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.

29 May 2024

Finite Element, Petrographic, and Mechanical Analyses of Field-Cored Concrete Fairlead Beam Anchor Rods from Luke Air Force Base

Abstract: The fairlead beam is used to accomplish installation of the Barrier Arresting Kit 12 energy absorber for setback aircraft arresting system (AAS) installations at permanent operating facilities. Typical fairlead beams are affixed to a Portland cement concrete (PCC) foundation pad by a series of anchor assemblies made up of steel anchor rods set in grout inside galvanized pipe sleeves. US Air Force Civil Engineering Center (AFCEC) subject matter experts have identified a pattern of premature failures in these steel anchor assemblies when they are nondestructively inspected during AAS overhauls. The US Army Engineer Research and Development Center was tasked by AFCEC to investigate potential reasons for these premature failures. This report outlines methods and results of a finite element analysis of the anchorage, a visual and petrographic analysis of field-cored PCC anchor rods from Luke Air Force Base, and a mechanical analysis of specimens taken from the anchor rods within the PCC cores. Multiple modes of PCC distress were observed, and corrosion was evident in and around the anchor assemblies. Mechanical testing of specimens from the anchor rods indicated that an inferior grade of steel was used to fabricate these particular assemblies. Finally, observed deviations from design intention are discussed.

17 May 2024

A Dynamic Aircraft Response Model for Determining Roughness Limits

Abstract: Runway roughness poses significant risks to aircraft and aircraft personnel. Roughness irregularities can be found in both civilian and military airfields, from rutting to bomb-damaged repairs. Various methods exist for determining roughness criteria, such as discrete surface deviation evaluation and dynamic response models. Although validated dynamic response models such as TAXI-G were used extensively in the HAVE BOUNCE program from the 1970s up to the late 1990s, modern military aircraft have not undergone the same formal analysis. This paper presents the mathematical formulation and validation of the WESTAX dynamic response model. The computer program is capable of simulating the responses of different critical aircraft components while trafficking over idealized runway profiles. The validation results showed that the numerical model was capable of closely matching field data over single- and double bump events. The findings suggest that the WESTAX dynamic response model is a capable candidate for establishing aircraft roughness limits.

31 Jan 2024

Verification of Current Los Angeles (LA) Abrasion Test Criterion for Aggregate Degradation in Airfield Asphalt Pavements

Abstract: Low-quality mineral aggregates can potentially lead to production, construction, and long-term performance-related problems in asphalt concrete pavements. Therefore, effective qualification criteria for mineral aggregates are paramount. This study was performed to investigate the effectiveness of the Los Angeles abrasion (LAA) test to assess the abrasion resistance of coarse aggregates commonly used in airfield asphalt paving. The LAA test acceptance criteria currently specified by state departments of transportation were examined and compared to the current Department of Defense criterion. Additionally, recent experiences during a forensic evaluation to identify potential sources of excessive presence of foreign object debris on an airfield runway are also briefly discussed in this report. The LAA test and associated acceptance criterion in Unified Facilities Guide Specification (UFGS) 32 12 15.13 were evaluated by testing 24 aggregate sources from various US locations. Also, the Micro-Deval abrasion test was performed as a surrogate abrasion resistance test. Sufficient evidence was not found to suggest adjustments to current LAA test criterion or to recommend the use of an alternative abrasion test. The current UFGS specifications should be improved to provide a more thorough aggregate testing protocol and detailed guidelines regarding aggregate sampling and testing frequency during design and construction of asphalt pavements.

