Downloads & Free Reading Options - Results

The physical characteristics of snow and those processes of metamorphism which contribute to its strength are important considerations in planning the construction of compacted snow runways. Two distinct temperature- dependent processes affect the physical properties of snow: sintering and strength increase with decreasing temperature. The rate of strength increase and the ultimate strength of snow may be greatly increased by mechanical agitation or depth processing followed immediately by surface compaction. Leveling to produce a smooth surface for aircraft is also necessary. Various combinations of processing and compaction are required depending on the size of aircraft to be operated on the runway. After construction is completed, the natural process of sintering or strengthening must be allowed to proceed for some time before aircraft operations can be initiated. The mechanical properties of processed snow have been correlated with its wheel-load supporting capacity. The correlation shows the effect of such parameters as wheel load, tire contact pressure, and repetitive wheel coverages on the required hardness or strength of a compacted snow layer. Strength profiles which can be expected from certain snow processing and compaction procedures are shown and compared with required strength profiles for various types of wheeled vehicles and aircraft. The purpose of this study was to combine the knowledge gained from fundamental research in the processes of sintering with methods and procedures developed by engineers for using snow as a construction material.