Sand seals: 60% savings
For paved roads, the department is also using the product in sand seals for rapid crack-filling and to rejuvenate oxidized pavement.
The smooth scrub/sand seals are covered after a few years with a CRS-2P chip-seal for the next maintenance cycle/treatment. Because the sand seal acts as a stress-absorbing interlayer, the pavement requires fewer subsequent surface treatments.
Finished application. The sand seal creates a stress-absorbing interlayer that keeps the underlying cracks from returning and surface moisture from causing further damage to the underlying road base. As part of routine maintenance, the Luna County Road Department can place a conventional CRS-2P chip seal on top as a final wearing course.
This is saving almost 60% per lane mile compared to the legacy method of crack filling and sealing.
“In the past, we’d let the roadway get bad and go in with cold mix to patch,” he says. “But we developed a strategy for bringing in minus-quarter-inch rock, including sand and fines, depending on the size of the cracks, and scrubseal and crackseal in one pass. We did scrub/sand seals on some ranch roads years ago and haven’t needed to do further maintenance for 15 years at a time, even with tens of thousands of trucks using them.”
Sealing the cracks and developing the proper application rate is more art than science, but having a forgiving product helps.
“You can vary the application rate depending on the road condition,” he says. “Typical application rates for emulsion are about 0.30 gallons per square yard, but with PASS we sometimes go to 0.15 or 0.2 gallons per square yard and still get excellent performance. If the road needs it, you can put more on; but you can go way down on the application if called for.”
On paved roads in good condition, the department is maintaining pavement condition indexes (PCI) using PASS QB (quick break) rejuvenating fog seals.
“All of our paved roads were heavily oxidized by heat and sunlight; the UV penetration particularly strips out a lot from the asphalt,” says Miller. “The PASS QB helps rejuvenate and restore the balance to the asphalt, adds residual asphalt to the surface, seals the pavement from microcracks, and improves the appearance and delineation of the road.”
Reaping budgetary rewards
Leveraging in-house equipment and crew, the department has applied treatments consistently over the years while keeping a watchful eye on roadway condition.
Such vigilance pays off.
The department’s program helped Luna County earn special recognition from the governor’s office for sustainability.
“The state allocates us a fixed amount for maintenance projects,” Miller says. “We stretch those dollars to complete additional preventative maintenance, which is good for everyone.”
Phil Vandermost is vice president, marketing and government relations, for Western Emulsions Inc. E-mail firstname.lastname@example.org. Visit www.westernemulsions.com.