Between October 1994 and October 1995, a unique bridge was under construction in North America. Of special note was the fact that the bridge was privately built and leased to the City of Winnipeg for approximately 20 years. Another special feature was the use of MCI®-2000 corrosion inhibiting admixture in the bridge decking, added to extend the service life of this private investment. MCI®-2020 was applied to sign-support columns aboveground. It was also slated for use in a number of Winnipeg bridges the following year, as provincial and civic engineers were recommending the use of MCI® Technology in all bridge projects at this time.
A processing facility faced the question of whether they could save the structural integrity of deteriorating, corrosion-damaged concrete cooling towers instead of replacing them at significant cost. The question was answered with an MCI® concrete repair. First, loose concrete was jet blasted off. Heavy corrosion was removed from rebar using VpCI®-423. MCI®-2023 was immediately applied to clean rebar for protection. MCI®-2038 and MCI®-2039 were used to repair concrete and restore structural integrity. Areas that did not need to be repaired were sprayed with MCI®-2020 to migrate and protect underlying steel from corrosion. The work restored the structural integrity and appearance of the concrete cooling towers at a significant cost savings compared to replacement.
The historic Alcatraz Federal Penitentiary is located on an island in San Francisco Bay. The perpetual environment of saltwater and fog has caused many corrosion problems for the National Park Service (NPS), who oversees the site. In 2008, the NPS realized something had to be done to slow down ongoing corrosion and remove loose concrete that could fall off high prison building walls and threaten visitor safety. The work was complicated by a limited budget and the designation of Alcatraz as a bird sanctuary where the bird habitat must not be disturbed by maintenance activity from February through September. NPS worked around the difficulties by contacting their Cortec® distributor for solutions. The repair ultimately involved removing spalled concrete, coating exposed steel with CorrVerter®, and applying MCI®-2020 to mitigate unseen corrosion beneath the surface. The products were easy to apply and cost-effective. Also, the fact that they could treat larger areas presented NPS with a potential cost savings on future repairs.
The Hakalau Bridge in Hawaii was suffering from steel girder corrosion caused by volcanic sulfuric dioxide as well as chloride enriched moisture from the Pacific Ocean. Some of the rusty areas on the bridge were especially hard to clean. CorrVerter® was used to prime the tight rust in these areas where good surface prep was difficult to achieve. MCI®-2005 NS was added to new concrete poured to cover the foundation and enhance the structural strength of first level bents in case of seismic activity. MCI® Mini Grenades were used in repair mortars for hand lay-up. The products’ ease of use and protective abilities made them excellent solutions to extend the expected service life of the structure.
Historical structures have significant cultural values and part of preserving our heritage is preserving these structures. Due to their importance and uniqueness, they typically require special care when it comes to rehabilitating them. Cortec® Corporation was involved in the restoration of the ring walls that exhibited signs of deterioration due to carbonation induced corrosion that was clear in the shallow concrete cover. Cortec’s surface applied corrosion inhibitor, MCI®-2020, was used to control corrosion of the imbedded reinforcement, The goal was to extend service life by 20 years using a system of surface applied corrosion inhibitor and followed up with water repellent treatment. Cortec® was able to show the effectiveness of the inhibitor and by taking corrosion rate measurements using a linear polarization device.