Using Accelerated Pavement Testing to Evaluate Reclaimed Asphalt Pavement Materials for Pavement Unbound Granular Layers

摘要

Unbound aggregate layers are commonly used as subgrade replacement and subbase over weak subgrade soils. With the recent focus on sustainable construction practices, ever-increasing transportation cost, and scarcity of natural resources, nontraditional and locally available recycled materials have become viable for the construction of unpaved and low volume roads. To this end, a research study was recently undertaken at the Illinois Center for Transportation to evaluate the engineering applications and field performances of reclaimed asphalt pavement (RAP) materials used in pavement unbound base/subbase and foundation layers. Twelve different full-scale test sections were constructed for the field performance investigations with accelerated pavement testing. Construction quality control was achieved through in-place density and modulus measurements using field testing. Periodic rut measurements were carried out on pavement surfaces throughout the accelerated loading process. Observed rutting trends in unsurfaced and low volume road test sections were weighed against as-constructed layer thicknesses, penetration-based strength indices, and hot-mix asphalt bulk specific gravity. Among the different field applications, the 60-40% blend of recycled concrete aggregate and RAP materials performed the most satisfactorily as an improved subgrade. Despite exhibiting better relative compaction and higher in situ modulus values, base/subbase layers consisting of 100% RAP were found to be quite susceptible to large deformations during paving as well as wheel-load rutting during trafficking.