California’s quest to construct higher quality and longer lasting roads

Location of Project

State Route 138 is an east-west highway generally following the northern foothills of the San Gabriel Mountains of southern California, USA from its junction with Interstate 5 south of Goman eastward to Mount Anderson Junction, its eastern junction with State Route 18 south of Crestline in the San Bernardino Mountains. Except for the western two miles of the route between Interstate 5 and just east of Gorman Post Road and a segment shared with State Route 14 between Avenue D in Lancaster and Palmdale Boulevard in Palmdale, it is all surface road, mostly undivided two-lane road.

Project Details

• Phase 1: December 2006 Phase 2: April 2007
• ½ Mile in length
• 80 Feet wide
• 2 different modified basecourse depths: 240mm & 160mm
• Wearcourse: 60mm Type A mix
• Total modified mix: 11,000 Tons

Objectives of Pilot Program

• Evaluate the bidibility, buildibility, constructibility, and performance of the material specified by the specification;
• Evaluate the applicability of current mix design procedures, and QC/QA specifications;
• Ensure that during production the resilient modulus of the hot mix asphalt base achieves the levels specified in the specification;
• Confirm that aging of the modified asphalt binder can be controlled during the construction process;
• Evaluate in-service aging, and hardening to determine that these will not cause premature cracking of the pavement;
• Obtain unit cost information for project estimating purposes;
• Obtain material samples and collect material information that will allow the Gravel Equivalent Factor to be determined for the base material specified by this specification; and,
• Collect additional project information, and material data that assists the analysis to be performed under the long-term objective.
• Determine effective pavement strategies that can control the in-service aging, and hardening of the modified asphalt binder;
• Characterize the material properties so that principles of engineering mechanics can be used to analyze thickness design
• Determine whether or not the modified hot mix asphalt base can be represented by equations typically used to describe the fatigue behavior of hot mix asphalt bases containing neat asphalt binders; and,
• Understand the distress mechanism so that distress/transfer functions can be developed for low temperature cracking (if used under thin surface courses), repeated load fatigue, and permanent deformation.