Pavement Recycling: Segments II & III
Segments II and III Base Pavement Goes Green
VDOT is utilizing environmentally-friendly processes and recycled materials in both Segment II and Segment III of the I-64 Widening Project, called Cold Central Plant Recycling and Full Depth Reclamation.
VDOT’s research division, the Virginia Transportation Research Council (VTRC) will study the performance of the pavement recycling techniques by placing a forty-foot section of instrumentation sensors in the right wheel path of the right lane during the construction. The sensors will allow researchers to observe the pavement’s performance during its service life and quantify the response to truck loading. By confirming the performance of these sections during the service life, VDOT will be able to quickly implement these recycling techniques on other projects.
According to VTRC, this is one of the largest pavement recycling projects in the U.S. right now, and will result in an estimated $15 million cost savings total for Segments II and III.
Cold Central Plant Recycling
Cold Central Plant Recycling (CCPR) is being used as part of pavement construction for the new lanes being added to I-64, as well as on the existing lanes that are being reconstructed. CCPR uses reclaimed asphalt pavement (RAP) created from the road millings of construction projects around the region.
To make the CCPR material, RAP and fine stone aggregate are fed into a mobile mixing plant, where the materials are bound together using foamed asphalt and cement, producing up to 180 tons of product per hour. This CCPR mixture is dispensed into dump trucks and hauled to the project site, where crews pave the CCPR on top of a drainage layer and a subbase layer of FDR material and recycled crushed concrete. In total, these first layers of the pavement structure have a total thickness of nearly 18 inches and are almost entirely produced from recycled materials.
Millions of tons of RAP exist in stockpiles around the state. Not only does using CCPR on this project help reduce stockpiles of existing RAP materials, it also reduces the overall cost of project materials and environmental impacts.
Wacth a video showing the CCPR process being used on Segment II below:
Full Depth Reclamation (FDR)
Full Depth Reclamation (FDR) will be used as part of the reconstruction for the existing lanes to create the pavement foundation. As part of the FDR process, the existing pavement foundation is pulverized and mixed with cement onsite, and then recompacted into a subbase layer in the roadway. Costs and environmental impacts are reduced by reusing the already available material.
The FDR process is also being used in the new lanes for the recycled crushed concrete subbase layer, which is using imported crushed concrete from other projects. The FDR layer will be covered by a layer of CCPR material.
In the News:
"Recycling Efforts Save Virginia DOT Over $15M on I-64 Rebuild"
Asphalt Contractor Magazine, June 2018
"There's more to I-64 widening project than extra lanes"
Daily Press, August 7, 2017