7 Mar 2025

Coupling Electrokinetics and Phytoremediation to Remove Uranium from Contaminated Soil: A Laboratory Pilot-Scale Study

Abstract: Uranium is a naturally occurring trace element and radionuclide. Uranium is introduced to the environment anthropogenically because of industrial, military, and nuclear energy activities. The approach of coupled electrokinetic phytoremediation has been used to remove other heavy metals from contaminated soil. The objectives here are to investigate the distribution and solubility of uranium in soils with UO2, UO, and uranyl, and examine the processes of coupled electrokinetic phytoremediation in removing U from soils with perennial ryegrass at a laboratory pilot scale. A low-intensity direct electric current field was applied to the contaminated soil for 7 d at 8 h·d−1 after ryegrass was grown for 2 weeks, then, polarity reversal was employed for another 7 d at 8 h·d−1. The uranium redistribution took place among various solid-phase components due to changes in the pH and chemistry of the electrolyte solution. The electrokinetic field increased the U bioavailability in soils as water-soluble U and exchangeable U in contaminated soils with all U species. Thus, the EKF significantly increased the U uptake and bioaccumulation by ryegrass. The current laboratory pilot-scale test confirmed our previous observation from the pot greenhouse study–the coupled electrokinetic phytoremediation may have potential for application in remediating U-contaminated sites.

6 Mar 2025

Effect of Fighter Aircraft Traffic on Full-Depth Reclamation with Thin Surface Layers

Abstract: The US Army Engineer Research and Development Center (ERDC) constructed a full-scale test section to evaluate the effectiveness of different pavement surface technologies in sustaining fighter aircraft traffic. A deteriorated thin asphalt pavement was recycled utilizing full-depth reclamation (FDR) techniques with cement stabilization. Relatively thin surfacing solutions constructed with either conventional hot mix asphalt (HMA) or nontraditional surface materials were placed on the FDR layer and trafficked with a single-wheel F-15 load cart. Rutting behavior, instrumentation response, and nondestructive evaluation measurements were monitored during traffic. Experimental results showed that thin surface treatments and microsurfacing materials placed on FDR layers were capable of supporting an extremely limited number of F-15 operations, and the generation of foreign object debris (FOD) was a major concern. A 4 in. thick HMA layer was required to sustain a meaningful number of F-15 operations, that is, approximately 3,000, and a 2 in. thick HMA layer was required to sustain approximately 100 F-15 passes. An analysis using the Airfield Pavement Evaluation subroutine in PCASE suggested that existing stabilized equivalency factors were reasonable when the minimum asphalt layer thickness was specified. A reduced equivalency factor was observed when the asphalt layer thickness was less than the minimum thickness.

6 Mar 2025

New Construction Criteria for a Changing Arctic and Subarctic: The UFC 3-130 Series Revision Process

Abstract: The DoD operates significant and strategically important installations in the Arctic and Subarctic domain. Geopolitical, economic, and climatic changes require an upgraded ability to rapidly deploy and sustain forces into Arctic and Subarctic regions. Relevant engineering criteria and guidance to support these efforts are the Unified Facility Criteria 3-130–Arctic and Subarctic Construction (UFC 3-130) documents, originally a seven-volume series. The series has been ‘inactive’, indicating the specifications are not current and potentially technically noncompliant. Therefore, designers may resort to methods that do not meet current military or civilian standards, or they may use the outdated guidance leading to costly design and construction failures. Infrastructure owners and operators must be confident that up-to-date technology and criteria are specified to ensure life safety, mission readiness, and infrastructure longevity. This report highlights the process and resources used to generate a new five-volume UFC Arctic and Subarctic series that aligns with current technology and standards while also addressing a changing climate. These new documents are appliable for use by planners, engineers, and architects when planning, designing, constructing, and maintaining DoD infrastructure. The full UFC 3-130 series is available on the Whole Building Design Guide (WBDG) website at https://www.wbdg.org/dod/ufc.

