Rapid Measurement of Ice Density by Compact Nuclear and Membrane Methods

Rapid and accurate field ice density measurement is required to determine the load bearing capacity of ice, the load ice imposes on existing structures, and the electromagnetic signature of ice. Current ice density determinations use mass volume techniques and submersion techniques on ice core samples. A Phase I effort, to determine the feasibility of accurately measuring ice density with a nuclear and a membrane method, is proposed. The nuclear method is currently used throughout the United States to measure soil density and moisture content at earthwork construction sites. The nuclear method has been demonstrated for ice density (and salinity) measurement on a limited basis in the former Soviet Union. The membrane method improves the accuracy of determining volumes (a major source of error) by the proven mass-volume technique. Phase I will apply these technologies to benchtop ice density measurement. Benchmark ice specimens will be used to evaluate the accuracy and repeatability of the two techniques. A determination will be made as to which technology will be advanced in a Phase II study. Both can be configured into a rugged portable field unit for measuring core samples. The nuclear device can also be configured as an in-situ measuring device. BENEFITS: Successful development of a small, portable, and easy to use method for rapid measurement of ice density will provide a useful tool for determining the load bearing capacity of ice, the ice imposed loads on structures, and the electromagnetic properties of ice. This information is of great interest to military agencies and geophysical research, as well as municipalities and industries that have to deal with frozen bodies of water and ice loading.