The University of California Pavement Research Center (UCPRC) has recently published a new research report titled "Cold Central Plant Recycling Study: First-Level Analysis of Heavy Vehicle Simulator Testing".

This first-level analysis research report summarizes the construction and instrumentation of a test track to study the behavior of cold recycled layers containing 100% Recycled Asphalt Pavement (RAP) materials in a pavement structure (recycled in place or through a central plant), a first-level analysis of the results from six Heavy Vehicle Simulator (HVS) tests, and a forensic investigation.

A review of all HVS test data, together with observations from the forensic investigation, indicates that localized shear failures in the aggregate base after heavy rainfall and issues associated with the foaming water and mixing moisture contents in the cold central plant recycled material used in part of Lane 3 on the track had the biggest impacts on test section performance and contributed the most to when and how each section failed.

Research Conclusions:

• Appropriately designed and constructed cold recycled layers will perform effectively in maintenance, rehabilitation, reconstruction, and new construction applications on highways
  
  
• Reductions in life cycle cost and life cycle global warming potential will depend on appropriate recycling strategy selection and pavement designs
  
  
• Optimum foaming water and mixing moisture contents determined during foamed asphalt mix designs must be used during construction to ensure good performance
  
  
• Lower or higher than designed contents will have negative impacts on pavement performance
  
  
• Pavement structures with marginal base course layers that are susceptible to shear failures when wet and/or when subjected to heavy axle loads should be carefully evaluated when designing pavements where resilience is a primary consideration

Read the Full Report