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.

19 Feb 2025

Autonomous Cyberdefense Introduces Risk; Can We Manage the Risk?

Abstract: We discuss the human role in the design and control of cyberdefenses. We focus on machine learning training and algorithmic feedback and constraints, with the aim of motivating a discussion on achieving trust in autonomous cyberdefenses.

19 Feb 2025

The Geophysical Survey of Mare Island Naval Cemetery, California

Abstract: The US Congress codified the National Historic Preservation Act of 1966 (NHPA), the nation’s most effective cultural resources legislation to date, mostly through establishing the National Register of Historic Places (NRHP). The NHPA requires federal agencies to address their cultural resources, which are defined as any prehistoric or historic district, site, building, structure, or object. Section 110 of the NHPA requires federal agencies to inventory and evaluate their cultural resources, and Section 106 requires them to determine the effect of federal undertakings on those potentially eligible for the NRHP. This project was undertaken to provide the US Department of Veterans Affairs (VA), National Cemetery Administration (NCA), with a geophysical survey of Mare Island Naval Cemetery. The approximately 2.5-acre cemetery is located in Vallejo, California, and contains more than 900 burials. Mare Island Naval Cemetery is part of the Mare Island Naval Shipyard Historic District, which was listed concurrently on the National Register of Historic Places and as a national historic landmark in 1975.

19 Feb 2025

Lower James River Sediment Transport Modeling: Jordan Point

Abstract: US Army Corps of Engineers–Norfolk District (NAO) requested assistance from the US Army Engineer Research and Development Center (ERDC) to examine currently used placement sites within the James River, Virginia, initiative area, determine potential risk to critical environmental receptors during placement, and predict the life cycle of the placement sites. The focus of the analysis within this work is the Jordan Point placement site. The far-field, fate-transport modeling at Jordan Point shows relatively low maximum values of suspended sediment concentration (less than 40 mg/L) and deposition values (less than 0.2 cm). Material that is placed at Jordan Point appears to quickly disperse through the system, depositing in thin layers at specific areas. The life-cycle analysis performed for the Jordon Point placement site yielded an estimated useable project life of the Jordan Point placement sites of 26 years with an uncertainty of ±4 years. Analysis showed that 97% of the net sediment deposition in the navigation channel in proximity to this site is from the upper James River, 2% is from downstream sources, and 1% is from the two Jordan Point placement sites.

19 Feb 2025

Exploring the Convergence of Resilience Processes and Sustainable Outcomes in Post-COVID, Post-Glasgow Economies

Abstract: Resilience and sustainability have each offered a path forward for post-COVID economic recovery and a post-Glasgow global financial order. Yet, the relationships between these two concepts are largely unexplored in economic policy and investment strategies. In light of emerging systemic risks and global demands for more resolute investments in resilience and sustainability, this perspective article took the position that policymakers must begin to draw greater conceptual, empirical, and practical linkages between sustainability and resilience. This perspective article provided a simplified framework for understanding the positively reinforcing, negatively conflicting, and neutral relationships between different types of resilience and sustainability consistent with two propositions. The Reinforcement Proposition argues (i) that various resilience processes may drive sustainable outcomes, and/or (ii) that an allocation of sustainable resources may reinforce resilience processes, as well as the transformative adaptation of markets. Conversely, the Conflict Proposition argues (i) that certain resilience processes may perpetuate stability features that may thwart an economic transition toward sustainability, and/or (ii) that certain sustainability outcomes associated with reorganized economic structures and relationships may undermine resources for resilience. This framework provides policymakers with an opportunity to evaluate the convergent and conflicting trade-offs of resilience processes and sustainable outcomes.

18 Feb 2025

Birds Not in Flight: Using Camera Traps to Observe Ground Use of Birds at a Wind-Energy Facility

Abstract: Camera trapping is increasingly used to collect information on wildlife occurrence and behaviour remotely. This provides insights into habitat use by species of interest and gathers information on non-target species. We implemented ground-based camera trapping to investigate behaviours of ground-dwelling birds and to monitor activities of Agassiz’s desert tortoises at their self-constructed burrows in a wind-energy facility near Palm Springs, California. While doing so, we collected data on numerous burrow commensals, including birds. Monitoring from late spring to mid-autumn showed regular use of tortoise burrows by 12 species of birds, the most abundant being the rock wren. Birds appeared to use the interior or vicinity of burrows for gathering nesting material, displaying, feeding, dust bathing and other activities. Of the species observed, 10 are known to be occasional casualties of turbine-blade strikes. Using camera traps focused at ground level can be a useful tool in avian conservation effort for measuring bird presence, activity and behaviour in altered habitats. Acquiring data over the long term by using ground-based monitoring with camera traps could add to our understanding of avian behaviour and habitat use in relation to wind-energy infrastructure and operations, and help determine the vulnerability of avifauna utilizing the area.