Creep of compacted recycled asphalt pavement

Recycled asphalt pavement (RAP) can be beneficially used as fill in the construction of earth structures such as embankments and retaining structures. Experiments were conducted to evaluate the creep response of compacted RAP under sustained deviatoric stresses. Constant stress, consolidated- drained triaxial tests were performed on 100 mm diameter, compacted RAP specimens at multiple confining stresses and deviator stress levels. The test data displayed classic creep behavior, with clearly identifiable primary and secondary creep observed in all specimens. Tertiary creep and creep rupture were observed in specimens tested at larger deviator stress levels. The creep response of RAP was significant at confining pressures less than about 272 kPa, while the creep response was less severe at larger confining pressures. Upper yield stress levels, representing the deviator stress levels below which creep rupture does not occur, were identified and shown to be confining stress dependent. In general, the creep potential of RAP is significant and should be considered in design. The developed creep models can be used to predict the time- dependent deformation of earth structures utilizing RAP backfill.