The Bridge Design Section of the Louisiana Department of Transportation and Development (DOTD) is transitioning statewide to load and resistance factor design (LRFD) for reinforced concrete structures. This change in design procedures requires testing more samples for permeability to ensure adequate protection against corrosion.
The personnel hours for subjecting these samples to the traditional rapid chloride permeability test were estimated in the tens of thousands per year. In an effort to reduce sampling cost, while maintaining the needed standards, the Louisiana Transportation Research Center (LTRC) investigated the use of a surface resistivity device for the quality assurance and acceptance of structural concrete.
Based on the results from the study, Louisiana DOTD developed the Test Method for Surface Resistivity Indication of Concrete’s Ability to Resist Chloride Ion Penetration. A specification was prepared to incorporate the surface resistivity test into Louisiana DOTD’s standards and specifications. The estimated combined savings for Louisiana DOTD in the first year of implementation total about $1.6 million.
The research project cost $103,000—a cost–benefit ratio of more than 15. The preliminary analysis shows that the department can save a significant amount of money by switching to the newer, faster surface resistivity test method.