To address the need for expedient repair solutions for paved runways in cold environments, airfield damage repair Rapid Airfield Damage Recovery (RADR) materials were tested at temperatures down to-40 ºF. New materials and methods were developed to fill the identified performance gaps for conventional RADR materials. Simulated crater repairs were performed at-20 and-40 ºF. Folded fiber glass panels and hinges met the published tensile strength, but did not meet the required flexural strength. Fiberglass-reinforced polyester panels retained their 73 ºF tensile and flexural strengths down to-40 ºF. If required, foreign object debris covers can be used at temperatures below freezing, but further experimentation is needed to fully assess matting candidates at temperatures below 0 ºF. Geocell sidewalls and junctions showed an increased maximum force, with a tenfold decrease in the displacement before failure. Rapid setting flowable fill and polyurethane foam, prepared conventionally, were demonstrated as backfill materials at temperatures as low as 0 ºF. As a cap material, Rapid Set ® concrete can be placed using conventional techniques down to 17 ºF. Snow and ice materials were demonstrated as backfill materials below freezing and met the strength requirements for capping applications at temperatures down to-40 ºF. 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.
Small (5.56 mm, 7.62 mm and 9 mm) and medium (12.7 mm) arms rounds were fired at snow-filled 1.5m cubic gabions in a mid-winter condition in Fairbanks, Alaska. The rounds were excavated and penetration by each ammunition type was measured. A distribution and average of penetration depth was determined. All 320 rounds fired were captured within 1.5m after entering the snow barrier. Comparison with published models of ballistics penetration of snow showed mixed results with several matching our data within 10% and all but one within 32%. However, most of these models are simplistic in that they accommodate limited variables and therefore may not be expected to perform well in all settings. We conclude that snow-based ballistics protection structures can be quickly and efficiently erected in suitable environments and with minimal size, can provide reliable protection against small and medium arms fire.
A first-of-its-kind snow runway for wheeled aircraft operation at McMurdo Station, Antarctica, demonstrated that robust structures can be made of snow that push the limit of what is known about snow strength and how to parameterize it. We conducted a series of laboratory tests to determine the links between snow density and snow compressive strength for very highdensity snow structures. We constructed snow samples of varying densities to mimic the snow structures of the constructed runway and measured the resulting snow microstructural and mechanical properties. The goal of this work is to ultimately increase our understanding of the role of density, as an easy-to-measure parameter, in determining snow strength as it relates to snow construction applications (e.g., snow runways, tunnels, and foundations) and how to best quantify the relationships between microstructure, density, and strength of very dense snow structures. Our values for the mechanical properties compared relatively well with the compilation of past historical results. Based on our results, to a first order approximation, snow microstructure data can be used to help improve snow strength predictions. Important future work would focus on improving these snow microstructure-strength relationships to include the effects of meteorological forcing.
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