11 Aug 2025

3D Printing of Ultra-High-Performance Concrete: Shape Stability for Various Printing Systems

Abstract: Attention is on concrete 3D printing for its potential in structure optimization, life-cycle extension, emission reduction, and cost savings. Previous studies tailor a mix to a specific printing system and evaluate printability based on measurements of pumpability, extrudability, and buildability. For this investigation, an experimental program was conducted using various printing systems on a nano-modified UHPC mix. A medium-scale gantry and a large-scale ABB robotic arm were utilized, piston-type extruder and an auger system were employed, various nozzles, including circular and rectangular designs, were tested, and a cavity and Thom-Katt pump were used. Results indicated the shape stability of the UHPC mix is influenced by the printing system. Furthermore, the use of a circular nozzle demonstrated different shape stabilities when the extrusion system was changed from a piston-type extruder to an auger system. Additionally, the method of material pumping to the extrusion system was found to be critical for shape stability of printed layers. The mix failed to maintain its shape post-extrusion when using the cavity pump, which was attributed to higher strain rates imposed on material during the pumping process. This issue was not observed when the piston-type pump was used.

5 Aug 2025

Determination of Runoff Coefficient and Permeability of Airfield Matting (AM2) Long-Term Placement

Abstract: This report describes a small-scale water infiltration study of airfield mat-ting version 2 (AM2) at a test site on the US Army Engineer Research and Development Center’s Vicksburg, Mississippi, site. Before constructing AM2 runways, engineers must conduct a storm water drainage analysis; but no published study defining the runoff coefficient for AM2 exists. This study evaluated water infiltration of AM2 when subjected to 10-year and 100-year storm conditions from a proposed building site at Tyndall Air Force Base near Panama City, Florida. The allowable grade slopes for AM2 runways range from 1% to 3% in the longitudinal direction and 1% to 5% in the transverse direction. Multiple tests were conducted at various combinations of allowable grade slopes to determine grade slope orientation effects on AM2 runoff behavior. Runoff coefficients generally fell within the range of 0.05 to 0.10 for AM2. The highest runoff coefficients observed were within the range of 0.35 to 0.40 for a 5% transverse grade slope with a 1% longitudinal grade slope. Observation of the water infiltration behavior showed runoff increased with increasing transverse slope and de-creased with increasing longitudinal slope.

4 Aug 2025

Acoustic and Seismic Wave Transmission Throughout the Multidomain Environment: Experimental Design, Methods, and Construction of a Prototypical Littoral Zone

Abstract: The future operational environment is projected to be a multidomain, transparent battlefield in which the Army must be able to act as both a supported and supporting force. An accurate detection and interpretation of acoustic and seismic signals propagating across land-air-water (LAW) interfaces are required to meet future requirements of a fully “transparent” domain. The LAW domains converge at the significant contested littoral zones. Historically, interpreting signals crossing media boundaries has been studied by stovepiping each distinct medium. These fragmented perspectives led to discrepancies in boundary and adjacent media descriptions and media-specific governing physics. No comprehensive physics framework exists to accurately predict how disorderly waveforms freely traverse LAW media boundaries. To understand these complex phenomena, a highly controlled physical experiment was designed and implemented. Repeatable controls were conducted. Epistemic uncertainty was decreased, and high waveform fidelity was maintained in the experimental setup by not interfering with wave transmission or sensor accuracy between controls. This report summarizes the experimental design, implementation, challenges, and repeatability.

26 Jun 2025

Preliminary Study for Rapid Ground Stabilization

Abstract: The Army has a need to rapidly repair heavily damaged low-volume roads. This report describes the literature review, laboratory study, and preliminary technology evaluation for potential rapid road rehabilitation materials and equipment. The objective was to identify and evaluate equipment, materials, and techniques for rapid road repair. This phase of the study focuses on rapid stabilizers that, when added to native soil, could improve bearing capacity. Lightweight equipment and attachments were assessed for their ability to effectively excavate and place geomaterials. Several commercial soil stabilizers were identified that could meet strength requirements. Equipment attachments for a compact track loader were deemed most suitable for executing rapid repairs.

25 Jun 2025

Evaluating the Influence of Flexural Strength on Rigid Pavement Performance Under Simulated Aircraft Traffic

Abstract: A full-scale airfield pavement test section was constructed and trafficked by ERDC to investigate the impact of substandard flexural strength portland cement concrete on pavement structural support requirements under simulated aircraft loading conditions. The substandard pavements were representative of ones encountered in remote locations where there may be a lack of locally available competent materials, standard construction equipment, or a skilled labor force. The test section consisted of two PCC surface thicknesses constructed with a standard airfield flexural strength PCC mixture and a low flexural strength PCC mixture and a dowelled and non-dowelled joint. The test items were trafficked with a dual-wheel P-8 aircraft test gear mounted on a heavy-vehicle simulator. The outcomes of the tests showed a significant reduction in PCC pavement cracking performance resulting from the reduction in flexural strength. Instrumentation response data were analyzed to corroborate observed surface cracking. The field data were compared to DoD pavement design and evaluation procedures, and it found current procedures underpredicted observed performance in excess of 90 percent. These estimations may be overly conservative and may exceed a level of conservatism appropriate in a remote environment. The observed conservatism was attributed to simplifying assumptions and empirical correlations made in early development.

