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Archive: 2020
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  • Evaluation of Thin Flexible Pavements under Simulated Aircraft Traffic

    Abstract: A full-scale airfield pavement test section was constructed and trafficked by the U.S. Army Engineer Research and Development Center (ERDC) to evaluate the performance of relatively thin airfield pavement structures. The test section consisted of 16 test items that included three asphalt pavement thicknesses and two different aggregate base courses. The test items were subjected to simulated aircraft traffic to evaluate their response and performance to realistic aircraft loads and to evaluate the effect of reductions in tire pressure on thin asphalt pavement. Rutting behavior, pavement cracking, instrumentation response, and falling weight deflectometer response were monitored at selected traffic intervals. The results of this study were used to extend existing Department of Defense pavement design and evaluation techniques to include the evaluation of airfield pavement sections that do not meet the current criteria for aggregate base quality and minimum asphalt concrete surface thickness. These performance data were used to develop new aggregate base failure design curves using existing stress-based design methodology.
  • Environmental Quality Requirements Model Program Objective Memorandum Fiscal Years 2021–2025

    Abstract: This document describes the methodology used to evaluate the costs incurred by organizations involved in planning, programming, budgeting, and execution of the Army’s environmental programs and estimating those costs for future year planning cycles, this model is referred to as the Environmental Quality Requirements Model (EQRM). The EQRM is used to develop the budget positions as presented to Congress to obtain the Operations and Maintenance appropriations. These appropriations fund the Environmental Quality Program which includes Compliance, Conservation and Pollution Prevention requirements. The model encompasses the commands under the funding structure of the Deputy Chief of Staff – G9 Installations which includes the following: Installation Management Command, the Army National Guard, the Army Reserve Command, and the Army Materiel Command.
  • Vibration Survey of Room 47 with a Laser Doppler Vibrometer: Main Laboratory Basement, U.S. Army ERDC-CRREL

    ABSTRACT:  Plans are underway to create an acousto-optic laboratory on the campus of the Cold Regions Research and Engineering Laboratory. For this purpose, existing space in the basement of the Main Laboratory will be renovated. Demanding measurement techniques, such as interferometry, require a sufficiently quiet vibration environment (i.e., low vibration levels). As such, characterization of existing vibration conditions is necessary to determine vibration isolation requirements so that highly sensitive measurement activities are feasible. To this end, existing vibro-acoustic conditions were briefly surveyed in Room 47, a part of the future laboratory. The survey measured ambient noise and ambient vertical floor vibrations. The ambient vibration environment was characterized according to generic velocity criteria (VC), which are one-third octave band vibration limits. At the time of the survey, the ambient vibration environment fell under a VC-A designation, where the tolerance limit is 2000 µin/s across all one-third octave bands. Under this condition, highly sensitive measurement activities are feasible on a vibration-isolated working surface. The conclusion of this report provides isolation efficiency requirements that satisfy VC-E limits (125 µin/s), which are necessary for interferometric measurements.
  • Improving Design Methodologies and Assessment Tools for Building on Permafrost in a Warming Climate

    Abstract: The U.S. Department of Defense (DoD) operates numerous Arctic and Subarctic installations, including Alaska. Changes to permafrost can threaten critical built infrastructure. It is critical to accurately characterize and compare site conditions in permafrost regions to enable the efficient, cost-effective design and construction of an infrastructure well suited to the permafrost environment and that meets DoD requirements. This report describes three research efforts to establish (1) field investigation approaches for ground ice detection and delineation, (2) methods and modeling for early warning detection of thawing permafrost under infrastructure, and (3) an outline of a decision support system that determines the most applicable foundation design for warming and degrading permafrost. Outcomes of these interrelated efforts address needs to improve construction of DoD mission critical infrastructure on Arctic and Subarctic permafrost terrains. Field investigation processes used systematic methodologies including borehole data and geophysical measurements to effectively characterize subsurface permafrost information. The Permafrost Foundation Decision Support System (PFFDSS) tool implements and logically links field survey information and foundation type assessments. The current version of PFFDSS is designed to be accessible to design-engineers of a broad range of experience, that will reduce the effort and cost, and improve the effectiveness of site assessment.
  • Formulation of a Multi-Scale Watershed Ecological Model Using a Statistical Approach

