12 May 2021

Methodology for Remote Assessment of Pavement Distresses from Point Cloud Analysis

Abstract: The ability to remotely assess road and airfield pavement condition is critical to dynamic basing, contingency deployment, convoy entry and sustainment, and post-attack reconnaissance. Current Army processes to evaluate surface condition are time-consuming and require Soldier presence. Recent developments in the area of photogrammetry and light detection and ranging (LiDAR) enable rapid generation of three-dimensional point cloud models of the pavement surface. Point clouds were generated from data collected on a series of asphalt, concrete, and unsurfaced pavements using ground- and aerial-based sensors. ERDC-developed algorithms automatically discretize the pavement surface into cross- and grid-based sections to identify physical surface distresses such as depressions, ruts, and cracks. Depressions can be sized from the point-to-point distances bounding each depression, and surface roughness is determined based on the point heights along a given cross section. Noted distresses are exported to a distress map file containing only the distress points and their locations for later visualization and quality control along with classification and quantification. Further research and automation into point cloud analysis is ongoing with the goal of enabling Soldiers with limited training the capability to rapidly assess pavement surface condition from a remote platform.

4 May 2021

Joint Rapid Airfield Construction (JRAC) Program 2004 Demonstration Project--Fort Bragg, North Carolina

Abstract: This report describes the demonstration of technologies and procedures developed during April 2002 and May 2004 under the Joint Rapid Airfield Construction (JRAC) Program. The demonstration took place at Sicily Landing Zone (LZ) at Fort Bragg, NC, in July of 2004. The objective of the exercise was to demonstrate the procedures and technologies developed under the JRAC Program by rapidly building two parking aprons capable of supporting C-130 transport aircraft taxiing and parking operations. The exercise was conducted under continuous 24-hr operations to simulate a real-world rapid construction environment. Apron 1 (north apron) was constructed using two technologies, one-half being ACE™ Matting and the other half being a cement-polymer stabilized soil surface. Apron 2 (south apron) was constructed solely of a fiber-cement-stabilized soil system. Both aprons were treated with a polymer emulsion surface application to form a sealed surface against abrasion and water infiltration. The entire construction of both aprons required 76 hr, with Apron 1 finished in 48 hr. The construction of Apron 1 was validated by operation of a C-130 aircraft approximately 31 hr after completion with success and high praises from the aircraft flight crew on the stability and surface of the apron, as well as its dust-abating characteristics.

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.