ERDC applies novel materials to civil works infrastructure
August 5, 2014
Aging infrastructure has become a huge problem for the U.S. Army Corps of Engineers (USACE). The mean age of our structures currently sits at more than 60 years, well beyond the original functionality and service lifespan they were designed to withstand. Keeping them in commission is becoming a liability, not only in the area of safety but also in regards to high costs and efforts; however, simply abandoning them isn't an option either. So what's the solution? U.S. Army Engineer Research and Development Center (ERDC) researchers believe they know.
"If we don't address these issues now by performing proper maintenance, including the use of durable materials, the cost of fixing these problems in the future will be even greater," said Research Civil Engineer Dr. Robert Moser. "Deterioration of our civil works infrastructure means that locks are being closed for maintenance more frequently, structures are not performing as designed and maintenance costs are increasing. In many cases this is an operations concern, affecting the movement of goods, but in some cases life-threatening safety concerns can also be raised. It's time we fix the problem rather than simply putting a band-aid on it."
Bypassing unsatisfactory traditional repair methods, researchers decided to explore the idea of applying novel materials to reconstruction and repair efforts. Novel materials are essentially new materials that are not typically used in infrastructure applications but have the potential to facilitate groundbreaking improvements in areas such as strength and increased durability. For most repair applications, main costs come from labor and equipment rather than materials so the main goal here is to alleviate the issues that cause the need for repair in the first place. According to Moser, these solutions will not only fix current ailing infrastructure, they will also be implemented into new structures to keep the problems from reoccurring down the road.
"Much of our work is focused on maintenance and repair of existing structures, since USACE is not currently building many large civil work structures," said Moser. "We have to maintain our existing inventory of infrastructure across the country. However, that's not to say that these materials cannot be applied for new construction as well and much of that is already in the works and even incorporated into current guidance documents and specifications."
Research areas included rapid repair materials, which provide the strength of traditional repair materials in hours versus weeks. The quick setting time means repairs in the field can be completed without having to make difficult decisions such as shutting down operations on a river system or closing a vital airfield runway for a long period of time. These materials also help prevent the need to delay repairs, which can mean additional deterioration and increased costs. An example can be found in fiber reinforced polymeric composites, which are used to rapidly retrofit structures to maintain or increase capacity with requiring replacement of metallic or concrete components.
High performance and ultra-high performance concretes are also being examined. ERDC has a long history of developing novel concrete formulations, resulting in an increase in both strength and toughness by up to an order of magnitude when compared to traditional concretes. With a dense microstructure that makes them significantly more durable, these materials are prime candidates to retrofit structures that have suffered from impact and abrasion or erosion damages, as well as for new construction.
Underwater repair materials, which would allow structures to be dewatered for maintenance less frequently, are another hot issue area. Because many of the current areas of deterioration concern are underwater and not easily accessible, inspection and repairs can be extremely tedious. ERDC is developing rapid repair underwater grouts and concretes, as well as investigating and demonstrating the ability to perform repairs using fiber-reinforced polymeric composites in underwater conditions.
Focus is being placed on transitioning materials that perform well in military applications for potential civil works uses. According to Moser, leveraging military engineering R&D investments means researchers can fast track many of the materials for additional uses because they understand how the materials work, their properties and best uses.
"ERDC has been doing research in this area for quite some time, from the historical Repair, Evaluation, Maintenance and Rehabilitation Program to military efforts to current civil works R&D programs," said Moser. "Since many of these issues are unique for each structure, they often require an understanding of the problem to identify which material will work best and if modifications are needed to address operational issues. Past experience means ERDC is up to the task."