Development of Hot Mix Asphalt Pavement Performance Properties for Long-Life Pavement Design: Caltrans District 4, Interstate-80 Solano County, California

In the period 2012 to 2014 Caltrans designed and built three long-life asphalt pavement (LLAP) rehabilitation projects. Two projects were in District 2 on Interstate 5—one just north of the city of Red Bluff and the other on the interstate running through and north of the city of Weed—and one in District 4 on Interstate 80 in Solano County between the cities of Dixon and Vacaville. This technical memorandum describes the processes by which performance criteria were developed for a pavement section that is part of the LLAP project on Interstate 80. This pavement section, designed and constructed as an LLAP section, consisted of the following pavement components: A hot mix asphalt (HMA) surface course containing a polymer-modified asphalt (PG 64-28PM) with 15 percent reclaimed asphalt pavement (RAP) and a representative virgin aggregate from the local area treated with 1.2 percent lime (marinated). An HMA intermediate course containing a conventional asphalt binder (PG 64-10), and the same lime-treated aggregate as the surface course plus 25 percent RAP Caltrans headquarters staff from the Office of Asphalt Pavement designed the structural pavement sections using material parameters developed from AASHTO T 320 shear testing and AASHTO T 321 fatigue and stiffness testing results. Pavement design for the Solano project made use of the same mix parameters as those used for the design of the Caltrans District 2 Interstate 5 Red Bluff project but with traffic and climate data specific to the Solano site. In addition to the AASHTO T 320 and T 321 results used for the design and performance-related specifications, results from AASHTO T 324 Hamburg Wheel-Track Testing (HWTT) were required in the performance-based specifications as a consideration for moisture sensitivity. The HWTT results were not used in the design process.