23 Sep 2025

Naval Expeditionary Runway Reconstruction Criteria: Evaluation of Full-Depth Reclamation for P-8 Aircraft Operations

Abstract: A structurally failed asphalt pavement section was reconstructed to investigate the full-depth reclamation (FDR) technique. The full-scale FDR pavement section consisted of six different test items containing different FDR material blends, a minimum asphalt layer thickness (i.e., 2 in. and 3 in.), and FDR-surface pavements (i.e., asphalt-surfaced and unpaved pavements). The FDR layers were stabilized with a combination of an asphalt emulsion and Portland cement. A heavy vehicle simulator was employed to simulate the loading conditions of the P-8 Poseidon aircraft. The performance of the full-scale pavement section before and after the FDR reconstruction was compared. The FDR technique was satisfactorily implemented to restore the structural capacity of a failed asphalt pavement. The pavements with FDR layers yielded at least two times more allowable passes than the conventional pavements. The FDR-surface pavement sections also demonstrated structural competency to support the expedient operation of heavy aircraft. The performance data generated from this project must be implemented to improve current practices in the design and evaluation of airfield asphalt pavements containing an FDR layer.

19 Sep 2025

Bridging the Impact Response of Polymers from the Nanoscale to the Macroscale

Abstract: Impact from a fast-moving object is a common event, but it can vary greatly in terms of scale, speed, and energy depending on the specific case. Recently, it has been suggested that scaling analysis can be used to relate the impact performance of materials at the nano- and microscale to their behavior at the macroscale, which is relevant for most applications. In this study, we explore the broad applicability of this approach by conducting micro- and macroprojectile impact tests on polymethyl methacrylate and polycarbonate films. By applying Buckingham 𝛱 dimensional analysis to all the impact test results, we demonstrate that the minimum perforation velocity is directly related to the geometric and material properties of each system across a broad range of size and energy scales. Interestingly, we find that the failure stress of the polymer, a critical material property that defines perforation resistance, can be empirically determined based on the deformation of the specific impact test.

19 Sep 2025

Design and Development of Large Format Additive Manufacturing Techniques

Abstract: This report discusses the creation of a large format additive manufacturing (LFAM) printer and initial test printing with the machine. A pellet-extruder head was attached to a computer numerical control (CNC) gantry. The team at the US Army Research and Development Center (ERDC) modified gantry arms to increase build height and designed electronic controls to allow for control of the printhead and the heated print bed. This report also covers print parameter optimization and print settings development.

17 Sep 2025

Vehicle Barrier Application for Soft Asset Protection at US Army Corps of Engineers (USACE) Dam Facilities

Abstract: The US Army Corps of Engineers (USACE) operates recreational areas at more than 400 lakes and river projects in 43 states. The rise of vehicular ramming attacks, in addition to attacks from vehicle-borne improvised explosive devices (VBIEDs), necessitates physical security measures to protect soft assets at these facilities. Therefore, a comprehensive vehicle-control plan, which includes the appropriate placement of effective vehicle barriers, is important for dam owners and operators to maintain safety at their facilities. This guide consolidates requirements, standards, and the design basis for barriers from multiple sources to provide dam owners with a resource to better protect against vehicular threats.

11 Sep 2025

Influence and Mechanisms of Mineral Chemistry and Sizing Effects on Cementitious and Pozzolanic Reactions

Abstract: This study investigated whether materials traditionally considered inert could become reactive with increased fineness. Researchers used multiple techniques to produce materials in a variety of fineness levels. The final products were then analyzed for pozzolanic reactivity in accordance with ASTM 1897 and for their influence on portland cement hydration in accordance with ASTM C1702. Results indicated that pozzolanic reactivity was not produced by successive grinding for either chemistry, at least within the limits of the techniques used. Both chemistries were shown to influence the rate of portland cement hydration when ground finer than cement. This phenomenon is known as the filler effect, and it became more significant with increased fineness.

10 Sep 2025

Geology, Geomorphology, and River Engineering in the Memphis-to-Rosedale Reach, Lower Mississippi River

Abstract: This study examines the geology and geomorphology of the Mississippi River between Memphis, Tennessee, and Rosedale, Mississippi, with a focus on the Tertiary (65 to 2 million years) surface and how the present-day river has impacted this surface. Previous mapping efforts involving the Tertiary surface by the US Army Corps of Engineers are reviewed. Relevant maps are included as plates herein to facilitate wider dissemination. Today’s channel has deepened through time due to river engineering, which includes oxbow cutoffs and hardening of river banks with revetment and training dikes to prevent uncontrolled bank caving and channel migration. The course of the river was fixed in place by 1962. The thalweg of the river intersects the Tertiary surface at Helena, Arkansas, at the Hardin oxbow cutoff, and near the vicinity of Memphis, Tennessee. At these three locations, the Tertiary surface occurs at shallow elevations and in close proximity to where Tertiary sediments outcrop. A deeply buried alluvial valley is present in the Tertiary surface. Erosion of Jackson Group sediments in this valley exposes the underlying Claiborne Group sediments. Jackson and Sunflower oxbow cutoffs occur in the deepest parts of the alluvial fill.

