The performance and sustainability of vehicle dust courses for military testing

Dust has long been recognized as an important parameter for testing military vehicles and equipment due to the potential for adversely affecting performance and durability. Vehicle dust test courses were originally established in areas of heavy underlying fine particulate layers (silt and clay) and used for cyclic tests. These soils, known as desert pavements, are geomorphically old and slowly develop through the trapping of atmospheric dust over tens of thousands of years. As such, these soils are both a sink and source for eolian material. However, this dust is a finite resource for military testing at the Yuma Proving Ground (YPG), the Army’s primary environmental hot weather test center. There is concern that the continuous utilization of YPG dust test courses over the past half century has eroded through the overlying dust-rich soil to the extent that the true natural environmental conditions are no longer adequately represented. The objectives of this study were (1) to characterize current dust courses at YPG in order to (2) gain a better understanding of the current state of dust availability and (3) assess the overall sustainability of high dust-potential soils needed for proper military testing. Soil samples collected from dust test courses and adjacent undisturbed soils, as well as dust collected on tactical test vehicles, were analyzed for mineralogy, geochemistry, and physical properties. Results indicate adjacent undisturbed soils exhibit a higher dust potential (higher silt and clay) and elevated reactive salts and carbonates indicating a significant loss of fines from the dust test courses. Routine vehicle traffic and surface preparation has eroded and mixed the dust layer with the underlying sand and gravel-rich horizons, thus depleting the dust test courses of their dust producing potential. Desert pavements are stable geomorphic landforms but the soils have finite dust content when disturbed and therefore are unsustainable for long-term repeated dust testing. Disturbance of these soils may potentially affect ecologically sensitive areas. As such, more geomorphically active areas such as floodplains may provide greater sustainability for long-term testing.