National Concrete Pavement Technology Center

Project description

Many states have adopted the use of recycled pavement layers in highway rehabilitation. Techniques such as full depth reclamation (FDR) with or without stabilization additives, plant mix cold recycled asphalt pavement (RAP), blending RAP with unbound sub base layers and substitution of unbound sub base layers with RAP are being used effectively. However, the properties of these recycled pavement layers change significantly with variations in temperature and moisture conditions during different seasons. To obtain good performing rehabilitated pavements throughout their design lives, it is imperative to select the best combination of virgin materials, recycled materials, stabilizing additives and construction methods for a particular location. For such selection, an understanding of the in-place properties of pavement layers and their relationship to the principal pavement response mechanisms is needed. Currently, significant knowledge gaps exist regarding variations in performance related properties that result from seasonal changes in temperature and moisture content. The main objective of this research is to determine the in-place properties of pavement cross-sections containing recycled materials common to the New England region, and to relate changes in those properties to variations in temperature and moisture. The study will focus primarily on obtaining field data from base layers (as opposed to asphalt surface layers) that have been constructed with different types of unbound or bound recycled layers such as full depth reclamation (with or without stabilizing additives), plant mix recycled asphalt pavement (PMRAP), or foamed asphalt. The research team will work with the New England Transportation Consortium (NETC) advisory board members to identify appropriate field sites where the pavement design is clearly documented and where pavement performance can be linked to factors such as traffic loadings, moisture regimes and freeze-thaw effects. Laboratory testing will also be included to complement the analysis of in-place test data and instrumentation monitoring.