During 2022, County Engineer Tony Hinkle reached out to Heritage Research Group (HRG), to have Waverly Park Road in Morgan County, Indiana, be sampled for a potential recycling project. The results from pavement sampling determined that the road was a candidate for a 4-inch Cold In-place Recycling (CIR) treatment. Based on the report’s recommendations, Hinkle made the decision to move forward with the CIR treatment to repair and preserve the pavement.  

Heritage Research Group

Since 1980, Heritage Research Group, our in-house R&D laboratory, has helped The Heritage Group companies, customers, and partners evolve and adapt to an ever-changing marketplace. Today, HRG provides innovative products, processes, and training that constantly improve the way our companies serve their clients and delivers solutions to address the myriad of challenges our clients face. It also creates new technologies that fuel further business opportunities for The Heritage Group.

You can learn more about HRG by clicking here: https://thgrp.com/heritage-research-group/

What is CIR?

CIRis acost effective and sustainable method of constructing a recycled asphalt-bound layer that reduces trucking and construction time, while also saving natural resources. The process mitigates cracking and other distresses within the treatment depth that may remain in the pavement below shallower treatments. CIR is a rehabilitation technique where pavement is milled, crushed, and mixed in place (within the roadway) with an asphalt emulsion and then placed and compacted with conventional paving equipment in one continuous pass.  

Project Background

Waverly Park Road is an old state route (SR-37) just outside of the metropolitan area of Indianapolis. The roadway is just west of I-69 and south of SR-144.  

The pavement sampling performed by HRG found an average of 5.0 inches of asphalt pavement over good-condition concrete. The decision made by Morgan County to treat the existing distress with CIR optimized the resources already owned by the county.  

CIR Project in Morgan County, Indiana

In August of 2022, a project took place in Morgan County, Martinsville, Indiana with CIR technology on Waverly Park Road.

Four and half miles of Old State Road 37 were rehabilitated using CIR, topped with 1.5 inches of HMA overlay. Sales and support teams from Asphalt Materials, Inc., experts from Heritage Research Group, and road crews from Milestone Contractors worked together to bring this sustainable project to life.

The final asphalt pavement structure contained 73% of recycled materials. This collaboration and technology brought residents of Morgan County a rehabilitated road with a short timeline, minimal traffic impacts, and cost savings to taxpayers.  

Morgan County was gracious enough to host a project visit during construction, allowing surrounding County Engineers and Highway Supervisors to witness the CIR process in action. The County shared the benefits of CIR to the visitors and highlighted the technique as a valuable tool for agencies.  

To be able to have a wide variety of visitors out on the project brought workers a lot of pride. The project visit also helped visitors gain a better understanding of the type of rehabilitation and the type of materials that they were placing with that follow-up.  

More About CIR

Unlike Cold Central Plant Recycling (CCPR), CIR repairs and recombines pavement materials without removing them from the project site, hence the term, in-place or ‘on-site.’  This process is designed to only treat distresses that are present in the top few inches of the existing pavement, allowing agencies to leave sound, structural pavement intact below.  

The specialized piece of equipment, a Cold In-Place recycler, creates the recycled mixture, mixing the crushed RAP (Reclaimed Asphalt Product) with engineered emulsion at the target emulsion content to ensure the mix design requirements are met. Quality testing is used to monitor material properties throughout construction. Once the CIR mixture is produced, it is transferred via windrow or conveyer belt to a conventional asphalt paver. The material is then compacted using conventional pavement compaction equipment, resulting in a fully coated and structurally sound pavement.  

Tony Hinkle was a recipient of the 2023 Charles R, Valentine Award for Excellence in Cold Recycling. For the Morgan County, IN Waverly Park Road project in 2022. You can find more information here: