Improved Laboratory Testing Protocol and Full-Scale Evaluation of Rapid-Setting Cementitious Repair Products for Airfield Repairs.

Many transportation management agencies require premixed rapid-setting cementitious repair products that can be easily mixed and placed to return airport and roadway facilities to service and prevent downtimes. The US Air Force Civil Engineer Center oversees a rapid-setting cementitious material certification program to assist airfield managers and repair teams in selecting commercially available proprietary products to repair spalls in airfield concrete pavements. The program includes critical performance tests, such as compressive strength, flexural strength, and set time, as well as tests to evaluate each product's long-term resistance to more environment-based distress. One potential issue with the use of rapid-repair products is that they can become brittle and prone to cracking, causing potential foreign object debris (FOD) damage to aircraft. Proprietary products offer high early strengths, quick set times, and the ability to withstand traffic for many years. These products evolve, and new or modified products must be properly evaluated to ensure that they do not fail under traffic and that they can be placed without reaching the initial set prematurely. For this effort, the existing US Department of Defense (DoD) laboratory test protocol was evaluated by performing multiple tests on 25 repair products. Eleven products were also used to conduct permanent and emergency spall repairs that were load tested with simulated aircraft traffic to assess the protocol's effectiveness in identifying quality rapid-setting repair products. Larger emergency repairs (approximately 2.4×2.4 m) were also conducted with three products and load tested. Overall, several changes to the laboratory protocol were recommended, but full-scale tests indicated that the recommended protocol is still effective for selecting quality products. Larger emergency repair test results indicated that rapid-setting repair products can be effective for these size repairs, but the need for full-scale testing before certification was heavily emphasized. Practical Applications: The newly modified protocol for evaluating rapid-setting cementitious repair products in the laboratory is expected to have immediate use for airfield repair practitioners. There are many commercially available products, and the ability to identify high-performing products via a suite of laboratory tests should help extend the life of airfield repairs. In addition, the emergency spall repair and emergency large repair techniques discussed in this paper could be useful for civilian airport repair applications, where downtimes are very limited due to very full flight schedules. Conducting a very quick repair with high-quality materials can maintain flight operations until a more permanent repair can be conducted. [ABSTRACT FROM AUTHOR]