The Callington ALF trial

Cost effective rehabilitation of road pavements is becoming of prime interest to Road Authorities. With increasing traffic loadings and ageing pavements, an increasing portion of road budgets is being directed towards pavement maintenance, repair and strengthening. A series of full scale pavement tests were recently conducted on a distressed section of the South East Highway near Adelaide with the aim of determining the relative performance of alternative forms of asphaltic rehabilitation. The Department of Road Transport, in conjunction with the Australian Road Research Board, used the Accelerated Loading Facility to test a variety of thin overlay treatments and various thicknesses of asphalt reinstatement. A total of 17 loading experiments were conducted. The relative performance of the treatments was measured in terms of their resistance to surface deformation and crack propagation. Preliminary analysis has provided a ranking of deformation resistance of all asphalt materials used with some modified binders displaying significant advantages over conventional C170 bitumen. Comparative overlay experiments clearly demonstrated a significant extension in treatment life through use of a modified binder in the asphalt overlay (A).