Surface resistivity as an alternative for rapid chloride permeability test of hardened concrete.

Details

• Creators:
  Jenkins, Andrew
• Corporate Creators:
  Kansas. Dept. of Transportation. Bureau of Materials & Research
• Subject/TRT Terms:
  • Concrete pavements
  • Deicing chemicals
  • Durability
  • Permeability
  • Electrical resistivity
  • Benefit cost analysis
• Publication/ Report Number:
  FHWA-KS-14-15
• Resource Type:
  Tech Report
• Geographical Coverage:
  Kansas
• Corporate Publisher:
  Kansas. Dept. of Transportation. Bureau of Materials & Research
• Abstract:
  Kansas experiences harsh winters that require frequent use of de-icing salts, making it critical to the long-term ; durability of concrete structures that the permeability is kept under control. Under current KDOT specification, the ; Rapid Chloride Permeability (RCP) test, as described in ASTM Standard C1202 (2012), or the Volume of Permeable ; Voids method, described in ASTM Standard C642 (2013), more commonly known as the boil test, must be performed ; to evaluate concrete permeability. Surface resistivity testing was investigated as an alternative to these tests. ; Testing for surface resistivity was set up to evaluate the correlation of surface resistivity with RCP and boil ; tests, the effect of loss of saturation on the sample, and the repeatability of surface resistivity testing. Results indicate a ; strong relationship (R-squared value of 0.84) between 28-day surface resistivity and 56-day C1202 RCP testing. ; Results also correlate well to a mathematical relationship derived through Ohm's Law. Surface resistivity did not have ; a strong relationship (R-squared value of 0.37) with C642 boil testing. Cylinders were cast to evaluate the effect of ; saturation levels and differential sample drying. Cylinders were allowed to dry for varying lengths of time at different ; ages. Results indicated that allowing the samples to dry, regardless of the length of drying time and the age at which ; the samples were drying, increased the surface resistivity results by an average of 15%. Through the course of this ; study, including all samples tested, the standard deviation and coefficient of variation on any given set of cylinders is ; 1.4 and 4.9%, respectively. If only samples used for the correlation of 28-day surface resistivity to 56-day RCP are ; used, the coefficient of variation is 4.2%. A cost-benefit analysis was performed to evaluate the monetary savings ; resulting from this research. A triennial analysis indicates a total cost savings by KDOT and contractors of ; approximately $980,000 and a cost-benefit ratio of 9.2. ; As a result of this research, recommended specification limits have been developed for surface resistivity ; testing. As of January 2014, surface resistivity testing has been added to KDOT Standard Specifications as an alternate ; test method for concrete permeability.
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• Format:
  PDF
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/28687/dot_28687_DS1.pdf
• File Type:
  [PDF - 775.74 KB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:f1e17bb3232ffb68c58ebf05e997fb8607f494ece60c86ced439a7d280e2070a