Evaluation of an accelerated pavement testing facility and development of its load equivalence factors

An accelerated pavement testing facility (APTF) was used to simulate the effect of traffic on pavement performance. An enhanced procedure was developed in this study to calculate the load equivalence factors (LEF) for APTF. Results indicated that this procedure is feasible to evaluate the effect of heavy axle loadings on pavement performance under an accelerated rate. The pavement performance after APTF followed the trend observed on full-scale test roads. Based on the present serviceability index loss of the APTF data, it was found that an eighth-power law existed for the APTF in contrast to the fourth-power law in full-scale test roads. This implied that the LEF for APTF single-axle loads of the same configuration was equal to the ratio of the axle weights raised to the eighth power. This finding explained why pavements tested by the APTF failed much faster than regulated loading. Critical loads, however, appeared to be present for pavements tested by the APTF. Pavements tested with loads greater than the critical load might fail predominantly by traffic loading.