Slurry-seal: Months of planning behind summer job
June 23, 2014
As road-maintenance contractors get into full swing with this summer's slurry-seal program in the Truckee Meadows, the engineers who plan the work barely have time to catch a breath before they'll start planning their 2015 schedule.
The Regional Transportation Commission invests about $6 million a year into the application of slurry seal to the region's road network, and the agency says the investment has proven be highly cost effective.
Application of slurry seal — a creamy combination of asphalt, aggregate and mineral filler — costs about 25 to 50 cents per square foot of road.
That's a fraction of the $4 to $5 per square foot that RTC budgets for reconstruction of an arterial that's deteriorated beyond repair, says Scott Gibson, a project manager with RTC who oversees the maintenance program.
Given that RTC estimates the value of the region's road infrastructure — all 315 million square feet of it — at a total of $3 billion, the slurry-seal program protects a major asset.
Staff in the Reno office of Lumos & Associates, a privately held engineering firm, began working in the coldest days of winter to plan the slurry-seal programs that are now beginning with the warm weather.
Recommended Stories For You
Bob Schricker, a project manager with Lumos, explains that analysis begins with a review of the condition of roads throughout the region.
While the worst roads are scheduled for reconstruction or extensive repairs, the Lumos team focuses much of its attention on streets and roads that were built about seven years ago.
That, the RTC's Gibson says, has been shown to be the sweet spot — the point at which a shot of maintenance will do the most to keep a road from deteriorating.
"We're painting the road network black on a seven-year cycle," he says. "The slurry seal retards the aging process."
But the analysis doesn't stop with a review of construction history.
Teams from Lumos & Associates actually walk all the miles of pavement that's planned for slurry-seal maintenance, measuring cracks, looking for spots that need to be patched and taking note of crosswalks or bicycle lanes that will need to be repainted once the slurry seal is down.
It's a chore, but the use of tablet computers and GPS makes the job far easier than the days in which the information was laboriously entered into spreadsheets, says Schricker.
Lumos has been handling the work under contract with RTC since 2003 — an eternity in the development of street mapping and measurement technology. All told, six to eight Lumos staff members work on the slurry-seal program.
By early spring, the engineering company's list of recommendations for slurry-seal application is undergoing review by city and county governments.
When they're done, Lumos staff will prepare the bid documents that will be distributed to potential contractors. Two contracts go out: One to handle the crack-sealing and patching that precedes the application of slurry, the other for the slurry-seal application itself.
But before the program can begin, Schricker and the Lumos staff choreograph the complexities of closing down streets for maintenance.
The weather plays a factor. The temperature needs to be at least 50 degrees when work starts, and a slight breeze often is helpful. If rain or freezing temperatures are in the forecast within 24 hours, work needs to stop.
Generally, streets are closed to traffic for several hours to while slurry seal is applied and cures. Schools, fire departments, REMSA and Waste Management all may have input on the way that closures are scheduled.
And during major special events such as Hot August Nights, work is stopped entirely.
Gibson says RTC believes the slurry-seal program has been a key element in the steadily improving quality of the region's roads. A recent study found that 88 percent of the roads overseen by RTC are in good condition, which compares with 72 percent in the Bay Area. Only 0.3 percent of RTC roads were described as "very poor."
But that requires near constant vigilance, says Schricker.
"I'm looking at roads non-stop," he says.