1. Evaluation of Surface Resistivity Measurements as an Alternative to the Rapid Chloride Permeability Test for Quality Assurance PI: Tyson D. Rupnow, Ph.D., P.E. Co PI: Patrick Icenogle, E.I. Mark Morvant P.E. RAC Meeting July 2011

2. Background  Permeability specifications required by LADOTD for LRFD designed bridges  ASTM C 1202 most widely accepted test  Surface resistivity test  Florida DOTD study  AASHTO round robin study (on-going)  LTRC study  Wider range of w/c ratios

3. Background  ASTM C 1202  Sample preparation  2 days of ‘testing’  Equipment cost

4. Background  Wenner Probe  Much quicker  Lower equipment cost  Shorted curing time  Portable!

5. Research Objectives  Characterize surface resistivity of concrete produced at LTRC and in field conditions  Characterize the rapid chloride permeability of the same specimens  Comparative testing  Caminada Bay Bridge Project  I-10 Twin Spans Bridge Project  LA 1 Bridge Project

6. Work Plan  Measure surface resistivity and RCP on varying ages of samples  Ages of 14, 28, and 56 days  Sample size = 4 in. x 8 in. cylinders  Over 220 test results Mixture ID w/c 0.350.500.65 100TIXXX 80TI-20CXXX 50TI- 50G120S XXX 90TI-10SFXXX 95TI-5SFXXX

7. Results – Overall Relationship

8. Conclusions  SR measurements correlate well with RCP across a wide range of values and ages  Deviations are low  Able to identify great differences in w/cm  User friendly  Save $$$

9. Recommendations  Test at 28-days of age  Purchase 11 SR meters  Training program  Develop TR procedure Permeability Class 28-Day Surface Resistivity (kΩ-cm) High < 12 Moderate 12 - 21 Low 21 - 37 Very Low 37 - 254 Negligible > 254

10. Cost:Benefit

11.  Total cost of the research & Implementation  Research: $102,878  Equipment Purchase: $30,000 (11 meters)  Estimated 1 year savings  DOTD - $96,000  Contractors: $1.5 million

12. Implementation Strategy  Training  Step-by-step of TR procedure and template  Training video  Hands on with equipment  Automated template  LTRC certification  Demonstration Projects  Equipment purchased for each district  Cost/Benefit Validation  Implementation Report