The Federal Highway Administration pavement testing facility - first year operations

This paper discusses the operation and preliminary test results of the US Accelerated Loading Facility (ALF). An ALF device, similar to the Australian device, was fabricated and subsequently placed in operation at the Turner-Fairbank Highway Research Center in 1986. Two 60 m long bituminous concrete test pavements were constructed by the Federal Highway Administration to serve as the outdoor pavement testing facility. The ALF device is used to load the pavements with dual wheel loads which range from 4.3 T to 8.6 T. Pavement performance data is measured with an automated data collection system. Field data elements include transverse and longitudinal profile, surface deflections, pavement temperature, and subgrade moisture content. Included in the data are pavement strains which are measured by in situ strain gauges at the bottom of the asphaltic concrete layer. Other measurements include manual crack surveys and falling weight deflectometer measurements. Preliminary test results from the first two test section experiments are presented. This includes pavement performance in terms of serviceability and rutting. Information is also presented about a tire pressure and load study which was done as part of a special test sequence (a).