Open House Features Site Tour of Douglas County Concrete Pavement Preservation Project

On Oct. 3, The PCA Rocky Mountain Region, Colorado/Wyoming Chapter of the American Concrete Pavement Association and the International Grinding & Grooving Association (IGGA) co-hosted an open house on concrete pavement preservation (CPP) in Highlands Ranch, Colo. The open house featured a site tour of one of the largest CPP projects to ever have been undertaken by a county entity.

The CPP project was carried out across various arterial and collector roadways throughout Highlands Ranch in Douglas County. The urban location, which included area businesses and local access to homes, made for a unique set of challenges. While the Federal Highway Administration, along with various state Departments of Transportation (DOTs), have well-established processes in place for CPP, local governments often have limited experience with state-of-the-art CPP methods. It is therefore of critical importance that when local governments embark upon preservation efforts, they manage the process carefully. The Douglas County Department of Public Works Engineering in Colorado achieved success by inviting industry members to weigh in early and establishing a firm plan before work got underway.

“While Douglas County does have an aggressive Pavement Management Program utilizing some of the best management tools, it was a question of the concrete pavement’s age and rideability, or smoothness, that brought this project to the top of their list,” said Darrell E. Roberts, Engineering Permits, Inspections & Utilities Manager with the Douglas County Department of Public Works Engineering.

The Highlands Ranch metropolitan area had significant stretches of roadway that were reaching the end of their design life, ranging in age from 25 to 30 years old. With this aging pavement, it was critical that the county do some research prior to the project that also included a review of options available to fix the problems. A forensic study was conducted on five different sections of concrete roadways within Highlands Ranch, with one of the sections showing no issues and the remaining four showing issues including broken panels, joint separation, transverse faulting and cracking.

“Once the report became available and the problems were identified, the county held several conferences with different agencies to gain an understanding of options to fix the problems with a long range goal of reduced maintenance,” said Karl Lucero, Pavement Management Engineer with the Douglas County Department of Public Works Engineering.

Douglas County has performed CPP in the past on several small areas and achieved good results, and was therefore looking to increase the use of CPP and affect a larger percentage of their network using the knowledge gained on those smaller projects. The county chose to make the standard repairs using a remove-and-replace system on all broken concrete with the addition of transverse dowel bars in locations where there were none. Grinding, followed by a very aggressive joint sealant program, was identified as a second phase of the CPP, with the intent of smoothing out the ride.

Existing conditions were a 7.5 inch thick concrete pavement with longitudinal joint spacing at 12 feet and transverse joint spacing at 15 feet. The pavement was showing transverse faulting. The total length of concrete to be repaired was sixty-six lane miles, distributed across two sections with seven lanes and five sections with five lanes. Preservation techniques selected for the project included diamond grinding the surface of the existing pavement (500,000 square yards), sawing and sealing of concrete pavement joints (1,058,400 linear feet) and replacing all pavement marking (using 2,430 gallons of pavement marking paint and 5,385 square feet of methyl methacrylate). Douglas County engineers are also interested in comparing beginning and ending IRI values for the project.

Project costs were $5 million for concrete panel removal and replacement and $3.5 million for grinding, joint sealant and striping. The work was performed with a 90 calendar day contract for each project. The estimated completion date is Nov. 24, 2013. Area taxpayers and businesses will benefit from the goal of improved ride quality and pavement longevity which this project will provide.

“From start to finish, the Douglas County Department of Public Works Engineering has executed this project in a deliberate and competent manner,” according to John Roberts, Executive Director of the IGGA. “Their use of comprehensive pavement management tools, coupled with a solid investigation of all the concrete pavement preservation options, will lead to smooth, safe and long-lasting roadways, benefitting motorists and taxpayers for many years to come.”

About IGGA

The International Grooving & Grinding Association (IGGA) is a non-profit trade association founded in 1972 by a group of dedicated industry professionals committed to the development of the diamond grinding and grooving process for surfaces constructed with Portland cement concrete and asphalt. In 1995, the IGGA joined in affiliation with the American Concrete Pavement Association (ACPA) and in 2012 formed the IGGA/ACPA Concrete Pavement Preservation Partnership (IGGA/ACPA CP3). Today this partnership serves as the technical resource and industry leader in the marketing of optimized pavement surfaces, concrete pavement restoration and pavement preservation around the world. The mission of the IGGA is to serve as the leading technical and promotional resource for the acceptance and proper use of diamond grinding and grooving as well as PCC preservation and restoration. For more information, visit www.igga.net.

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Image captions:

1) Concrete pour begins at the open house on concrete pavement preservation (CPP) in Highlands Ranch, Colo.

2 Work on the stretch of pavement is completed.

3) Attendees gather at the open house to discuss CPP techniques

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