The Niawiakum River Bridge 101/42 and the Palix River Bridge 101/40 are located on Sign Route 101, within the tidal zone of Willapa Bay. These bridges are subject to continuous salting from the Pacific Ocean water and mist. The bridges will be used as a test site to determine the effectiveness of the concrete admixture Darex Corrosion Inhibitor (DCI) in preventing the corrosion of reinforcing steel in concrete. DCI is a patented product containing calcium nitrite; manufactured and supplied by W.R. Grace & Co., Inc.
DCI, used in sufficient quantities as a concrete admixture, purportedly strengthens the passivating film around the reinforcing steel, thereby preventing corrosion.
The effectiveness of DCI in preventing corrosion will be determined by comparison with control sections located in members of each bridge. The control members were constructed without the DCI admixture. All reinforcement in the control and experimental members is uncoated, and has the same minimum cover requirements as in the DCI-treated members.
The purpose of this experimental project is to assess the long-term effectiveness of DCI as a corrosion inhibitor