Roller evaluations are rather phenomenological -- that is, one must rely somewhat on observations. Density measurements following each excursion of the compactor may not relate directly to the work done in compressing the layer. When no increase in density is realized, no work is accomplished. Work is defined here in the classical sense. Energy expended without producing an increase in density is wasted. Thereafter, the only way additional classical work can be done on the layer is to reduce density.

The number of excursions necessary to achieve an acceptable or comparable density generally reflects efficiency of the compactor. Much may depend on weight, speed, size of wheels, and modes of operation. When viscous traction (time-dependent resistance to densification) is involved, the dwell time (or dwell time x number of excursions) becomes very significant. Dwell time is proportional to speed; but, in a vibrating mode, bearing stress of the roller wheel varies.

Report Date


Report Number

No. 328

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