ABSTRACT
ABSTRACT: The Illinois Department of Transportation frequently utilizes dense graded aggregates to provide a stable platform for pavement construction. The performance of three dense graded aggregates having different physical characteristics, construction methods, and thickness was evaluated under controlled loading conditions in a full scale test loop. Prior to paving, test locations were subjected to up to 270 passes by a loaded tandem axle truck. Aggregate rutting at each test location was measured at regular intervals during loading. The results identified three primary factors affecting performance: 1) aggregate angularity, fines content, and fines plasticity; 2) aggregate layer moisture content and compaction; and 3) loading. The test loop results also indicated aggregate properties, rather than underlying soil stability and aggregate thickness, control performance when the soil subgrade has a CBR of approximately 5 or greater. The results show pavement construction platform thickness can be optimized for performance and economy by considering aggregate properties and construction methodology. The results also indicate some aggregates have properties making them inappropriate for use as a pavement construction platform.
