Assessment of laboratory and field compaction of dense graded aggregate bases (dgab)

Abstract

Dense Graded Aggregate Base (DGAB) construction is a major contributing component in flexible pavement construction in terms of pavement structural capacity and the project cost. However, the production processes related to DGAB construction impose more significant financial, environmental, and social concerns, which stresses the effective compaction in DGAB construction. DGAB compaction process is controlled by three governing factors: moisture content (MC), compaction effort, and layer thickness, where compaction effort can be minimized when field compaction takes place at MC levels closer to the estimated Optimum Moisture Content (OMC). Hence, the relationship among maximum dry density (MDD), OMC, and compaction effort should be well established for a given layer thickness in such a laboratory method that best interprets the field practice. Information on the current industry compaction practices was gathered by conducting a questionnaire survey. Simultaneously, laboratory and field tests were carried out to compare the compaction behavior of DGAB at different MCs and energy levels. Moisture density plots of different laboratory and field compaction tests were compared to determine the most suitable laboratory compaction method to simulate the field compaction of DGAB. The study revealed that the vibratory hammer test resulted in the highestMDDand the lowestOMC,wheremoisture-density curves of the field compaction tests were approaching the vibratory hammer test curve with the increase of compaction effort, emphasizing that the vibratory hammer test best simulates field compaction, when compared to other laboratory impact compaction tests.