4 May 2021

First Generation Automated Assessment of Airfield Damage from LiDAR Point Clouds

Abstract: This research developed an automated software technique for identifying type, size, and location of man-made airfield damage including craters, spalls, and camouflets from a digitized three-dimensional point cloud of the airfield surface. Point clouds were initially generated from Light Detection and Ranging (LiDAR) sensors mounted on elevated lifts to simulate aerial data collection and, later, an actual unmanned aerial system. LiDAR data provided a high-resolution, globally positioned, and dimensionally scaled point cloud exported in a LAS file format that was automatically retrieved and processed using volumetric detection algorithms developed in the MATLAB software environment. Developed MATLAB algorithms used a three-stage filling technique to identify the boundaries of craters first, then spalls, then camouflets, and scaled their sizes based on the greatest pointwise extents. All pavement damages and their locations were saved as shapefiles and uploaded into the GeoExPT processing environment for visualization and quality control. This technique requires no user input between data collection and GeoExPT visualization, allowing for a completely automated software analysis with all filters and data processing hidden from the user.

10 Jun 2020

PUBLICATION NOTICE: Full-Scale Testing of Commercially Available Cementitious Backfill and Surface Capping Materials for Crater Repairs

Abstract: The Air Force Civil Engineer Center (AFCEC) Rapid Airfield Damage Recovery (RADR) program currently utilizes rapid-setting flowable fill (RSFF) and rapid-setting concrete (RSC) for backfilling and capping crater repairs. These materials have been proven successful through many full-scale tests, troop demonstrations, and live flight trafficking. However, only one proprietary product is currently approved for each material. Two candidate capping materials and one backfill material were evaluated by conducting simulated crater repairs and collecting appropriate data. For capping products, both small (8.5 ft x 8.5 ft) and large (15 ft x 15 ft) repairs were conducted and trafficked with simulated F-15E aircraft traffic. For the backfill material, three small repairs were backfilled and the California Bearing Ratio (CBR) was estimated at cure times of 0.5, 2, and 24 hr. Overall, repairs capped with Western Materials Fastrac 246 failed after only 2,000 passes, so the material is not currently recommended for approval. Repairs capped with Buzzi Unicem Ulti-Pave3® were able to sustain 3,500 passes before trafficking was ceased, so this material is recommended for approval as a crater repair capping material. CTS rapid-setting flowable fill backfill exhibited lower than expected CBR values and did not allow timely percolation of mix water, so it is not currently recommended for approval at this time.

29 Apr 2020

PUBLICATION NOTICE: Laboratory Characterization of Rapid-Setting Flowable Fill

Abstract: Utility Fill One-Step 750® is a rapid-setting flowable fill product that has previously been validated in numerous full-scale demonstrations as an expedient backfill solution for Rapid Airfield Damage Recovery. Although the field performance of Utility Fill One-Step 750® has been extensively documented, a full laboratory characterization has not been conducted. This report analyzes and documents results from several laboratory tests conducted at two water to-product ratios. The tests conducted are based on the suite of tests that make up the triservice spall repair certification program used for rapid-setting concrete products. Tests include strength and set time-related properties, typical parameter control tests for concrete, and tests to determine the mineralogy and chemical makeup of the material. Long-term expansion and contraction properties were also tested. The data presented herein are intended to provide an overall assessment of Utility Fill One-Step 750® and to provide reasonable estimates of various design parameters. The results can be used as a basis for the future development of a formal laboratory certification protocol to down-select other rapid-setting flowable fill products for further evaluation.

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.

28 Apr 2020

PUBLICATION NOTIFICATION: Evaluation of Rapid-Setting Cementitious Materials and Testing Protocol for Airfield Spall Repair

Abstract: The rapid-setting cementitious material certification program is part of a research effort to assist the U.S. Air Force Civil Engineering Center in the execution of independent testing on select commercially available proprietary products to repair partial-depth spalls in airfield concrete pavements. The purpose of this research was to determine whether the existing requirements for evaluating rapid-repair products for spall repairs were sufficient or further refinement and modifications were needed. This protocol is intended to aid airfield managers and repair teams in the selection of optimal spall repair materials by maintaining a database of approved tested products. This report presents the test methods and results of 26 cementitious rapid-setting repair products tested at the U.S. Army Engineer Research and Development Center in Vicksburg, MS, during 2013 to 2017. An evaluation of these test methods and results, along with the historic database of products tested, led to the development of an updated testing protocol for assessing a material’s suitability for airfield spall repairs. Based on the revised criteria, 10 products were identified as most compatible for partial-depth airfield pavement concrete spall repairs.

7 Apr 2020

PUBLICATION NOTICE: Development of Magnesium Phosphate Cement (MPC) Concrete Mixture Proportioning for Airfield Pavements: Laboratory and Field Validation MPC Test Report

 Link: http://dx.doi.org/10.21079/11681/35475Report Number: ERDC/GSL TR-20-4Title: Development of Magnesium Phosphate Cement (MPC) Concrete Mixture Proportioning for Airfield Pavements:Laboratory and Field Validation MPC Test ReportBy Monica A. Ramsey, Dylan A. Scott, Charles A. Weiss Jr., and Jeb S. TingleApproved for Public Release; Distribution