24 Jun 2025

A Field Sampling and Analysis Protocol for Assessing Occupational Exposure and Risk from Military Munition Storage Magazines

Abstract: An occupational health study was conducted inside reinforced-concrete earth-covered munitions storage magazines at Fort Wingate Depot Activity. HEPA vacuuming of bulk dust and wipe sample verification post-vacuuming was used. In Phase 1, no explosives detections exceeded site-specific screening criteria. In Phase 2, no exceedances were noted for detected explosives with criterion. Using structure/ reactivity characteristics within the explosives category, surrogates were assigned to the six explosives without occupational health screening criteria. Based upon structural similarities within the analysis category, assignments of surrogates to explosives without criteria did not adversely impact the conclusions. In Phase 1, lead was detected in bulk dust in all igloos, and all exceeded the applicable criterion for commercial/industrial workers. In Phase 2, all lead detections in wipe samples were below the wipe screening criteria. Results indicated the ECM interiors posed no unacceptable dermal occupational risk for explosives or lead residues following bulk dust removal. HEPA filter vacuuming of interior bulk dust in ECMs at FWDA reduced occupational risk/hazard for exposure via inhalation and dermal contact under worst-case exposure conditions. Both phases of sampling are widely applicable, provided the site-specific assumptions made for this study are evaluated for suitability to another specific application and adjusted if needed.

24 Jun 2025

Graphene-Coated Sand for Enhanced Water Reuse: Impact on Water Quality and Chemicals of Emerging Concern

Abstract: This paper investigates the potential of graphene-coated sand as an advanced filtration medium for improving water quality and mitigating chemicals of emerging concern in treated municipal wastewater, aiming to enhance water reuse. The study utilizes three types of sand coated with graphene to assess the impact of surface morphology, particle shape, and chemical composition on coating and filtration efficiency. Additionally, sand coated with graphene and activated graphene coated sand were both tested to understand the effect of coating and activation on the filtration process. The materials were characterized using digital microscopy, Raman spectroscopy, scanning electron microscopy, and X-ray diffraction analysis. The material’s efficiency in removing turbidity, nutrients, chemical oxygen demand, bacteria, and specific CECs was studied. Our findings indicate that GCS significantly improves water quality parameters, with notable efficiency in removing turbidity, COD, and bacterial contaminants. The study also highlights the material’s capacity to remove challenging CECs like Sulfamethoxazole and Diphenhydramine, showcasing its potential as a sustainable solution for water reuse applications. This research contributes to the field by providing a comprehensive evaluation of GCS in water treatment, suggesting its potential for removing CECs from treated municipal wastewater.

18 Jun 2025

Evaluation of Commercial Cementitious Rapid-Setting Materials and Testing Protocol for Repairing Airfield Spalls

Abstract: The Pavement Repair Material Certification Program assists the US Air Force Civil Engineer Center by executing independent testing on select commercial cementitious proprietary products to repair partial-depth spalls in airfield concrete pavements. The selection of cementitious rapid-setting repair products can be difficult for military personnel considering the number of commercially available proprietary products. Too often, many product manufacturers highlight product strengths while masking undesirable properties. The purpose of this research was to evaluate selected commercially manufactured cementitious products through a series of laboratory testing protocols. These protocols were established to aid airfield managers and repair teams in selecting optimal airfield pavement spall repair materials by maintaining a database of approved products. Under the program, approximately four to six repair products are tested annually. This report presents the laboratory test methods and results of cementitious rapid-setting repair products tested at the US Army Engineer Research and Development Center from 2018 to 2022. The report also evaluates the overall test methods for assessing a material’s suitability for airfield spall repairs. Using the laboratory evaluation, eight products were identified as compatible for partial-depth airfield pavement concrete spall repairs.

16 Jun 2025

Evaluation of Tekcrete Fast for Airfield Pavement Repairs

Abstract: Tekcrete Fast is a deployable, high-strength cementitious product with rapid bonding force that was initially developed to provide stability for structures damaged by seismic activity and explosives. The product was evaluated by researchers at the US Army Engineer Research and Development Center for its ability to execute necessary force projection and resilient infrastructure repairs for the US military without major negative impacts to the mission. Full-scale testing of the rapidly emplaced calcium-sulfoaluminate (CSA) concrete product was completed to identify the sustainability and strength of the material with military aircraft traffic. The CSA concrete mixture was designed for dry-mix shotcrete applications and adapted to be placed conventionally (cast-in-place) using a portable skid steer concrete mixer. This report presents a technical evaluation of the field performance of full-depth concrete repairs conducted using the cast-in-place Tekcrete Fast material in a portable concrete mixer. Passes-to-failure rates for each repair were determined using an F-15E load cart. Results indicated that Tekcrete Fast meets the military’s criteria for being an expedient pavement repair solution.

13 Jun 2025

Enhanced Route Reconnaissance—Generation 1

Abstract: The movement of soldiers and materiel across battlespace is critical to a successful military operation. Knowledge of the road network condition ensures safe and successful vehicle maneuver. This research focused on remote assessment of poor-quality paved road networks for vehicle maneuver using data products derived from three-dimensional point clouds. Point clouds were generated from lidar sensors deployed from ground and airborne platforms to enable engineering analysis of the pavement surface. A series of algorithms developed to extract roughness, grade, radius of curvature, and width along the road network ensured storage of information for graphical display. A vehicle speed lookup table was calculated by conducting computer simulations using the NATO Reference Mobility Model over a range of road parameters. The lookup table enabled determination of the maximum allowable speed for a given vehicle type associated with the extracted road parameters. A graphical interface, developed for displaying the percentage speed reduction as either red, amber, or green squares along the road network, provided visual assessments of road condition. This report summarizes developing a software suite to calculate and visualize speed reduction over a road network as a function of route geometry, condition, and vehicle type. The interface developed can aid in critical logistical decisions that influence the success of military maneuver operations.