Evaluation of corrosion inhibitor.

PDFTech ReportFHWA/LA-80/141La. HPR Study No. 79-1C(B)Inhibitors (Chemistry)Bridge decksLaboratory testsCorrosionConcreteAdditivesLouisianaLouisiana. Dept. of Transportation and DevelopmentLaw, Sheldon M.Rasoulian, MasoodLouisiana. Dept. of Transportation and DevelopmentUnited States. Federal Highway AdministrationUS Transportation CollectionSolution to the problem of deterioration of bridge decks due to the corrosion of embedded steel has been sought by engineers for a long time. The purpose of the study was to evaluate, under laboratory conditions, the properties of concrete using a commercially available corrosion inhibitor (Darex) as an additive to the concrete.There was a limited scope to the study and evaluations were by means of a half-cell potential measurement system and visual observations. Generally the following conclusion were made: (1) Darex corrosion inhibitor does protect some against corrosion of steel embedded in concrete, but the extent has not been defined yet, (2) strength is higher for corrosion inhibitor treated concrete than for reference concrete (not treated), (3) Darex corrosion inhibitor does improve the general mix properties of air entrained concrete, (4) concrete using a corrosion inhibitor as an additive will cost approximately 22% more than conventional concrete, but will not be as expensive as other types of treatments and (5) it is not known at this time whether the protection advantages will offset the cost increases of the material.The laboratory testing performed in this study is not fully corroborative of corrosion inhibiting qualities of calcium nitrite. More research is needed in this area of corrosion protection and also in correlating the laboratory results to actual field conditions