Distress: severe cracking and pavement oxidation; critical condition roads
Obstacle: quick and efficient repair at low-cost
How can Ergon A&E help: eScrub rejuvenating chip seal and mass crack treatment
Fallen Through the Cracks
Independence County, Arkansas, a highly agricultural community located approximately 60 miles northeast of Little Rock, was experiencing a rapid decline in the condition of many of its roads. Major swings in temperature and higher than average rainfall created havoc for roadways. Major flooding events left little funding for infrastructure maintenance, while their Pavement Condition Index, or overall rating for road conditions, continued to tumble, leaving more roads in dire need of repair than available funds to maintain them. Roads throughout the county, many carrying heavy live-haul and logging traffic, began showing near irreparable levels of cracking. Something had to be done.
After experiencing disappointing results with single chip seals, which tend to bridge over cracking of this degree rather than provide a fill and repair, the County was desperate to find an effective remediation solution for their extensive cracking and pavement oxidation woes. The goal was to effectively repair as many critical roads as possible in a short time frame, meaning funds would have to stretch a long way. Distress of this nature is ordinarily too severe for pavement preservation treatments to handle, warranting more intensive, higher-cost treatments. Conventional methods would prescribe a mill and fill solution where the top one or two inches of asphalt are milled and removed from the road surface and new hot mix is laid in its place. At an average national cost of $9-$10 per square yard, Independence County needed a more economical, yet uncompromising solution. Ergon Asphalt & Emulsions, Inc., (Ergon A&E) Area Sales Manager, Darryl Gardner, set up meetings with County Judge Robert Griffin and County Road Foreman Ron Byars to offer his expertise. After personally inspecting the roadways, several of which were in critical condition, he recommended eScrub as a solution to their major cracking issues.
eScrub, part of the e-Series family of pavement preservation and maintenance products, is a rejuvenating chip seal and mass crack treatment that restores severely cracked, oxidized travel surfaces, instantly. eScrub employs a simultaneous apply-and-scrub method where a highly-modified polymer emulsion is distributed over the distressed road surface followed immediately by a broom sled. The broom sled forces the emulsion into cracks and disperses it evenly across the surface. eScrub’s highly modified CMS-1PC rejuvenating emulsion goes beyond the capabilities of ordinary chip seals, rejuvenating the underlying asphalt’s quality and durability in the process. An aggregate layer is immediately applied and embedded into the emulsion using a roller, creating the driving surface. eScrub is also economical in that it can compete with higher-cost repair treatments, such as mill and fill, with exceptional results and at a fraction of the cost with national averages around $2.65 per square yard.
First-Hand Evaluation of eScrub
Having no room for financial error, county officials were hesitant to initiate a major project with an unfamiliar product. Understanding this concern, Darryl arranged for Ron and Billy Cummings, a local contractor, to observe a north Mississippi eScrub project so they could witness the process for themselves. In addition, he took them to locations where eScrub had been utilized on past projects to observe its resiliency to weather and heavy loads years after application. Ron was pleased with the results and agreed it was the best course of treatment to try in Independence County.
The date for construction on the 1.5-mile-long Thompson Drive, was set for May 19, 2015; it was warm and sunny, lending a perfect environment for application. Cummings Chip Seal of Batesville, Arkansas, was in place to administer the treatment. Darryl arranged for a broom sled from Texas to be brought in for the application and he was on-site for the duration of the project to assist with equipment calibration and serve as an on-the-job resource to the contractor and agency.
Emulsion was applied at a shot rate of 0.28-0.31 gallons per square yard. Adjustments were made after noticing the emulsion was completely absorbed into leveling patches that had been installed prior to construction. In ideal situations, use of a localized spot chip or fog seal would be used to provide a barrier atop the patches to prevent absorption, as the patches are typically porous in nature. A single layer of 3/8-inch minus cover aggregate, provided by Bradley Contracting, Inc., was applied at a variable rate of 22-28 pounds per square yard, followed by dual pneumatic rollers, preparing the final travelling surface. The mass crack sealing process, which would have taken more than a month and untold man-hours to complete manually, was finished with traffic returning to the surface in just over four hours.
The agency was so impressed with the final outcome, that the remaining emulsion was used on short sections of several other roads with severe cracking, totaling approximately five to six miles of total application.
Independence County was the first county in Arkansas to use this pavement technology and proved it could responsibly and effectively remediate roads without overextending county maintenance funds and labor resources. With the successful installation of eScrub, they expect a 6-7 year extension in the life expectancy of Thompson Drive and now have a solid foundation for future pavement preservation treatments, which will continue to save the County in the long run. With tens-of-thousands of taxpayer dollars saved on this single project, they can stretch their remaining maintenance and repair funds into more diverse road projects across the county. County representatives said they plan to evaluate eScrub’s extended performance through the winter months and rainy season with hopes of broadening use of the treatment beginning in 2016.