An important task in the rapid airfield damage recovery (RADR) crater repair process is screeding the capping material, which may be either hot mix asphalt or rapid-setting concrete. The repaired surface must meet roughness quality check (RQC) requirements of ±0.75 in. to prevent fighter aircraft damage. Currently, the screeds recommended to meet RQC criteria for concrete repairs are cumbersome, slow, and require three or more personnel. Additionally, no screed has been identified to enable proper asphalt repairs. This project's objective was to evaluate prototype screeds (two asphalt, two concrete) and propose a single integrated screed for screeding either material to assist the RADR program in its efforts to develop lighter, leaner equipment. The new screed must also reduce manpower requirements, be less cumbersome to operate, and be able to perform small and large crater repairs. All four prototype screeds evaluated within the scope of this study reduced manpower and created a satisfactory surface finish when properly employed. Key differences affecting results were screed board shape and the ability to control the grade of the screed. Ultimately, the telehandlerpowered Autoskreed was selected as the most promising system because both asphalt and concrete screeding activities could be integrated into a single device. Additional attachments were designed and tested, and a final integrated screed design is presented in this report that satisfies the project's objectives. DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents.

Airfield matting systems are used for the expedient construction of temporary airfields and the expansion of existing airfields to provide temporary airfield operating surfaces for military aircraft. The primary airfield matting system used by the U.S. Military is the AM2 airfield matting system. Although the AM2 matting system has proved to be successful for supporting modern aircraft, it is difficult to transport by air because of its size and weight. The AMX program was initiated by the U.S. Air Force to identify and evaluate new, lightweight airfield mat designs optimized for C-17 transport. Three commercially available matting systems of varying materials and designs were evaluated through the construction of a full-scale test section to determine their effectiveness at sustaining modern fighter aircraft loads and at reducing the accumulation of subgrade deformation. The matting systems were tested on a subgrade with a California bearing ratio (CBR) of 6 and subjected to simulated F-15E aircraft traffic while monitoring mat breakage and deformation. The systems were compared against baseline requirements established for the AMX program, which were established to match the performance of AM2 while providing a reduced logistical footprint. The systems tested in the experiments described in this report are not suitable alternatives, but improvements to mat component designs were recommended that could increase performance. DISCLAIMER:The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents.

The evaluation of the interaction between airfield matting and soil under aircraft loading has been part of ongoing investigations under the AMX and Remote Piloted Aircraft (RPA) lightweight mat programs. Full-scale evaluations on controlled subgrades using simulated aircraft loads have successfully provided a realistic performance measure of airfield mats in an operational environment. To better understand airfield mat behavior, a medium-scale bending experiment was performed to determine structural properties that can be related to field performance. This report presents data from experiments performed on new, lightweight matting systems investigated under the AMX and RPA lightweight mat programs using the medium-scale simply supported bending test. Full-scale traffic testing has previously been completed, but the structural and mechanical properties of the lightweight airfield mat designs have not been determined. A finite element implementation of the Mindlin plate theory was used to backcalculate mat modulus and flexural stiffness. Results showed reasonable relationships with field performance.

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The Modified Light-Duty AM2 matting was designed specifically for lightweight, remote-piloted aircraft (RPA) applications. An in-depth study was conducted previously by the U.S. Army Engineer Research and Development Center (ERDC) to characterize and model the mechanical performance of friction stir welding for use in fabrication of the lightweight RPA matting in conjunction with a full-scale test on the Modified Light-Duty AM2 matting system. The study validated the matting's performance when subjected to simulated RPA and support vehicle traffic over a subgrade with a California Bearing Ratio (CBR) of 6. To understand the full potential of the Modified Light-Duty AM2, a fullscale evaluation was performed with contingency C-17 and standard (below maximum) F-15E aircraft loads over a subgrade with a CBR of 6. The test results revealed that the connection between the mat core and the end connector is not strong enough to support loads heavier than RPA traffic. The overlap/underlap end connectors effectively sheared off from the mat core for both test vehicles. Even so, the mat cores showed minimal structural damage from the applied traffic. DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents.