Accelerated Pavement Testing

The Accelerated Loading Facility (ALF) is used to simulate heavy vehicle trafficking on pavement structures under controlled conditions. The ALF allows pavements to be tested and for their performance to be evaluated in a very short time compared with test sites under normal traffic.

The Accelerated Loading Facility (ALF) is used to simulate heavy vehicle trafficking on pavement structures under controlled conditions.The ALF uses a directly driven load trolley to apply rolling wheel loads in a single direction to pavement strips, at a nominal speed, using a constant mass.The load is applied to the pavement through a load assembly trolley which consists of a standard heavy vehicle trailer hub, supporting a load trolley chassis and weight bed.

This trolley chassis tracks linearly, guided by rails mounted on the ALF main frame, and is driven directly, by a single 22kW motor rotating the wheel hub. The wheel is lifted off the pavement at the end of each cycle and supported by the main frame on its return.

By loading in a single direction only, the ALF is able to simulate real-world trafficking conditions and conserve the majority of its kinetic energy, via the rising curvature of the rails at each end. The input energy required is only to overcome rolling resistance, grade and cross fall and to lift the load wheels once per cycle.
The ALF control system provides a programmable automatic transfer movement to simulate normal traffic wander across a typical wheel path width.'
The original ALF was developed in Australia by the Roads and Traffic Authority of New South Wales. A number of long term pavement performance (LTPP) studies have verified ALF results against pavement performance under real traffic and environmental conditions.

The Australian ALF has been used for more than 250 experiments over 25 years, applying over 32 million load passes and simulating well over 300 million Equivalent Standard Axle loads.The Accelerated Loading Facility (ALF) is used to simulate heavy vehicle trafficking on pavement structures under controlled conditions.