Strength and Creep Characteristics of Reclaimed Asphalt Pavement–Sand Blend Backfill in Mechanically Stabilized Earth Walls

Abstract

Using reclaimed asphalt pavement (RAP) as a backfill for mechanically stabilized earth (MSE) walls provides both environmental and economic benefits by allowing in situ recycling for road widening projects. RAP, a well-drained granular material, has lower reinforcing strip pullout strength than A-3 sand and creeps under constant load. The objective of this research was to determine whether blending RAP with A-3 sand would improve RAP's performance in MSE applications. Laboratory specimens of 100% RAP, 100% A-3 sand, and 50% RAP–50% sand blends were compacted by the modified Proctor method and tested for vertical creep with one-dimensional oedometer compression tests at three stress levels to simulate different depths behind an MSE wall. Large-scale test pit testing was performed to determine reinforcing strip ultimate lateral pullout strength; pullout creep at 25%, 50%, and 75% of ultimate pullout; and vertical creep at the three overburden stress levels used in laboratory testing. RAP–sand blends had higher density, friction factors, and pullout strength and developed ultimate pullout strength at lower displacements than either 100% sand or 100% RAP. The RAP–sand blends exhibited more horizontal and vertical creep than 100% sand but significantly less creep than 100% RAP.