6 Mar 2025

Norfolk Harbor Navigation Improvements Project: Modeling of Dredged Material Placement Schemes and Long-Term Sediment Transport at the Dam Neck Ocean Disposal Site

Abstract: US Army Corps of Engineers–Norfolk District requested assistance with the development and evaluation of dredged-material-placement schemes that evenly distribute placed material and avoid or minimize unacceptable mounding in accordance with the site management and monitoring plan. A multiple placement fate and transport modeling study was conducted to determine the optimal placement plan for dredged material from Thimble Shoals Channel and Atlantic Ocean Channel at the Dam Neck Ocean Disposal Site (DNODS). Provided the large volume of dredged material to be placed at DNODS over a short duration during the construction period, a modeling study was performed using the Geophysical Scale Multi-Block (GSMB) modeling system to determine the transport and fate of placed dredged material at the DNODS that is resuspended by currents and waves over a 2-year period. Six scenarios were undertaken to determine the best path forward. Scenarios 1 and 4 were excluded due to high exceedance of the depth threshold. Scenarios 2, 3, 5, and 6 yielded an approximate 1%–2% dispersal of placed materials from the DNODS during ambient environmental conditions; Scenario 6 yielded the least. Most dispersion occurred during two simulated hurricanes. The model findings generally support the DNODS Environmental Impact Statement and site-designation documents.

3 Mar 2025

Low-Sill Control Structure: Physical Modeling Investigation—Potential Upstream Dike Fields

Abstract: The model investigation reported herein describes the process to analyze the effects of proposed dikes in various locations upstream of the Low-Sill Control Structure (LSCS) using an existing 1:55 Froude-scaled physical model. The purpose of this effort was to utilize the physical model to explore potential configurations of river-training structures in the approach channel that would result in more uniform flow conditions at the structure. This analysis was conducted by constructing dikes out of both sandbags and rock. Each dike configuration was surveyed using lidar and then tested by collecting particle-tracking velocimetry data. A total of nine dike configurations were tested in the physical model, and the resulting flow fields in the approach channel were provided to the US Army Corps of Engineers, Mississippi Valley Division. Most configurations resulted in data that showed improved, straighter flow paths in the approach channel. The results of these tests indicated that an L-head dike configured as the 50 ft stone dike 1-23A provided relatively straight flow conditions approaching the LSCS with relative uniform velocities across the channel.

3 Mar 2025

Full-Depth Reclamation Equipment Evaluation and Expedient Pavement Reconstruction Process Development

Abstract: Full-depth reclamation (FDR) is a rehabilitation approach that can be readily applied to rapidly restore the structural capacity of heavily distressed or structurally deficient airfield asphalt pavements. This report presents a market survey of compact FDR construction equipment that could be deployed in contingency environments. Current equipment inventories from the US Air Force and Marine Corps were reviewed to identify gaps in terms of equipment for pavement reconstruction via the FDR technique. Additionally, a field demonstration was conducted to assess the effectiveness and productivity of FDR reclaimers on representative airfield asphalt pavements. A preliminary reconstruction process and a spreadsheet based calculator were developed to estimate construction times for the FDR technique. Examples of pavement reconstruction scenarios were generated to illustrate the FDR process as well as identify an approach with optimized construction times. The information in this report aims to assist in the implementation of reconstruction specifications for the FDR technique as applicable to expedient construction projects in contingency environments.

28 Feb 2025

The 2023 Joint Airfield Damage Repair Symposium (JADRS) at Fort Liberty, North Carolina

Abstract: The US Army Engineer Research and Development Center (ERDC) and the 20th Engineer Brigade, 27th Engineer Battalion, executed the Joint Airfield Damage Repair Symposium from 5 to 14 June 2023. The event was a training experience for personnel executing pavement-repair tasks and a planning and coordination exercise for senior military and civilian leaders developing technologies and plans for airfield damage repair (ADR). The participants included 14 trainers, 8 staff members, 48 observers, and 145 trainees from the US Army, Air Force, Navy, and Marines. The Military Occupational Specialty of most Army trainees was 12N, Horizontal Construction Engineer. The symposium also included a workshop attended by more than 20 organizations representing all branches of the US Military. Breakout sessions were used to develop strategies to address gaps in ADR materials, training, and doctrine. At the end of the symposium, the 27th Engineer Battalion identified needs for an updated joint doctrine detailing the capabilities residing within each service branch and defining their roles and responsibilities, equipment up-grades based on commercially available products that would enhance efficiency for ADR missions, positioning ADR materials in strategic locations to reduce the logistical burden of delivery, and lighter, more expeditionary ADR kits across each service.

