The Nisku Test Road: Direct Measurement of the Impact of Heavy Loads on Thin Membrane Pavements

This paper describes the design and construction of the Nisku Test Road in Alberta which is designed to monitor the pavement response under heavy oilfield cranes (with hydraulic suspensions and super single tires) on thin membrane asphalt pavements. Three 50m test road sections (thin asphalt wearing course, bituminous surface treatment and granular surface) were built and instrumented for strain at the bottom of the asphalt layer, surface deflection, and subgrade pressures. Temperature and moisture profiles are also measured. Field testing involved controlled speed experiments of standard axle configurations and heavy (12,000kg) axle vehicles with and without hydraulic suspensions. The results presented are from the first two cycles of testing at the site where vehicles upto 95,500 kg were evaluated in an attempt to understand the impact of these large vehicles on thin membrane pavements. The tests are part of a long term study to evaluate pavement performance and to develop load equivalency factors.