Cost-Effectiveness Determines Material Used on Roads
The Daily Herald continues its weekly report featuring answers to your questions about traffic problems and road construction.
Q. I have a general question on road building that I see in our area. Sometimes I see roads built with pure concrete and no blacktop and sometimes I see roads repaired with concrete and blacktop. My question is what is the difference? Is the blacktop just for residential areas or does it have to do with a heavier truck load?
- J.R., Elk Grove Village
A. The decision whether or not to use asphalt with concrete is based on a number of issues, Illinois Department of Transportation officials say.
Truck traffic can be a factor, but so can economics.
For instance, concrete "becomes more cost-effective on a larger job," said Mark Reznicek, who is in charge of pavement designs for IDOT.
Also, concrete is preferable for roadways with a high rate of truck traffic because it's sturdier, Reznicek said.
"Bituminous (another name for asphalt) tends to rut when you have heavier traffic," Reznicek said.
Asphalt will usually be poured over concrete "when it's served its life and you have a lot of cracking typically 20 years later."
Because of the heavy volume of truck traffic in the Chicago area, IDOT usually pours asphalt over ailing concrete. But elsewhere in the state where there is less truck traffic, IDOT will lay concrete over concrete because it is less expensive, Reznicek said.
IDOT began in the road business in the 1920s, when the agency inherited all of the state's concrete roads, said Les Aling, a maintenance operations engineer for IDOT.
"Ever since then we've usually built concrete roads," Aling said.
Q. I have a question about traffic overflow from a main street onto a residential street here in Arlington Heights. I live on the 1700 block of Windsor Drive - the section of Windsor south of Palatine Road that used to connect to Rand Road but does not anymore. It has basically become the huge morning and evening fast track around the Palatine/Rand Road intersection. …