28 Feb 2025

Repair of Damaged Continuity Joints Using Ultra-High Performance, Fiber Reinforced Self-Consolidating, and Magnesium–Aluminum–Liquid–Phosphate Concretes

Abstract: Bridge elements known to develop damage over time are individual continuity joints connecting girders. Replacing damaged joints is an expensive and invasive process and a need exists to design a less invasive repair method. This study focused on evaluating an encapsulation repair method for continuity joints that would not require extensive demolition of the bridge deck to implement and could potentially be constructed without bridge closure. Approximately half scale connected bridge girder specimens were constructed and purposely damaged to create similar crack patterns to those seen in bridges. Once damaged, a set of three specimens was repaired using the encapsulation method with three different high performance materials, ultra-high performance concrete (UHPC), fiber reinforced self-consolidating concrete (FRSCC), and magnesium–aluminum–liquid–phosphate (MALP) concrete. Of the three repaired specimens for each material, one was tested in positive moment bending and two in negative moment bending, similar to in situ conditions. The results appear to indicate that using each of the tested materials as an encapsulation repair for damaged continuity joints is viable to re-establish continuity and load capacity. However, the UHPC repairs’ resistance to cracking could indicate the best performance by further protecting the continuity joint reinforcing steel from water ingress.

26 Feb 2025

Demonstration of Photocatalytic Degradation of Per- and Polyfluoroalkyl Substances (PFAS) in Landfill Leachate Using 3D Printed TiO2 Composite Tiles

Abstract: Per- and polyfluoroalkyl substances (PFAS) are recalcitrant substances present globally in many landfill wastewater leachates and have potential ecological and human health risks. Conventional treatment technologies have shown limited efficacy for many PFAS due to the stable C–F bonds. Therefore, there is growing interest in applying advanced oxidation processes to decrease the aqueous concentrations in contaminated wastewater and mitigate risks. The goal of this study was to evaluate the photocatalytic performance of treating PFAS in landfill leachate using a novel photocatalyst composite. Treatment structures were fabricated using polylactic acid and compounded with TiO2, and 3D printed into tiles. A pilot-scale treatment system was designed to promote photocatalysis using 3D composite structures and UV irradiance intensity of 1.0 mW cm−2 following 24- and 36-h hydraulic retention times. Photocatalytic degradation was achieved for seven of the 11 PFAS evaluated in this study. Greater than 80% removal of PFOS, PFNA, PFDA, and PFOSAm was observed after 24 h of photocatalysis. These results indicate photocatalysis using TiO2 polymer composites can achieve beneficial levels of PFAS degradation. This study provides a proof-of-principle approach to inform the application of additive manufacturing of photocatalytic composites for use in the treatment of PFAS-contaminated wastewater.

25 Feb 2025

The Design of Multimedia Object Detection Pipelines within the HPC Environment

Abstract: Computer vision multimedia pipelines have become both more sophisticated and robust over the years. The pipelines can accept multiple inputs, perform frame analysis, and produce outputs on a variety of platforms with near-real-time performance. Vendors such as Nvidia have significantly grown their framework and library offerings while providing tutorials and documentation via online training and tutorials. Despite the prolific growth, many of the libraries, frameworks, and tutorials come with noticeable limitations. The limitations are especially apparent within the high-performance computing (HPC) environment where graphic processing units may be older, user-level rights more restricted, and access to the graphical user interface not always available. This work describes the process of building multimedia object detection and segmentation pipelines within the HPC environment, its challenges, and ways to overcome the shortcomings. The project describes an iterative design process, which can be used as a blueprint for future development of similar computer vision pipelines within the HPC hosting environment.