DESCRIPTION: In a global scenario, pavement infrastructures constitute the key element for air transportation systems. As aircraft operating surfaces, pavements are intensively used and their failure due to serious damage—either structural or functional—determining service interruptions imposes considerable impact on operations. Limitations on pavement accessibility can even prevent successful execution of missions. Therefore, it is of extreme importance to identify or develop a material or series of materials to serve as a pavement capping layer, which quickly reach a state of setting or rapidly cure after application to a condition of strength sufficient to restore the ability to support aircraft traffic. In the context related to damage and subsequent repair, two categories of scenarios are to be considered. The first scenario refers to the spall repair due to routine wear and tear, freeze/thaw, and erosion; the other scenario is related to crater repair due to damage inflicted by incoming munitions. The latter is the more extreme case, as it represents an extreme event and the time to recovery in an uncertain environment must be as short as possible. In either circumstance, time expended to repair inflicted or cumulative pavement degradation is the main activity that causes interruption of vital airborne operations, and the goal of this topic is to identify superior expedient repair materials that will significantly shorten the time needed to restore minimal operating functionality.

Under the best possible post attack conditions, application, compaction and setting to load-bearing strength of asphaltic materials requires from 80 to 100 minutes. This time period includes material placement, compaction, and flooding the surface with water to accelerate the cooling process. The analogous procedure using a rapid-set Portland cement capping material requires approximately 120 minutes for placement and curing. The ideal product is a material that develops load supporting strength rapidly while allowing sufficient time for placement and work-up. The two key requirements are the limited time for placement and rapid strength development sufficient to support the designated aircraft load.

The target for this topic is a material and application process that will achieve performance equivalent to or better than the existing best material in 60 minutes or less. Selection factors include compatibility with existing construction equipment, logistical requirements, novelty and cost   Proposals based on warm mix asphalt will not be accepted.
 

PHASE I: Develop a paving material that has the ability to sustain aircraft traffic (equivalent to C-17) and has limited construction time up 75 minutes. Provide experimental evidence of the material strength development as a function of time.
 

PHASE II: Refine composition and delivery method to limit placement and cure time to 60 minutes or less from start of application. Prepare a “best” material composition for full-scale test section (at least 8 ft by 8 ft) application and traffic testing. Construction and traffic testing (with C-17 load cart) will be conducted at the Air Force Civil Engineer Center pavement testing facility. Cost analysis, product transition plan and environmental issues shall be included in Phase II.
 

PHASE III DUAL USE APPLICATIONS: Rapid pavement repair in support of timed military infrastructure recovery; commercial application in support of Transportation Agency maintenance practice for strategic roadways and runways supporting intense commercial activities and freights.
 

REFERENCES:

1. Lee, E.B., Lee, H., Akbarian, M. Accelerated Pavement Rehabilitation and Reconstruction with Long-Life Asphalt Concrete on High-Traffic Urban Highways, Transportation Research Record: Journal of the Transportation Research Board 2005, Volume 1905, pp. 56-64.
 

2. Shoenberger, J.E., Hodo, W.D., Weiss, C.A., Malone, P.G., Poole, T.S. Expedient Repair Materials for Roadway Pavements, ERDC/GSL TR-05-7, Geotechnical and Structures Laboratory, U.S. Army Engineer Research and Development Center, Vicksburg, MS, March 2005.
 

3. Vargas-Nordbeck, A., Timm, D. Validation of Cooling Curves Prediction Model for Nonconventional Asphalt Concrete Mixtures, Transportation Research Record: Journal of the Transportation Research Board 2011, Volume 2228, pp. 111-119.
 

4. Xiaojun, S., Selim, A., Lijun, S., Moisture Damage of Asphalt Mixes Modified with SEAM Pellets, Transportation and Development Innovative Best Practices 2008. April 2008, pp. 492-497.