Laboratory Evaluation of Expedient Low-Temperature Admixtures for Runway Craters in Cold Weather

The research included in this report investigates admixtures that can improve the low-temperature early strength gain performance of two products already in existence (which are currently in limited use by the Air Force) for hasty runway repair. The first product, a “flowable fill,” is a low-level cementitious sandy mixture used to rapidly fill the bulk of a runway crater; the second product, a rapid setting concrete, seals the final 10–12 in. of the crater and allows heavy-vehicle trafficability. The primary operational requirements, which the current two-part solution meets at higher temperatures (greater than 10°C) but which require improvements at lower temperatures (−10°C to 10°C), involve time of set and 2 hr unconfined compressive strength (UCS). This research ignores typical concerns, such as long-term durability, aesthetics, and corrosion, that are of minimal importance in this expedient field-use application—horizontal surface repairs not expected to last more than two to five years. Results from this study are expected to be incorporated into operational testing, using Air Force equipment, personnel, and techniques, for small and large crater repair at sub-freezing temperatures. This report describes laboratory tests to improve the early strength gain performance of both repair materials to repair small-to-large craters at ambient temperatures of −10°C to 10°C.