ROANOKE TIMES
Copyright (c) 1997, Roanoke Times
DATE: Saturday, April 12, 1997 TAG: 9704140063
SECTION: VIRGINIA PAGE: C-5 EDITION: METRO
Zehren is a sales manager for George Fischer Disa Goff Inc., a maker of highway construction equipment in Oklahoma City. One of his machines might hold the answer to Williamsburg's recurring public works puzzle: How to make new asphalt look brown.
City officials say they are willing to entertain just about any suggestion to maintain the colonial look.
Zehren's machine, called a shotblaster, works like a giant machine gun combined with a vacuum cleaner. Millions of steel pellets about the size of sand are shot into the pavement, then sucked back into the machine.
Normally, the million-dollar contraption is used on concrete to create better traction or restore whiteness. If the machine picks up tar, the theory goes, brown pebbles in the asphalt will be exposed instantly, instead of gradually due to erosion.
Even Zehren has his doubts. Because tar is gooey, he said, steel pellets may stick to it, or the whole mess may clog the machine's filters.
``It's just an idea,'' City Engineer Steve Martin said.
Streets at Colonial Williamsburg have long been spread with a tar-like binder, then covered with brown pebbles gathered from the bed of the James River.
As months passed, pebbles have been dislodged by carriages and horseshoes. Loose pebbles became a hazard for pedestrians, and city workers had to periodically clean the tiny stones from street drains.
The Colonial Williamsburg Foundation last used the pebble approach in 1993 and has worked with the city to study other methods.
The formula is slightly different for other city streets. There, roads are paved with asphalt that contains brown pebbles. But the effect is delayed because of tar in the mixture.
Three years may be too long to wait. Williamsburg planning commissioners recently asked for brown pavement on a driveway surrounding a planned village green in the redeveloped Northington Block.
Shotblasting may be a solution, said Carlton Abbott, the architect on the project. ``This is new technology in some respects,'' Abbott said. But he cautioned, ``We're very careful to recommend only methods that are tried and true.''
Abbott has other ideas he admits probably will not fly, including power-washing the new road and catching petroleum-laden waste with bales of hay, which could be taken to a toxic waste facility.
Shotblasting is sometimes used on ship decks, said Zehren.
Its applications on concrete are well known, said Bob Milliron of Lanford Bros. Inc., a Roanoke highway-repair contractor that uses the machine to create a rougher surface on bridges.
In France, contractors use shotblasting equipment on limestone roads to reduce the risk of skidding, Milliron said. ``But it's only a temporary fix because the limestone will polish again.''
Shotblasting's efficiency in creating brown streets is untested. It would probably work on asphalt only in winter, if at all, Milliron said; by then the pavement might be brittle enough, even with the heat of the machine.
If a solution exists, Abbott said, count on engineers to find it. Thanks to them, he said, modern streets beat the dirt roads that used to cross the city, no matter what color. over the years,'' Abbott said.
LENGTH: Medium: 77 lines ILLUSTRATION: PHOTO: ASSOCIATED PRESS. There are a lot of ideas out there -by CNBsome of them wild - for retaining the flavor of Colonial
Williamsburg's light brown streets.
|By MARC HELLER| |THE DAILY PRESS|
WILLIAMSBURG
When your image relies on brown pebbles from the bed of the James
River, and modern technology builds pavement with black tar, what to
do?
David Zehren didn't notice the color of the streets on his last
visit to Williamsburg. But he might play a role in preserving their
light-brown shade.