During its 30th annual meeting in Palm Springs, CA, the Asphalt Recycling & Reclaiming Association (ARRA) announced the recipients of its Annual Awards for Excellence, given this year to two public officials, in two of the technical disciplines represented by the organization. Candidates for this prestigious award are typically public officials or specialists in the field of asphalt recycling.
Joseph F. Peterson, district materials engineer, North Region California Department of Transportation was presented the Excellence in Full Depth Reclamation Award.
Three years ago, Peterson was the first California State Engineer to promote cold foam full depth reclamation (FDR). This was the only form of recycling other than cold planing conducted by the state of California Department of Transportation (Caltrans) in the past 15 years.
During the past three years, Peterson, has promoted and educated within Caltrans the benefits of recycling and reclamation.
In 2005, because of his efforts, three cold foam FDR projects were completed by Caltrans along with two other projects entering the design phase.
Peterson served as the design engineer and as Caltrans quality control advisor on all of these projects. He also was the writer of the original cold foam FDR specification within Caltrans and conducts all the reclamation and recycling training within Caltrans, currently having completed training within six of the 12 Districts.
In 2003, Peterson was selected to serve as co-chairman of the recycling sub task group of Caltrans Pavement Preservation Task Group (PPTG). The PPTG is a volunteer group of Caltrans and Industry professionals for the sole purpose of improving the procedures, techniques and products used within the state of California for maintaining highways.
Peterson currently has two projects in design within his district for CIR using the new specification.
In 2005, Peterson had already recommended and promoted a contractor substitution to the Interstate Highway 80 project for the use of CIR with cold foam and cement slurry-binding agent instead of the original designed conventional mill and fill. The project encompassed 34 lane mi. and 48 shoulder mi.
Peterson served as the original design engineer and acted as the state’s consultant and quality control representative in 2005 on the San Luis Obispo County/Santa Barbara County Highway 33, a cold foam in place recycling project, complex and involving several grade and material changes throughout.
The shoulders were recycled continuously with the mainline using two staggered foaming reclaimers. Peterson ensured that every difficulty that arose in the field was met with decisive actions and ultimate success.
Joe Schroer, field materials engineer — Central Materials Lab, Missouri Department of Transportation received the Charles R. Valentine Award for Excellence in Cold In-Place Recycling.
In the recent past, visitors to northwest Missouri state or taking a break at Mozingo Lake may have traveled on the four-lane route of Highway 71 in northwest Missouri. This particular highway connects St. Joseph, MO, to the growing city of Maryville, MO.
Heading north from St. Joseph the asphalt pavement was in need of rehabilitation. But, with the Missouri Department of Transportation (MODOT) dollars being very limited, it decided to look for alternate ways to reconstruct this stretch allowing them to cover more miles with fewer dollars. That is where the idea of Cold In-Place Recycling and Full Depth Reclamation came into effect.
MODOT had not utilized Cold In-Place Recycling (CIR) or Full Depth Reclamation (FDR) in the past, but it was discovered that these processes could be used to solve a number of problems.
Traditionally, MODOT had designed projects to mill off aged hot mix and replace with new Superpave mix, or simply add layers of mix to the existing pavement. Local aggregates had been readily available with numerous hot mix suppliers giving very competitive prices. But hot mix asphalt usage had increased tremendously, liquid asphalt prices were going up and aggregate availability was dwindling.
Due to the realization of these problems, the MODOT Central Materials Lab in Jefferson City, MO, became more familiar with CIR and FDR through research of other states usage, including Kansas and Nevada. It was recognized that not only could these processes save them money, but also they could reuse existing materials, have an engineered mix design, utilize performance related testing, and use an emulsion that was produced specifically for each project.
Discussions with asphalt emulsion suppliers, recycling contractors, and consultant engineers, along with information received from other state agencies, gave MODOT enough information to begin pursuing its first project. Highway 71 was No. 1 on the list.
This particular project addressed 7.2 mi. of the northbound lanes of Highway 71 from Pumpkin Center (Route A) to the end of the divided highway, which approaches the city limits of Maryville. The reason this project was selected was because of the ability to use both processes, CIR of the main driving lanes and FDR of the shoulders.
This was determined by coring the driving lanes and sampling and testing the shoulders to understand what materials were present and the quality of those materials. This section was comprised of a composite pavement of the driving lanes with 5 to 7 in. of hot mix over concrete, and the shoulders had 2 in. of hot mix over aggregate base.
The project was let in January 2005 and awarded to Herzog Contracting Corporation of St. Joseph, MO. Herzog chose Brown and Brown Inc. of Salina, KS, as its subcontractor to perform the CIR and FDR.
SemMaterials, LP of Tulsa, OK, performed the mix design using existing materials from Highway 71. SemMaterials also supplied Brown and Brown an engineered emulsion from its Salina facility to inject into the 6 in. of material on the shoulder.
Brown and Brown began the shoulder work in June 2005 with its CMI RS-650 to reclaim 4 in. of base and 2 in. of hot mix. The material was then compacted with a padfoot roller and profiled with a motor grader.
The shoulders were then completed with a Dynapac pneumatic-tire roller and a Caterpillar double steel drum roller. Once the shoulder work was completed, Brown and Brown addressed the main driving lanes using lime slurry and SemMaterials engineered emulsion to recycle the existing 4 in.
The CIR train was comprised of a Caterpillar PR 1000 milling machine, screen and crusher unit, pugmill, and a Blaw-Knox PF110 paver. Following the paver were the Dynapac and Caterpillar rollers used for compaction. Upon completion of the recycling, Herzog finished the project with a 1.75-in. Superpave hot mix. The completed project was a success.
“On this seven mile project we saved about $600,000 on the shoulders alone. So, for seven miles, to get that kind of savings was a big benefit to us here in District 1,” said Troy Slagle, operations engineer of MODOT District 1.
Reduced cost, early strength and performance, ability to reuse existing materials, and engineered designs have given MODOT reasons to pursue additional projects to utilize these recycling techniques.