Effect of Compaction Method on Mechanical Behavior of Graded Aggregate Base Materials

Abstract

Previous studies indicated that the properties of aggregates and their compaction process are the most important factors in the design of granular highway base layers. It was argued that the conventional compaction method (impact compaction) did not fully reflect the real field performance of the granular materials. In the current study, the effect of aggregate properties and two different compaction methodologies on the mechanical behavior of granular highway base materials is investigated. Four different graded aggregate base materials were used. A series of sieve analysis, compaction tests, California bearing ratio (CBR) tests, and resilient modulus tests were conducted to determine the effects of two different compaction methods on the mechanical behavior of graded aggregate base materials. The results indicated that impact compaction altered the gradation of base materials by breaking the aggregates into smaller particles, the GAB fines content increased and yielded an increase in optimum moisture contents (OMC). In addition, CBR values of the specimens prepared with vibratory compaction method were higher than the CBR values of the specimens prepared with Impact compaction method. On the other hand, the specimens prepared with the impact compaction method yielded higher SMr values than the specimens prepared with the vibratory compaction method, except Bladensburg GAB.