Accelerated corrosion test for metal drainage pipes.

PDFTech ReportFHWA/LA-87/206La.HPR Study No. 86-1P(B)CorrosionAccelerated testsMetal culvertsLouisianaGarber, J. D.Lin, J. H.University of Southwestern Louisiana. Dept. of Civil EngineeringLouisiana Transportation Research CenterUnited States. Federal Highway AdministrationUS Transportation CollectionThis study represents an attempt to develop an accelerated test which would assist the highway engineer in evaluating the usefulness of a new type of coated steel culvert. The test method was to be short in duration (in the order of days), and the results must correlate with field results. The project chose to use electrochemical techniques to develop a laboratory method. The electrical potential of the culvert was raised above its natural potential, and it was placed in a corrosive solution containing hydrogen ions, chlorides, and sulfate ions. A total of six different types of culverts were used in the tests. The best accelerated test method developed was a 3-day high pressure oxygen test (500 psi oxygen) at ambient temperature. The coupon was placed inside a 316SS Baroid cell which elevated its potential. The percent zinc remaining on the coupon after testing was calculated using atomic absorption (AA), and was to be the basis of rating the coating. An alternative 3-day method involved the use of a potentiostat to maintain a 1-volt potential difference between two test coupons in a standard test solution. This method requires that the percent zinc on the coupons be determined from an area analysis. Both methods were able to produce results which correlated with field data