Full-scale study in controlled conditions
The Frost Effects Research Facility (FERF) is the largest refrigerated warehouse in the United States that can be used for a variety of roadway and pavement, geotechnical and other investigations at sub-freezing temperatures year-round. Tests can be conducted using a combination of ambient and ground temperatures from approximately 20°F to 80(+)°F year-round, with the ability to conduct accelerated pavements testing and evaluation due to the effects of repeated freezing and thawing.
On-hand equipment to support non-destructive pavements investigations includes a 20-ton crane on a monorail, a falling weight deflectometer (FWD) and a heavy weight deflectometer (HWD), a heavy vehicle simulator (HVS) to rapidly replicate a large number of passes by typical highway traffic loads, and other equipment.
In addition to controlling temperatures, testing can incorporate controlled moisture conditions and use a variety of specific sub-grade materials.
As an example of the FERF’s flexibility to accommodate a wide range of RDT&E investigations, the facility will soon house a 50-ft wave tank in the Southeast quadrant to study sea-ice interactions with waves and petroleum products, with wider temperature ranges and other additional testing additional capabilities.
Unique research and testing facility
Previous studies include American Association of State Highway and Transportation Officials (AASHTO) subgrade study, U.S. Air Force Airfield Damage Repair at sub-freezing temperatures using novel concrete and flowable fill materials, University of Alaska Pile Creep Study, Montana State University pavement geo-reinforcement study, and evaluation of mine detector and ground penetrating radar capabilities and limitations for Night Vision and Electronic Sensors Directorate (NVESD).
The U.S. Air Force frequently encounters damage to airfields and other pavements due to a variety of threats in contingency environments. In these situations, the primary focus is speed—minimal time for Airmen preparation, materials acquisition, materials setting and strength gain, and results variability due to physical security considerations and other practical environmental constraints.
ERDC responded to the Air Force’s needs by developing novel flowable fill and rapid setting concrete materials, focusing on speed and meeting other constraints: easy to use materials with a long shelf life, simple mixing procedures, rapid strength gain, compatible with existing Air Force equipment (Simplified Volumetric Mixer), compatible with sub-freezing temperatures (ground, ambient), and simple Airmen QA/QC procedures. These materials achieve full strength in 2–3 hours at 23°F compared with at least 7 days for conventional materials at moderate temperatures. These materials save time and money, reduce site exposure, and are user-friendly. The FERF was critical to the project’s success in Spring 2013 by allowing full-scale (100 ft) runway testing with controlled ground and ambient temperatures.
- The 29,000 sq. ft. facility includes
- four independent test sections (SW, NW, NE, SE), each approximately 100 ft. in length, with additional sub-divisions possible;
- 50 ft. wide x 14 ft. tall equipment entrance doors for partial or complete opening;
- 7 personnel refrigeration doors throughout the building;
- an indoor materials staging area (50 ft. x 20 ft.) with forklift loading door (10 ft. wide x 10 ft. height); and
- a variety of amenities, including office space and control room with dual network connectivity, restrooms, basement access surrounding the facility for controls and refrigeration access.
- Supporting equipment includes
- a 20-ton monorail crane with minimum 15 ft. ground clearance (minimum at South entrance), spanning 200 ft indoors (all of south sections, majority of north sections) and extending 30 ft onto the south loading apron;
- a Heavy Vehicle Simulator (HVS) for simulating a large volume of highway vehicle loading in a short time period on flexible or rigid pavements. The HVS is capable of approximately 14,400 passes in 24 hours in uni-directional mode (load applied in one direction, then return HVS to start and repeat), 25,000 passes in 24 hours in bi-directional mode, and 20 years of equivalent traffic in only 6 months. The wheel load varies from 20 to 100 kN (4.5–22.5 kips), and its configuration takes advantage of the symmetry of truck or aircraft tire configurations. The HVS simulates half of one axle; for example, a 9 kips (1 kip = 1000 lbs) load represents a standard truck axle load of 18 kips. Multiple tire types can be used, to include truck tires (with pressure from 560–690 kPa or 80–100 psi) and C-141 aircraft tires (with pressure up to 1450 kPa or 210 psi). The effective length of traffic is 20 ft in addition to approximately 3 ft. for acceleration and deceleration at the ends of the effective test window. The width of the test window depends on the tire configuration used. The tire traffic can be wandered to simulate real traffic. Including traffic wandering, a typical width of the traffic window is 3 ft.
- a Dynatest heavy weight deflectometer (HWD) for non-destructive testing and evaluation of rigid (concrete) pavements using a peak load of 30 to 240 kN (6,500 to 54,000) lbf;
- a Dynatest falling weight deflectometer (FWD) for non-destructive testing and evaluation of flexible pavements using a peak load of 7 to 120 kN (1,500 to 27,000) lbf;
- a van for towing and controlling either the HWD or FWD on or off campus, with a customized pickup truck targeted to soon replace the van;
- easy accommodation of additional equipment and capabilities of the abutting Materials Evaluation Facility (MEF) for snow, ice production, lower temperatures, and other testing capabilities; and
- other supporting equipment. See facility manager for details.
- Ambient temperature: 20°F–80(+)°F year round in normal operations enabled by a 70-ton refrigeration system pushing -20°F through 10 air handler units, which double as heating units (for defrost and for heating the facility seasonally). See facility manager for additional capabilities that are possible seasonally in certain sections of the FERF or by using some additional equipment and setup procedures.
- Ground temperature: 10 ft. x 10 ft. ground cooling panels used alone or in series (connect up to 20 in series simultaneously; 40 total on hand) to completely cover one test section and rapidly freeze any ground surface (pavement, sub-grade). The ground panels circulate glycol at -20 °F to rapidly cool any ground surface. As a rule of thumb, the panels can push frost depth approximately one inch per day, though actual results vary (initial frost depth penetration is faster and then slows with depth; varies by material type and is much faster when applied to concrete and course aggregate; and other variables).
- Remote video, photo, and controls monitoring in real-time with a dedicated, secure FERF website
- Ambient and ground temperature monitoring in real time in the office / control room or remotely with customizable graphs and other functionality through LabView
- Other instrumentation available; see Facility Manager for details
Work with Us
Our capabilities and facilities are available to assist you in addressing and solving a variety of cold regions science and engineering challenges. Please consult the Facility Manager below for facility usage and rates information, which vary depending on the type of activity and support needed. The Facility Manager can also provide additional documentation.
Engineering Resources Branch (CEERD-RV-E)
US Army Engineer Research and Development Center | Cold Regions Research and Engineering Laboratory