Nimitz Gets a Facelift with Scrap Tires
By Corey Lyons
Contra Costa Newspapers
July 7, 2001
OAKLAND -- A massive paver machine, its lights cutting through a layer of haze, rumbles along a stretch of freeway once punched full of potholes.
With an ear-splitting hiss, the machine dumps a fresh layer of black goo, a sticky substance mixed with ground scrap tires.
The nasty Nimitz is getting a facelift.
Construction crews are laying rubberized asphalt on a 25-mile stretch of Interstate 880, part of a major rehabilitation project on the East Bay's busiest freeway.
Workers began the $45 million job about three weeks ago. They are not expected to finish until late next summer because of heavy traffic flow.
Some lanes are being closed every night on weekdays as workers spread a 2-inch coat of smoldering rubber -- followed by an inch of spongy asphalt -- over the existing road.
The new surface, which melds ground-up tire rubber with tar and oil, promises to last longer and absorb sound better than its old, cracking counterpart.
Even better, transportation officials say, the project will gobble up more than 400,000 scrap tires.
"You've got 90 percent of your tire that will never be used after you wear out the edges. What do you do with it?" asked Saeed Shahmirzai, Caltrans' repaving manager for the Nimitz project.
In this case, it gets ground up into shredded crumbs and added to an asphalt paving mix. Caltrans has used recycled tire rubber in more than 200 rehab projects, diverting more than 2 million tires from landfills and illegal dumps.
Rubberized asphalt, which is becoming increasingly popular nationwide, is being used on an experimental basis in parts of the Bay Area.
But the Nimitz project is among the largest of its kind in California.
On a recent night under a thumbnail moon, contractors poured a black coat of asphalt in the fast lane of southbound I-880 near Network Associates Coliseum. An orange paver machine, traveling about 3 mph, unloaded the grainy substance over the road. A pair of smaller trucks, or "rollers," followed behind to eliminate flaws.
"They have to follow to get the wrinkles out. Because no matter how many times he goes over it, he leaves some marks," said Shahmirzai, pointing to a curdled crease of goo.
The repaving, which stretches from Mission Boulevard in Fremont to High Street in Oakland, includes construction firms working at opposite ends of the Nimitz.
The goal for each contractor is to repave a mile of one lane each night. A 24-truck fleet will dump 1,000 tons of rubberized asphalt in about 4 1/2 hours.
Crushed by big rigs and pummeled daily by East Bay motorists speeding toward Silicon Valley, I-880 has suffered a severe beating during the past two decades.
While mulling over the surfacing job along the bumpy freeway, Caltrans engineers scrutinized every crack and crater.
Arun Bhatnadgar, a transportation engineer, walked up and down the south end of the freeway project long before any work began. "I walked for two months," he said. "By the time I got home, I was a vegetable."
Any crack that measured larger than a quarter-inch was dug out and repatched. The remaining splits were filled with liquid asphalt, creating a flat surface on which to begin laying rubber.
Recycling alone makes the project difficult to criticize. According to the Asphalt-Rubber Technology Center, there are approximately 270 million waste tires generated each year in the United States -- or nearly one for every person in the country.
Most states, including California, do not allow whole scrap tires to be pitched into landfills. Whole tires do not stay buried for long.
And once they surface, they become major fire hazards and breeding grounds for mosquitoes. Last year, Caltrans used about 1.2 million used tires for its rehabilitation assignments.
Still, workers on the Nimitz often feel the wrath of angry motorists.
Some drivers roar by in the wee hours of the morning, hurling insults, objects and one-finger salutes.
"I've worked on a lot of freeways, and 880 is different it seems like everybody is angry," said Shahmirzai, 40, a Caltrans project manager since 1991.
Because of high traffic volume, contractors are limited to working late at night. And with an hour to set up and an hour to shut down, the window in which to work shrinks to about five hours. The crew also will likely shut down in late October when the mercury drops too low for asphalt to stick.
"I can just shut down the freeway on Sundays and finish in 10 weeks," Shahmirzai said. "But we can't take away that convenience."
