Compaction Characteristics of Earth-Rock Mixtures. Report 2. Blended Material,
ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MISS
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Due to limitations of equipment size, compaction characteristics of earth-rock materials are usually determined by laboratory tests on samples contained in small molds and having maximum particle diameters less than those of the full-scale material. Corps of Engineers laboratories perform such tests on samples from which oversized particles have been scalped and replaced, assuming that test results are comparable to those that would have been obtained on full-scale samples. The objectives of this investigation were to determine the validity of the scalping and replacement procedure to evaluate two commonly used theoretical methods of computing dry unit weights of full-scale specimens using results from tests performed on minus No. 4 fractions of the total specimen. The tests indicate that the scalping and replacement procedure results in significantly lower maximum dry unit weight and higher optimum water contents than those obtained for full-scale specimens. The use of the theoretical methods provided better approximations of experimental results on full-scale specimens having gravel contents up to 60 percent than the relationships developed using the scalping and replacement procedure. In order to fully define effects due to the scalping and replacement procedure, further testing is needed to determine effects of variations in equipment sizes.
- Geology, Geochemistry and Mineralogy
- Test Facilities, Equipment and Methods