15 Sep 2022

Evaluation of a Prototype Integrated Pavement Screed for Screeding Asphalt or Concrete Crater Repairs

Abstract: Finishing, or screeding, the hot mix asphalt or rapid-setting concrete surface of a crater repair is important for rapid airfield damage recovery (RADR) since it determines the aircraft ride surface quality. The objective of RADR repairs is to expediently produce a flush repair, defined as ±0.75 in. of the surrounding pavement surface, with minimal logistical and personnel burden. Multiple screeds were previously evaluated; the most recent project proposed a prototype design of a telehandler-operated integrated screed for both small and large repairs using asphalt or concrete. This project’s objective was to finalize the prototype design and fabricate and test the prototype RADR screed. The prototype RADR screed was successful for small repairs (8.5×8.5 ft). Large repairs (30×30 ft) were generally successful with modest repair quality criteria (RQC) issues being the only notable deficiencies. Large concrete repair RQC issues were attributed to plastic formwork movement, and large asphalt repair RQC issues were attributed to compaction issues or improper roll-down factors. Methods to mitigate these factors were investigated but should be further evaluated. Overall, the RADR screed was successful from technical perspectives but, functionally, is 600-800 lb overweight. Weight reduction should be considered before entering production.

22 Apr 2021

Rapid Airfield Damage Recovery Next Generation Backfill Technologies Comparison Experiment : Technology Comparison Experiment

Abstract: The Rapid Airfield Damage Recovery (RADR) Next Generation Backfill Technology Comparison Experiment was conducted in July 2017 at the East Campus of the U.S. Army Engineer Research and Development Center (ERDC), located in Vicksburg, MS. The experiment evaluated three different crater backfill technologies to compare their performance and develop a technology trade-off analysis. The RADR next generation backfill technologies were compared to the current RADR standard backfill method of flowable fill. Results from this experiment provided useful information on technology rankings and trade-offs. This effort resulted in successful crater backfill solutions that were recommended for further end user evaluation.

1 Oct 2020

Evaluation of Solid-Polymer-Modified Asphalt Mixtures Phase 1: Construction and Performance Testing of Field Pavement Sections

ABSTRACT:  The durability of flexible pavements in cold regions is a challenge due to the impact of environmental conditions and seasonal variations. Other studies have investigated several modifiers as potential solutions to ad-dress cold climate durability of asphalt mixtures. Among these modifiers, polymer modification has shown promise. This study investigated the addition of solid polymer to asphalt mixtures to improve the performance and structural capacity of the material. Four test sections were constructed with different solid-polymer dosage rates: unmodified control, 2.5% polymer, 5% polymer, and 7.5% polymer by weight of binder. Falling weight deflectometer (FWD) testing was con-ducted at each test section to evaluate the structural capacity and to identify the performance benefits of the solid-polymer-modified mixtures. This study conducted a comprehensive analysis, including maximum pavement deflection, deflection bowl parameters, backcalculation analysis, structural number, and impulse stiffness modulus. The field investigation results revealed structural benefits in test sections with the solid-polymer-modified mixture (7%–30% increase in stiffness, depending on the dosage rate). Results suggest that solid-polymer modification could be useful in improving the stiffness of asphalt pavements without compromising durability. Therefore, further investigations should evaluate the durability of the solid-polymer-modified asphalt pavements under different environmental conditions.

28 Apr 2020

PUBLICATION NOTICE: Feasibility Investigation of Inductive Heating of Asphalt Repair Materials

Abstract: Airfield pavement repairs conducted as part of rapid airfield damage recovery (RADR) activities must utilize suitable materials to reduce the need for subsequent repairs in order to maintain an operable pavement surface. For asphalt concrete pavements, hot mix asphalt (HMA) is typically used, but this requires a fairly large operation and is less practical for small repairs (e.g., small munitions damage, potholes). Instead, cold mix asphalt (CMA) is typically used for small repairs; however, its performance under aircraft loads is generally unacceptable.  The objective of this project was to investigate the feasibility of rapidly heating small-repair quantities (e.g., 5 gal buckets) of asphalt mix to hot mix temperatures in a matter of minutes. This objective was met using 15% steel aggregate by volume to produce an inductive HMA (iHMA) that could be heated from ambient to 320°F in approximately 5 min. This technology was demonstrated at full scale with a prototype field induction heater; iHMA patch repairs were subjected to simulated F-15E traffic and exhibited comparable rutting resistance to conventional HMA, which was considerably improved relative to CMA. Overall, iHMA was found to be a feasible repair material and should be considered for additional refinement and eventual implementation.