Contra Costa Newspapers
July 7, 2001
OAKLAND -- A massive paver machine, its lights cutting through a layer of haze, rumbles along a stretch of freeway once punched full of potholes.
With an ear-splitting hiss, the machine dumps a fresh layer of black goo, a sticky substance mixed with ground scrap tires.
The nasty Nimitz is getting a facelift.
Construction crews are laying rubberized asphalt on a 25-mile stretch of Interstate 880, part of a major rehabilitation project on the East Bay's busiest freeway.
Workers began the $45 million job about three weeks ago. They are not expected to finish until late next summer because of heavy traffic flow.
Some lanes are being closed every night on weekdays as workers spread a 2-inch coat of smoldering rubber -- followed by an inch of spongy asphalt -- over the existing road.
The new surface, which melds ground-up tire rubber with tar and oil, promises to last longer and absorb sound better than its old, cracking counterpart.
Even better, transportation officials say, the project will gobble up more than 400,000 scrap tires.
"You've got 90 percent of your tire that will never be used after you wear out the edges. What do you do with it?" asked Saeed Shahmirzai, Caltrans' repaving manager for the Nimitz project.
In this case, it gets ground up into shredded crumbs and added to an asphalt paving mix. Caltrans has used recycled tire rubber in more than 200 rehab projects, diverting more than 2 million tires from landfills and illegal dumps.
Rubberized asphalt, which is becoming increasingly popular nationwide, is being used on an experimental basis in parts of the Bay Area.
But the Nimitz project is among the largest of its kind in California.
On a recent night under a thumbnail moon, contractors poured a black coat of asphalt in the fast lane of southbound I-880 near Network Associates Coliseum. An orange paver machine, traveling about 3 mph, unloaded the grainy substance over the road. A pair of smaller trucks, or "rollers," followed behind to eliminate flaws.
"They have to follow to get the wrinkles out. Because no matter how many times he goes over it, he leaves some marks," said Shahmirzai, pointing to a curdled crease of goo.
The repaving, which stretches from Mission Boulevard in Fremont to High Street in Oakland, includes construction firms working at opposite ends of the Nimitz.
The goal for each contractor is to repave a mile of one lane each night. A 24-truck fleet will dump 1,000 tons of rubberized asphalt in about 4 1/2 hours.
Crushed by big rigs and pummeled daily by East Bay motorists speeding toward Silicon Valley, I-880 has suffered a severe beating during the past two decades.
While mulling over the surfacing job along the bumpy freeway, Caltrans engineers scrutinized every crack and crater.
Arun Bhatnadgar, a transportation engineer, walked up and down the south end of the freeway project long before any work began. "I walked for two months," he said. "By the time I got home, I was a vegetable."
Any crack that measured larger than a quarter-inch was dug out and repatched. The remaining splits were filled with liquid asphalt, creating a flat surface on which to begin laying rubber.
Recycling alone makes the project difficult to criticize. According to the Asphalt-Rubber Technology Center, there are approximately 270 million waste tires generated each year in the United States -- or nearly one for every person in the country.
Most states, including California, do not allow whole scrap tires to be pitched into landfills. Whole tires do not stay buried for long.
And once they surface, they become major fire hazards and breeding grounds for mosquitoes. Last year, Caltrans used about 1.2 million used tires for its rehabilitation assignments.
Still, workers on the Nimitz often feel the wrath of angry motorists.
Some drivers roar by in the wee hours of the morning, hurling insults, objects and one-finger salutes.
"I've worked on a lot of freeways, and 880 is different it seems like everybody is angry," said Shahmirzai, 40, a Caltrans project manager since 1991.
Because of high traffic volume, contractors are limited to working late at night. And with an hour to set up and an hour to shut down, the window in which to work shrinks to about five hours. The crew also will likely shut down in late October when the mercury drops too low for asphalt to stick.
"I can just shut down the freeway on Sundays and finish in 10 weeks," Shahmirzai said. "But we can't take away that convenience."
posted by Corey at 10:30 AM
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