Both civilian and military airfield managers require the safe operation of aircraft on runway surfaces. This includes the operation of ground traffic on airfield operating surfaces as well as connecting road infrastructure. Often times in austere environments, this road infrastructure is unpaved and consists mostly of either semiprepared or unbound soils. It has been shown in numerous research efforts that surface friction is an excellent indicator of safe operating conditions. Although a great deal of work has been done to quantify safe surface conditions for landing and takeoff operations on rigid and flexible pavement structures, limited research exists to extend such efforts to soil-based or semiprepared surfaces. The objective of this research was to develop deceleration-based surface friction prediction models on unpaved surfaces with varied moisture conditions and soil types. Surface friction, in this study, was quantified using the Findlay Irvine Mk2-D GripTester. Deceleration was measured using four smartphone inertial measurement units (IMUs), one Bowmonk IMU, and one Xsens IMU. Tests were conducted in three ground vehicles: a high-mobility multipurpose wheeled vehicle, a civilian ½-ton pickup truck, and a civilian full-size sport utility vehicle. The various deceleration-based devices tested here adequately correlated (coefficient of determination >0.6) with Mk2-D GripTester measurements collected on unpaved soil runways. The models and measurement methods detailed here are of considerable use to both semiprepared runway and ground vehicle operations managers around the world needing to measure safe surface conditions following inclement weather.

The U.S. Army Engineer Research and Development Center (ERDC) has developed a method for predicting surface friction response by use of ground vehicles equipped with deceleration-based measurement devices. Specifically, the ERDC has developed models and measurement methods between the Findlay Irvine Mk2 GripTester and a variety of deceleration measurement devices: Bowmonk AFM2 Mk3, Xsens MTi-G-710, two Android smartphones, and two iOS smartphones. These models show positive correlation between ground vehicle deceleration and fixed-slip surface continuous surface friction measurement. This effort extends prior work conducted by the U.S. Army ERDC in developing highly correlative models between the Findlay Irvine Mk2 GripTester and actual C-17 braking deceleration, measured via the runway condition rating (RCR) system. The models and measurement methods detailed here are of considerable use to semi-prepared airfield managers around the world needing to measure safe landing conditions following inclement weather. This work provides the tools necessary for airfield managers to quantify safe landing conditions for C-17 aircraft by using easily obtainable equipment and simple test standards.

The U.S. Army Engineer Research and Development Center recently began a research project to evaluate pavement preservation techniques for asphalt pavements on Army airfields. Three field sites were selected for testing. Field sites represented the following climatic regions: hot and wet, hot and dry, and cold. Each of the test sites was on a taxiway or parking apron pavement on an Army airfield. Commercially available products marketed for pavement preservation were placed at each site. Existing pavements were in good condition, and all exhibited only minor longitudinal or transverse cracking and limited weathering. Preliminary data were collected by evaluating pavement surface properties and by extracting pavement cores prior to placement of the surface treatment. Additional tests were performed after product placement. Annual evaluations will provide comparable data to quantify the benefit of the treatment based on its ability to reduce environmental distresses. This report provides information on the products placed at each site as well as pavement conditions before product placement.

Maintenance and repair activities are critical to economically and efficiently sustain airfield operations with existing pavement infrastructure. Repairing spalls in Portland cement concrete (PCC) pavements is a common work activity used to reduce the costs associated with aircraft damage and prolong the service life of the pavement further reducing the life-cycle costs for the pavement structure. Costs decrease dramatically for every additional year of pavement use that does not cause vehicle damage or require repeated patching or full slab replacement.Traffic performance of fourteen different concrete repair products was evaluated for repairing spalls in PCC airfield pavement. The objective of this study was to identify within these products suitable repair materials for long-term concrete spall deficiency repairs.Numerous partial-depth repairs were constructed along joints and in the interior of the test slab and backfilled with the repair products following the manufacturer requirements. After the material cured to the minimum required by each manufacturer, the repairs were trafficked with simulated F-15E aircraft traffic to monitor their long-term performance over successive aircraft loadings. The field evaluations of the selected repair products considered how well each product performed under simulated F-15E traffic as well as the ease of mixing, placing, and finishing.

The U.S. Army Engineer Research and Development Center (ERDC) solves the nation's toughest engineering and environmental challenges. ERDC develops innovative solutions in civil and military engineering, geospatial sciences, water resources, and environmental sciences for the Army, the Department of Defense, civilian agencies, and our nation's public good. Find out more at www.erdc.usace.army.mil.