Contractors must identify, define and overcome obstacles on every job. Intermountain Slurry Seal recently did just that to successfully microsurface a busy 15-mile California highway at night.
In recognition of this achievement, the Salt Lake City, Utah-based contractor was honored for a second straight year with the International Slurry Surfacing Association (ISSA) President’s Award.
By knowing its equipment, employees and the process, Intermountain Slurry Seal overcame darkness, heavy traffic and strict working and environmental requirements to place a microsurface—a new wear surface with greater skid resistance—on 15 miles of U.S. Rte. 76 just north of San Diego. Intermountain Slurry Seal applied microsurfacing to about 254,118 sq yd of roadway, using Bergkamp Inc.’s M1 Continuous Paver to preserve the existing roadway for several more years.
“[Public] agencies are better off taking care of their best roads first,” said Rusty Price, general manager of Intermountain Slurry Seal’s Utah branch. With the company for more than 23 years, Price has been involved in all aspects of the company’s business. His involvement has contributed to the company’s 20-year growth and expansion into a large part of the western U.S.
“The whole concept behind preservation is putting the right treatment on the right road at the right time,” said Price. “It saves you a lot of money in the future. Preservation costs $2-3 per sq yd, while a 4-in. mill-and-fill costs about $15-17 per sq yd. You can preserve the pavement twice in the time that you would mill-and-fill once and save tremendously.”
A difficult yet gratifying job
The Utah and California operations of Intermountain Slurry Seal worked closely with the California Department of Transportation (Caltrans) to complete the project in a timely manner and still meet all requirements. The California-area operations managed the project by working with Caltrans, traffic control and pavement-marking subcontractors on scheduling and contractual agreements, while the Utah operations used its equipment and crew to lay the new surface.
Caltrans had specified that this microsurfacing job must be handled using a continuous paver. Intermountain Slurry Seal used Bergkamp’s M1 continuous paver, because when used with mobile support units it lays material for long distances without stopping, thus reducing construction joints.
The U.S. Rte. 76 project was located within the Pala and Pauma Indian Reservations, which had three large casinos that also host concerts and other gaming events.
“Route 76 still had its original chip seal surface that was placed about 10 years ago and was starting to show signs of raveling and aging,” said Price. “The microsurface improved the quality of the highly traveled road and protected it against further deterioration.”
Intermountain Slurry Seal’s crew could work only between 9 p.m. and 6 a.m., Sunday night through Friday morning. The job consisted of sweeping off the 15-mile road, fog sealing the shoulders and removing all of the striping and reflective pavement markers. Then the crew microsurfaced 13-ft-wide paths in each travel lane.
“Microsurfacing is very challenging at night, and honestly there was more traffic on the road at night than during the day,” said Price. “We could only control two miles of the road in one lane at a time, so we would often bump up our traffic control to stay within those regulations.”
With as many as 1,000 cars on the road at one time during work hours, Intermountain Slurry Seal emphasized safety. Daily safety meetings were held to eliminate danger to both the workers and oncoming traffic. There were no accidents during the job.
The right stuff
Intermountain Slurry Seal finished the project ahead of schedule despite using an aggregate source it had never used before. The Type III aggregate—received from Coachella Valley Aggregate in the Palm Springs, Calif., area—was put through extensive testing. In order to be classified as Type III, a specific percentage of the aggregate had to successfully pass through eight different-size screens.
“We use a 1,000-gram sample of the aggregate and run it through the screens, weighing it before and after to see if the end product meets specification,” said Price. “Type III aggregate is a ‘beefier’ product than Type II and is the most common aggregate used for highways and other large projects.”
Intermountain Slurry Seal uses five ingredients in the microsurfacing mix:
- Polymer-modified emulsion (65% asphalt, 35% water and emulsified chemicals);
- Type III aggregate;
- Mineral filler (portland cement, hydrated lime or other chemicals);
- Water; and
- Additives (optional, used at operator’s discretion for break control).
Bergkamp’s M1 continuous paver has a separate compartment for each of these ingredients. At the flip of a switch, the ingredients are delivered at metered rates into the pugmill, where they are mixed and transferred to a hydraulically adjustable, variable-width spreader box. The augers in the spreader box spread the mix throughout the box and onto the road. Mobile support-unit trucks hold replacement ingredients and feed the paving machine when it runs low, keeping the machine running constantly and minimizing the number of construction joints in the road.
In all, Intermountain Slurry Seal used the following to complete the project:
- 2.2 million sq ft of Type III microsurfacing;
- 3,081 tons of Type III aggregate;
- 381 tons of microsurfacing emulsion;
- 800 90-lb sacks of Type I cement; and
- 16 tons of concentrate fog seal.
Intermountain Slurry Seal also took extra environmental precautions to prevent the leakage of asphalt or chemicals into the environment—including laying down tarps to absorb excess material during cleaning. After the project was completed in fall 2006, Caltrans was pleased with the new pavement and Intermountain Slurry Seal’s attention to the environment.
“I am quite satisfied with the professionalism that the Intermountain crew exhibited,” said Todd Traunero, transportation engineer for Caltrans District 11. “Their knowledge and attention to detail played an important role in the success of this project.”
—contributed by Bill Cooper, Bergkamp director of sales and marketing