68th Canadian Geotechnical Conference and 7th Canadian Permafrost Conference

SETTLEMENT OF A BRIDGE FOOTING SUPPORTED ON RECLAIMED ASPHALT PAVEMENT BACKFILL

Session: Transportation and Linear Infrastructure II / Transports et infrastructures linéaires II

Brian Hall, Tetra Tech EBA (Canada)
Brian Gummeson, Senior Technologist (Canada)

This paper describes the greater-than-expected settlement of a perched bridge abutment footing supported on a mechanically stabilized earth (MSE) wall. A possible reason advanced for the greater than expected settlement was the presence of reclaimed asphalt pavement (RAP) material in the MSE backfill. This possibility was assessed by reviewing the published literature, and conducting a limited laboratory test program comparing the settlement potential of RAP to conventional MSE backfill. The published literature shows that RAP settlement depends on asphalt cement binder content and performance grade, asphalt age, and aggregate characteristics, and generally cautions against the use of RAP because of concerns regarding creep deformations. The laboratory tests showed settlement increased as both asphalt cement and moisture content increased, and led to the conclusion that the observed settlement may have resulted from the use of RAP backfill.