evaluate field structures Surface Resistivity as a Performance Test for Transport Properties Presuel-Moreno et.al (yesterday’s sesson)

19. 19 Geometry Effects ρ real ≠ ρ measure ρ real ≠ ρ measure urvature of sample forces equi-potential lines into smaller areas.Curvature of sample forces equi-potential lines into smaller areas. The result is a modified resistivity reading.The result is a modified resistivity reading. The real resitivity of concrete can be calculated by The real resitivity of concrete can be calculated by ρ real = ρ measure /K Where K is a correction factor that accounts for the geometrical effects of the test (Morris, W. et al.)

20. 20 Geometry Effects Morris, W. et al

21. 21 Geometry Effects Drying Time

22. 22 Geometry Effects Distance From Top

23. 23 Geometry Effects

24. 24 Geometry Effects

25. 25 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