    Abstract: The purpose of this special report is to provide a statistical stepwise process for formulation of ecological models for application at multiple scales using a stream condition index (SCI). Given the global variability of aquatic ecosystems, this guidance is for broad application and may require modification to suit specific watersheds or stream reaches. However, the general statistical treatise provided herein applies across physiographies and at multiple scales. The Duck River Watershed Assessment in Tennessee was used, in part, to develop and test this multiscale, statistical approach; thus, it is considered a case example and referenced throughout this report. The findings of this study can be utilized to (1) prioritize water-sheds for restoration, enhancement, and conservation; (2) plan and conduct site-specific, intensive ecosystem studies; and (3) assess ecosystem outcomes (that is, ecological lift) applicable to future with and without restoration actions including alternative, feasibility, and cost-benefit analyses and adaptive management.
  • Evaluation of New Endothall and Florpyrauxifen-benzyl Use Patterns for Controlling Crested Floating Heart and Giant Salvinia

    Purpose: The purpose of this research was to (1) evaluate concentration exposure time (CET) relationships for florpyrauxifen-benzyl (ProcellaCOR) for control of the floating leaved plant crested floating heart (Nymphoides cristata, CFH) and (2) evaluate foliar applications of endothall (Aquathol K) for control of CFH and the floating fern giant salvinia (Salvinia molesta).
  • Snow-Covered Obstacles’ Effect on Vehicle Mobility

    ABSTRACT:  The Mobility in Complex Environments project used unmanned aerial systems (UAS) to identify obstacles and to provide path planning in forward operational locations. The UAS were equipped with remote-sensing devices, such as photogrammetry and lidar, to identify obstacles. The path-planning algorithms incorporated the detected obstacles to then identify the fastest and safest vehicle routes. Future algorithms should incorporate vehicle characteristics as each type of vehicle will perform differently over a given obstacle, resulting in distinctive optimal paths. This study explored the effect of snow-covered obstacles on dynamic vehicle response. Vehicle tests used an instrumented HMMWV (high mobility multipurpose wheeled vehicle) driven over obstacles with and without snow cover. Tests showed a 45% reduction in normal force variation and a 43% reduction in body acceleration associated with a 14.5 cm snow cover. To predict vehicle body acceleration and normal force response, we developed two quarter-car models: rigid terrain and deformable snow terrain quarter-car models. The simple quarter models provided reasonable agreement with the vehicle test data. We also used the models to analyze the effects of vehicle parameters, such as ground pressure, to understand the effect of snow cover on vehicle response.
  • Long-Term Stability and Efficacy of Historic Activated Carbon (AC) Deployments at Diverse Freshwater and Marine Remediation Sites

    Abstract: A number of sites around the United States have used activated carbon (AC) amendments to remedy contaminated sediments. Variation in site-specific characteristics likely influences the long-term fate and efficacy of AC treatment. The long-term effectiveness of an AC amendment to sediment is largely unknown, as the field performance has not been monitored for more than three years. As a consequence, the focus of this research effort was to evaluate AC’s long-term (6–10 yr) performance. These assessments were performed at two pilot-scale demonstration sites, Grasse River, Massena, New York and Canal Creek, Aberdeen Proving Ground (APG), Aberdeen, Maryland, representing two distinct physical environments. Sediment core samples were collected after 6 and 10 years of remedy implementation at APG and Grasse River, respectively. Core samples were collected and sectioned to determine the current vertical distribution and persistence of AC in the field. The concentration profile of polychlorinated biphenyls (PCBs) in sediment pore water with depth was measured using passive sampling. Sediment samples from the untreated and AC-treated zones were also assessed for bioaccumulation in benthic organisms. The data collected enabled comparison of AC distribution, PCB concentrations, and bioaccumulation measured over the short- and long-term (months to years).
  • Magnetorheological Composite Materials (MRCMs) for Instant and Adaptable Structural Control

    Abstract: Magnetic responsive materials can be used in a variety of applications. For structural applications, the ability to create tunable moduli from relatively soft materials with applied electromagnetic stimuli can be advantageous for light-weight protection. This study investigated magnetorheological composite materials involving carbonyl iron particles (CIP) embedded into two different systems. The first material system was a model cementitious system of CIP and kaolinite clay dispersed in mineral oil. The magnetorheological behaviors were investigated by using parallel plates with an attached magnetic accessory to evaluate deformations up to 1 T. The yield stress of these slurries was measured by using rotational and oscillatory experiments and was found to be controllable based on CIP loading and magnetic field strength with yield stresses ranging from 10 to 104 Pa. The second material system utilized a polystyrene-butadiene rubber solvent-cast films with CIP embedded. The flexible matrix can stiffen and become rigid when an external field is applied. For CIP loadings of 8% and 17% vol %, the storage modulus response for each loading stiffened by 22% and 74%, respectively.