Wednesday | September 20, 2017

API Takes on Full Recycling

Ind BeforeRaveling

The east limit of County Road 800S after the full depth reclamation and hot mix asphalt paving project shows a smooth finished surface for Steuben County’s motorists.

County Road 800S in Steuben County had seen better days. Anthony Jarem, vice president of Soil and Materials Engineers, Inc., (SME), Kirtland, Ohio, explained that the road’s original aggregate base was a bank-run, rounded material that didn’t have a good, angular interlock. He said the surface’s last preservation treatment was about 10 or 12 years ago, but that repair hadn’t addressed the underlying problem of swampy ground and peat deposits that don’t offer a good sub-base.

According to Mark Cox, regional manager for The Klink Group, things were only going to get worse. The average daily traffic (ADT) on the 4.5-mile stretch of roadway was between 2,000 and 4,000 with 15 percent of that truck traffic. “The ADT is estimated to increase to 5,000 in the next five years with the truck count increasing to 30 to 40 percent due to the eastbound traffic from the new Family Dollar distribution center and the growth of Hamilton’s industrial park,” Cox reported.

It was time to address the problems of the existing pavement, which Cox reported had an estimated 40 to 45 percent failure in the sub-base and asphalt layer. According to his report, CR 800S had major rutting in the pavement and edge failures one can see in the image (at left).

Steuben County officials looked at new construction estimates in the ballpark of $5.5 million but Cox said engineers estimated a full depth reclamation (FDR) with hot mix asphalt (HMA) paving could come in around $2.3 million. API Construction Corporation, LaOtto, Ind., won the bid at a little more than $1.3 million, saving the county 75 percent in funds over new construction and using in-place materials. Here’s how they did it.

FDR - Cement Till Inspection

Engineers at Soil and Materials Engineers, Inc., designed a full depth reclamation process for the CR 800S project. The team from The Klink Group pulverized the existing roadway, and then reclaimed it with chemicals churned in with a WR2400 from Wirtgen. API Construction workers rolled the reclaimed surface and gave it five calendar days to cure before hot mix paving began.

“This project is unique in the fact that it used a FDR construction process instead of the conventional pavement removal and replacement,” Tom Johnson said. He’s an estimator and project manager as well as the quality control (QC) representative for API Construction. “This construction process is less expensive, has a much shorter construction window, minimizes the impact to the traveling public, and is greener due to the reclaiming of the existing pavement section requiring less equipment and therefore emissions, and virtually no spoils or waste materials to dispose of.”

Johnson called the job “recycling on a massive scale” with good reason. First, SME designed the FDR process for the road and the subcontractor The Klink Group came in to work on the FDR in place. “Soil and Materials Engineers performed the initial soil borings for the evaluation process for the pavement design, as well as the in-place sampling and testing of the FDR for proper cement content, water-cement ratio, density and till depth verification,” Johnson said. “The Klink Group not only performed the FDR construction process, but placed the seal coat material and hauled asphalt for us on the high production days.”

SME’s Jarem said the county already owned the materials in the roadway, which presented a cost savings right off the bat. The Klink Group merely had to pulverize—Aug. 1 through 3—and mix those materials with some chemical additives, which they began Aug. 6, to enhance the road base’s properties.

“Although API Construction did the fine grading and final compaction of the FDR, the actual pulverization, cement till and initial sheep-foot rolling operations were completed by The Klink Group,” Johnson said.

Shoulder drop off on LA 466

The shoulder drop off on LA 466 shows the steep pavement edge that agencies and DOTs wish to remove from rural roads to make safer surfaces for the traveling public. By placing a sloped pavement edge along such roadways, the agencies provide a smoother transition for motorists who accidentally veer off the main line and make corrections to get back into the travel lane. Photo courtesy of Prairie Contractors

Once the FDR section was built, API Construction paving crews had to wait at least five calendar days for it to cure before they sprayed a tack coat at a rate of approximately 0.03 gallons per square yard. Starting Monday, Aug. 13, they placed the HMA base—an INDOT Type B 19-mm Superpave mix—3.5 inches deep. The base mix was designed with a PG64-22 binder in which API incorporated 15 percent RAP.

Between the base and surface courses, they sprayed another tack coat at 0.03 gallons per square yard. The surface course was an INDOT Type B 9.5-mm Superpave mix placed at 1.5 inches. It also used the PG64-22 binder, but incorporated 25 percent RAP.

To get a smooth surface, Johnson credits HMA Field Superintendent Kary Benson and Scott Fenstermaker from API’s testing department for working closely together to keep the project flowing. “Between these two individuals and their communication and cooperation, we were able to produce a consistent quality mix that not only achieved very good test results, but also performed well on the lay-down end without segregation, tearing, stripping, etcetera that can oftentimes occur. We also achieved production rates that were expected.”

The crew ran the plant at an average of approximately 160 tons per hour (TPH). The paving crew used a Blaw-Knox PF 3172 paver with a material management kit and a ski modified with a mat-reference system to place 17,344 tons along nine lane miles in 10 days. They used a Bomag BW266, an Ingersoll-Rand DD90 and a Volvo DD-112 to get densities that they monitored in the field with a TransTech PQI and in the lab with core samples. Overall, the density results averaged 92.4 percent for the 19-mm base and 92.6 percent for the 9.5-mm surface.

“The [finished] typical cross-section pavement design for CR 800S consisted of 1.5 inches of HMA 9.5-mm surface on 3.5-inches of HMA 19-mm base, which were placed on 16 inches of full depth reclamation…thus having an overall thickness of 22 inches,” Johnson explained.

Cox explained how the pavement thickness was reduced overall. “If you look at a mechanical empirical value applied to the FDR section using a conservative structural co-efficient value of 0.2 per inch, we provided an equivalent new HMA value of 9 inches plus 5 inches of new HMA, which equals a cross-section equal to 14 inches of new HMA.”

Ind Huntertown Plant

API Construction’s primary plant is the ADM Milemaker 275 in Huntertown. It has two 200-ton capacity silos and a higher production capacity than their plant in Angola. It’s located about 30 minutes from the CR 800S project.

To complete so much work in such short order, it takes cooperation. “I can’t say enough about how fortunate we were as a prime contractor to have a great group of subcontractors such as Mark Cox, Jane Cox and Robert Creamer of The Klink Group; John and Karen Haan for signs; and Greg Lowe of The Airmarking Company for the pavement markings, which were all cooperative, knowledgeable and very timely with our set construction sequence of operations and schedule.

“Lastly, hats off to the Steuben County Commissioners Ron Smith, James Crowl and Loretta Smart for their timely assistance and guidance. Steuben County’s Highway Superintendent Ken Penick championed the idea by allowing a ½-mile FDR test project in 2011. And a very special thanks to Ken Herceg, Brian Thomasen and Adam Bowden of Ken Herceg & Associates for their quality design, project coordination, on-site inspection, engineering and for being such a valuable asset to the project and its success. The CR 800S FDR and HMA paving project is something everyone can and will be proud of for many years to come.”

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