This project demonstrated the capabilities of a self-repairing additive in a polyurethane topcoat (MIL-PRF-85285 Type II, Class H) applied to the exterior hangar doors in the severely corrosive environment at Corpus Christi Army Depot, Texas. Many conventional coatings when scratched or abraded, may develop corrosion that can lead to rapid deterioration of the substrate steel. The demonstrated self-repairing coating system was also applied to test panels exposed to atmospheric weathering and salt fog testing for 2,000 hours. While the self-repairing coating showed promise on the test panel exposure tests, the system was not able to protect the steel hangar doors due to the excessive mechanical impacts and stresses they are subjected to during daily operations. Department of Defense implementation of the demonstrated self-repairing coating is not currently recommended for use on infrastructure. Further evaluation would be needed to match the self-healing capabilities of the demonstrated coating with lighter-duty steel infrastructure components not subjected to the degree of impact and abrasion as the subject hangar doors. Because the self-repairing coating system did not perform any better than the conventional control coating in this project, the return on investment was zero.

No abstract

Bridges are essential to many military installations, especially in remote training areas. Like many of our nation's infrastructure bridges, U.S. Army bridges are in critical need of maintenance and repair due to the combination of wear and tear and material degradation, especially the hundreds of wood timber bridges. Repair or replacement represents a major cost to the Army that could be minimized by using cost-competitive, longer-lasting bridges. This effort determined that the innovative use of thermoplastic materials was successful in engineering and constructing a new bridge design that could safely carry the same or greater loads, be virtually maintenance-free, and be cost competitive on a first-cost basis when compared to wood timber bridges. Both the initial load testing and long-term monitoring as well as the life-cycle economic analysis for this project validated the beneficial use of the innovative thermoplastic materials and I-beam design. Moreover, this work is the first recorded effort to construct and demonstrate that a thermoplastic composite bridge of any type can bear the load of a 71-ton (64 Mg) Abrams tank. The results show that the design and materials achieved and surpassed their objectives, and they are recommended to be adopted on a widespread basis. DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents.

No abstract

This Office of the Under Secretary of Defense Corrosion Prevention and Control Program project was to demonstrate the long-term performance of an ultrahydrophobic concrete additive that blocks water intrusion and chloride penetration into concrete. The proprietary additive was to be used to repair the seawall in a highly corrosive environment at Pililaau Army Recreation Center (PARC) in Waianae, Hawaii. The deteriorating stone seawall at PARC was to be covered in a concrete veneer with a new stair access to the beach, both using the waterproofing additive. Chloride, humidity, and corrosion rate sensors were placed in the concrete veneer panels and were to be monitored for two years.Unfortunately, while the seawall veneer panels were completed, the government was unable to obtain necessary permits to allow excavation of the beach at the base of the seawall for construction of the footing. Even after it became clear that the work could not be completed under the contract for this project, the Corps of Engineers Honolulu District in Hawaii initiated their own project to complete the work by using the prepared veneer panels, but they also were unable to do so because of the permitting and environmental study requirements. DISCLAIMER:The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents.