The performance of ctb pavements under accelerated loading - the beerburrum (qld) alf trial

Over 2.2 Million loading passes have been applied to 19 test sections during the beerburrum (qld) alf trial. The series of experiments was carried out on ctb pavements built to similar standards but different designs to investigate their response to and behaviour under heavy traffic loading. Sections 200 and 330 mm thick were trafficked to establish the failure mechanisms and to investigate the performance of these pavements under different load magnitudes. The effects of early trafficking were investigated by applying a limited number of standard axle loads to four test sections within a short time after construction. The major experiments were also complemented by testing similar pavements with and without a bond breaker bitumen heavy cure coat and a pavement section built in one lift, instead of the usual two. The typical failure mode was the debonding of layers followed by erosion of the interfaces. The damage in the pavement structures progressed from the upper layers towards the lower ones. It is recommended that this failure mode be taken into consideration in both the design and evaluation procedures (a).