The finished product is a combination of a PASS CR scrub seal, which acts as a stress-absorbing membrane, and a micro-surface placed on top. Photo: Santa Barbara County Public Works, Transportation Division
PASS CR is being applied and scrubbed into the road surface with a scrub broom that is specifically designed for this process. Photo: Santa Barbara County Public Works, Transportation Division
Surface treatment sticks
Emulsion saves county dollars—and makes sense.
As part of its pavement preservation program, Santa Barbara County selected a rejuvenating fog seal called PASS QB, a polymer-modified emulsion made by Dana Point, Calif.-based Western Emulsions Inc. “PASS QB was not the first product we tried over the years, but it's the first product that has performed up to our expectations,” says Kevin Donnelly, project manager for the county's transportation division.
Most importantly, the county saves approximately 80% of the cost of a slurry seal by performing the fog seal. This approach has allowed for the reallocation of dollars to roadways requiring major rehabilitation. More than two-thirds of the county's roadways are now in the pavement preservation mode, up from 45% in 1999.
The county always is exploring technologies that provide lower cost options to balance ever-escalating oil and paving costs. It initiated a PASS Scrub Seal with a Micro-Surfacing Cap project in 2005 on a series of deteriorated roadways. At $4.62 per square yard, cost savings were realized on roadways that otherwise would have received an overlay at $18 per square yard, pavement recycling at $50 per square yard, or complete reconstruction at $75 per square yard. The total cost of the project was $1 million, paid for by a sales tax approved by voters in 1989.
“In the early 1990s, Santa Barbara County had a chip seal project that didn't go as planned, which scared us out of doing chip seals,” says Scott McGolpin, deputy public works director for the county. “But the performance of the PASS material convinced us to try another chip seal test. It was a tremendous success, and saved the county 75% of the cost of a pavement overlay. Best of all, residents on those streets who were waiting for years for an overlay were very satisfied with the results.
“We also realized that the PASS product saves time and money because our crews don't need to crack-seal in advance of the chip seal application. PASS is designed to seal those cracks at the same time,” says McGolpin. Within two months, the agency repaired approximately 217,000 square yards of deteriorated roadways.