Permeability of Concrete ― Comparison of Conductivity and Diffusion Methods

This report details research conducted on methods used to rapidly determne the resistance of concrete to the penetration of chloride ions. These methods, based on the electrical conductivity of concrete were Rapid Chloride Permeability (RCP) [American Association of State Highway and Transportation Officials (AASHTO) T277, ASTM C1202], Rapid Migration Test (RMT) (NordTest NTBuild 492), Surface Resistivity (SR) (FM 5-578), and Impressed Current (FM 5-522). The results of these conductivity tests were compared to the Bulk Diffusion (NordTest NTBuild 443) and AASHTO T259 test methods, which allow a more natural penetration of the concrete by the chlorides. Nineteen different mixtures were prepared using materials typically used in construction in the State of Florida. Twelve mixtures were laboratory prepared and the remaining seven mixtures were obtained at various field sites around the State. The concrete mixtures were designed to have a range of permeabilities. Some of the designs included such pozzolans as fly ah and silica fume. One mixture was prepared with calcium nitrate corrosion inhibitor. Diffusion coefficients were determined from both the Bulk Diffusion (BD) and AASHTO T259 tests using a 364-day chloride exposure period. Two procedures were used to evaluate the data collected from the AASHTO T259 test; total integral chloride content and by fitting the data to Fick's Second law of diffusion equation to obtain an apparent diffusion coefficient. The electrical results from the short-term tests RCP, SR and RMT at 14, 28, 56, 91, 182 and 364 days of age were then compared to the two long-term diffusion reference tests. It was found that correlations between the RMT and the long-term tests were equal or slightly better than those obtained by the RCP and SR tests. RMT test was found to be less effected by the presence of supplementary cementitious materials and was applicable to wider range mineral admixtures in concrete than the RCP and SR tests. The surface resistivity test was conducted using two methods of curing, one at 100% humidity (moist cured) and the other in a saturated lime solution. The comparison of results of the SR tests between the two curing procedures showed no significant differences. Therefore, it was concluded that either of the methods will provide similar results. A new calibrated scale to categorize the equivalent RCP measured charge in coulombs to the chloride ion permeability of the concrete was developed. The proposed scale was based on the correlation of the 91-day RCP results related to the chloride permeability measured by a 364-day Bulk Diffusion test.

• Record URL:
  https://fdotwww.blob.core.windows.net/sitefinity/docs/default-source/research/reports/fdot-bd536-rpt.pdf
• 
• Corporate Authors:

  University of Florida, Gainesville

  Department of Civil and Coastal Engineering
  Gainesville, FL  United States  32611-6580

  Florida Department of Transportation

  Structures Research Center, 605 Suwannee Street
  Tallahassee, FL  United States  32399
• Authors:
  • Vivas, Enrique
  • Boyd, Andrew J
  • Hamilton III, H R
  • Bergin, Michael
• Publication Date: 2007-6

Language

• English

Media Info

• Media Type: Print
• Edition: Final Report
• Features: Appendices; Figures; Photos; References; Tables;
• Pagination: 238p

Subject/Index Terms

• TRT Terms: Admixtures; Chlorides; Concrete; Corrosion; Data collection; Electrical resistivity; Ions; Mixtures; Permeability; Test procedures
• Uncontrolled Terms: Diffusion coefficients
• Geographic Terms: Florida
• Subject Areas: Highways; Materials; I32: Concrete;

Filing Info

• Accession Number: 01055153
• Record Type: Publication
• Report/Paper Numbers: 4910 45 04 992-12 (00026899)
• Contract Numbers: BD 536
• Files: TRIS, ATRI, STATEDOT
• Created Date: Aug 23 2007 10:40AM