A stretch of Highway 52 near San Diego, California, was in such rough condition that it was deemed unsafe for drivers. The California Department of Transportation called for emergency repairs and shut down the stretch of road for 48 hours. Multiple contractors, including RDO Equipment Co. customer Pavement Recycling Systems (PRS), were assembled to complete the job.
A busy route many Californians frequent, the troublesome stretch of Highway 52 suffered from slope and drainage issues and severe roughness. The reconstruction project outlined extensive repairs in a short period of time. Enter the latest in intelligent paving technology.
Ben White, Topcon product manager for RDO Equipment Co. and former PRS technology manager, became involved to support PRS’s use of these innovative paving products. He described the complexity of the project and the high level of coordination required among contractors.
“The part of the highway with the most wear and tear was built on an old landfill,” White said. “This caused problems because the sub-grade moves and compromises the road structure and surface.”
White said the road is a continual problem, with officials calling for temporary emergency fixes every few years. This time, the decision was to remove a substantial amount of road surface and create a longer-lasting repair.
After recognizing that traditional milling methods using local and global positioning systems would require too much time and not correct underlying issues, the team turned to 3D scanning, modeling and automated machine guidance (AMG).
Equipped with the Topcon SmoothRide™ intelligent paving system, the team was able to quickly capture a detailed model of the road using a vehicle-mounted scanner capable of collecting data in live traffic at typical highway speeds. The model is built with millions of GPS points, enough detail to create a design optimizing smoothness, grade, thickness, line work and other constraints.
PRS and RDO team members fed the road reconstruction’s design into five Wirtgen 210i milling machines, each outfitted with SmoothRide™ automated machine guidance, which allowed them to simultaneously mill the road surface with unmatched precision. In the end, the project was completed in a single weekend, resulting in a 70% improvement in the smoothness of the road.
This highway’s reconstruction efficiency caught the Transportation Research Board's (TRB) attention as it demonstrated the possibilities when contractors successfully implement intelligent paving technology.
“This project was an opportunity for us to conduct research in real-time in a crucial setting,” White said. “We were able to show how intelligent paving technology can be a perfect fit for certain projects, resulting in better, longer-lasting roads.”
White and Tony Carden, RDO roadbuilding product manager, submitted the project research and strong results to the Transportation Safety Board (TRB) in collaboration with PRS.
TRB accepted the paper, and the group was invited to present the research in person in Washington, D.C. The TRB is a division of the National Academy of Sciences, Engineering, and Medicine, providing leadership in transportation improvements and innovation.
“Paving specifications are getting tighter every year, and with new states requiring things like intelligent compaction and thermal profiling, contractors are being challenged to work differently,” Carden said. “Intelligent paving technology is designed to help; it’s just a matter of demonstrating and educating through projects like Highway 52.”