10 Sep 2025

Evaluation of the Plate Load Test for Design of Rigid Airfield Pavements Using Various Plate Sizes

Abstract: This report addresses the state of knowledge of the plate load test and modulus of subgrade reaction (k), industry’s desire to simplify the plate load test, and the effect of the k-value on rigid pavement design. The report traces back the theory behind the k-value over 150 years to evaluate the current state of knowledge. A total of 144 plate load tests were executed on three subgrade materials under varying base course thick-nesses. Plate load testing was designed to evaluate various plate sizes and testing standards (e.g., the military standard CRD-C 655-96 and the ASTM International [commonly called ASTM] standard ASTM D1196-21). By measuring plate load tests on varying base course thicknesses, field-measured effective k-curves were developed. Overall, results show that kASTM was higher than kCRD. Although a smaller plate setup produced similar results, additional variability was introduced when using smaller plates. The results of the field data imply that the current effective k-curves underestimate the global stiffness contribution provided by the base layer. Findings suggest the analytically generated effective k-curves validate the measured k-values in the field.

9 Sep 2025

Using Transfer Learning to Enhance Void Detection and Shear Wave Velocity Model Inversion from Near-Surface Seismic Shot Gathers

Abstract: A Convolutional Neural Network (CNN) has been designed to delineate the shear-wave velocity (Vs) models and detect subsurface void locations. Addressing the processing and interpretation challenges posed on real seismic data, our strategy emphasizes that leveraging the ground truth, which is the void location in this study, enables the CNN to catch the identical features in real waveforms. Initially, a synthetic dataset is employed, imparting foundational knowledge to the CNN regarding the Vs model and void locations. Drawing inspiration from transfer learning, this pre-trained CNN serves as an initial model and is refined using a real dataset focused on void locations. After refining, the CNN shows enhanced reliability to detect the void and extract the Vs model, as evidenced by the improved alignment between forward modeling and real waveforms. Our findings underscore how leveraging the ground truth can actualize the potential of CNN on velocity model extraction.

9 Sep 2025

Damage Parameters and Crack Morphology in High Strength Concrete BBR9 Under Dynamic Uniaxial Compressive Loading: An Experimental Study

Abstract: There has been significant growth in the use of high-strength concrete in structures designed to withstand extreme events. Continuum damage mechanics has been utilized to develop constitutive models that can capture the damage evolution in concrete materials under such conditions. This study is aimed at investigating the damage initiation, progression, and morphology of HSC-Baseline Basic Research Mixture 9 when subjected to dynamic uniaxial compressive loading. A Kolsky compression bar system was implemented to introduce distinct damage states in the HSC-BBR9 specimens. The partially damaged specimens were tested to quantify their residual mechanical properties. Accordingly, stiffness-based and strength-based constitutive damage parameters were adopted to propose an indirect quantification of the damage state based on the deterioration of mechanical properties. The X-ray micro-computed tomography technique was utilized to extract measurements of 3D crack networks that provide a direct quantification of the damage state based on microstructural evidence. The results demonstrated the HSC-BBR9 material can maintain its residual mechanical properties into the post-peak regime. In the initial stages of damage, stiffness and strength deteriorate at a proportional rate; however, as damage accumulates, the rate of stiffness degradation increases. Correlations between constitutive damage parameters and 3D crack measurements were established.

3 Sep 2025

Optimal Transport-Based Full-Waveform Inversion for Shallow Seismic Data

Abstract: Full-waveform inversion is widely used to reconstruct subsurface properties at different geologic scales. For shallow land applications using surface waves, a lack of information on the source wavelet, dispersion, and presence of higher modes increases the nonlinearity of the inverse problem. The inversion can become more challenging with the presence of near-surface complexities associated with scattering, attenuation, and high-contrast variations in the elastic parameters. Compared with the least-squares formulation, GSOT provides a more convex misfit function and reduces dependence on the accuracy of the initial model. Although a few field-data applications have shown the potential and benefits of using GSOT-based FWI with body waves, there are limited real applications of the inversion with a GSOT misfit function for NS characterization. Despite considerable effort with blind benchmark tests in exploration seismology, typically synthetic FWI examples for NS applications are demonstrated through an “inverse crime” approach. Synthetic FWI examples performed compare the performance of LS- and GSOT-based FWI with more realistic scenarios. We demonstrate the GSOT misfit function improves the initial 1D velocity models and guides the updates toward the actual subsurface properties. This enables the recovery of higher-mode Rayleigh waves and reconstruction of the cavity with better precision.