Abstract
A flexible test pavement, instrumented to measure stresses and strains in three primary axes within the upper 42 cm (16.5 in.) of the subgrade, was constructed and load tested in the Danish road testing machine, as part of the international Pavement Subgrade Performance Study, to improve the mechanistic subgrade failure criterion. The test pavement was constructed in 1995 and load tested between 1995 and 1996. Simulated traffic loads were applied by a dual-tire loading cart within a climate chamber maintained at a temperature of approximately 25°C (77°F). Two dual-tire load levels of 20 kN (4495 lbf) and 40 kN (8990 lbf) were applied for 50,000 load repetitions each. Instruments installed in the test pavement included strain measuring sensors (strain deformation transducers and an ॖ strain-measuring system using induction coils), soil pressure cells, asphalt strain gauges, soil moisture probes, and pore pressure sensors. Routine monitoring of the pavement at regular intervals during the load testing program included measurement of surface profiles with a profilometer and falling weight deflectometer testing. Described here are the test pavement, the pavement materials, the types and positions of instruments installed in the pavement, typical instrument readings, and the surface profile monitoring and structural testing undertaken during the load testing program.
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