Bearing Capacity of a Flexible Pavement during the Construction Phase

A flexible pavement section from an important motorway in Lisbon was instrumented during the construction phase, in 1996 and 1997, with deformation gauges being placed at different levels: longitudinal and transversal horizontal gauges at the bottom of the bituminous layers, and vertical gauges on the top of the unbound granular materials and subgrade soil. The structure of this pavement is composed of: binder and base layers in bituminous concrete; sub-base in unbound granular materials; subgrade soil. The temperature of the bituminous layers was measured by thermoelectric couples. To study the bearing capacity of the structure, wheel load tests were carried out after the construction of each layer of the pavement. Falling Weight Deflectometer (FWD) tests were also carried out for different loads applied to the final pavement structure. During these load tests, strains and temperature measurements were made. The main conclusions obtained from load tests results indicate that the bearing capacity of the instrumented pavement differs according to the type of load applied (quasi-static or dynamic) and behaviour of pavement materials is non-linear. The influence of bituminous macadam temperature and binder course thickness was also analyzed.