Characterization of pavement subgrade soil using gyratory compaction

Abstract

A parameter used to carry out the quality control of unbound compacted soil materials is the maximum dry unit weight obtained from a standard or modified Proctor test. However, these tests are far from simulating the field compaction mechanism produced by roller equipment. The gyratory compactor has been put forward as a new laboratory equipment to determine the compaction curves in the Highway Construction and Pavements Laboratory accommodated in the Polytechnic School of Democritus University in Xanthi Greece. Results of Proctor and modified compaction curves as well as those obtained from the gyratory compactor are presented in the current paper. The controlled variables in the gyratory compactor were the vertical pressure, the gyration angle, and of course the number of gyrations. The compaction curves are more or less similar disregarding the rate of gyration and gyration angle. The dynamic compaction yielded better results compared to those obtained by the gyratory compactor. The difference between the two compaction modes was greater at low moistures. Three different moistures were used. In any case, the dynamic method led to higher dry density values. California Bearing Ratio specimens prepared with dynamic or gyratory compaction have lower values with an increase in moisture contents and were generally greater in the case of dynamic compaction.