Why aren't all our streets paved in concrete?

? Whitetop works on the test stretch of Marion Street, but not every street is eligible, so 'superpave' asphalt remains the surface of choice.

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By KEN TRAINOR

You may have noticed something different about driving north on Marion Street from Ontario Street to Chicago Avenue the last three years. It's whiter than the average street. It's smooth, feels more solid, doesn't show the same cracking and isn't so susceptible to potholes. In fact, there aren't any potholes at all. Strange.

It might also grab your attention because of the soft flapping of tires over the seams every five feet that allow for the street's expansion and contraction.

It's test pavement, and the test has been ongoing since the steel-reinforced "whitetop" concrete was poured in 2001. We thought we'd find out how the test is going.

"We're very satisfied with its performance," said Village Engineer Jim Budrick.

So why doesn't the village use it on every street? Well, it probably won't surprise you to hear that when it comes to paving streets, especially in Oak Park, it's never that simple.

Granted, this material beats the traditional "blacktop" asphalt, a collection of small stones and oily tar binder that seems to commence cracking and crevicing the instant it dries. The village makes an effort to fill the cracks when they occur with "joint sealer," but Budrick admits, "It's a daunting task." Too many miles of streets, too many cracks, not enough street workers. Realistically, there's no way to keep up with it.

Asphalt has improved though, Budrick said. About five years ago, manufacturers started adding polymers to create a new mixture dubbed "Superpave."

But the cracking isn't due to the mealiness of the product, Budrick said. It's "reflective" cracking, meaning it comes from below where the pavement is laid over an irregular base surface, rendered uneven by the many layers applied since the first stone base was laid?#34;for most streets in Oak Park?#34;in the 1930s. Once the cracks appear and water starts to work on them, all hell (or in this case asphalt) breaks loose. The increasingly ineffective attempts to patch it create the topography of tiny mounds and ragged depressions so familiar to village drivers.

Even more frustrating, almost immediately after a street is repaved, it seems, a small army of predators from the various utilities attacks and starts digging up the newly paved street to make repairs on underground lines, then filling the holes with uneven mounds of asphalt that make some streets resemble ancient burial grounds. The average utility system in Oak Park is over 70 years old, Budrick said. The constant excavating aggravated him more when he first started with the village 26 years ago, "but I've gotten used to it," he said.

Budrick added that quality control on the fill-ins is an issue, but they have a record of every patch and make the utilities come back if they don't do it right. Still, Oak Park doesn't have jurisdiction over state routes like Harlem Avenue, where IDOT appears to be less diligent in their monitoring?#34;as evidenced by the patchwork chaos that has returned a newly paved surface in many places to its pre-paved unevenness (drive north on Harlem in the right-hand lane from Chicago to Augusta for a harrowing example). Utility excavations would also be necessary with concrete streets, of course, and when that occurs, a less durable kind of concrete is used for the fill-in.

So why is asphalt used more than the more durable concrete? Budrick said the village would like to use it elsewhere even though one block of asphalt (grinding down, resurfacing, curb work, etc.) cost $65,000 (2001 figure) vs. $77,000 per block for the fiber-reinforced concrete overlay. Some of that cost differential is offset by durability (15-17 years for asphalt as opposed to 20 for concrete), but the main problem, Budrick said, is that few of the higher-volume-traffic streets (the only ones considered) are deep enough to accommodate the four inches of concrete required (the village takes core samples to determine this).

A couple of promising "collector" streets are due for repaving in the next five years, however, Budrick said, specifically Jackson and Augusta boulevards, and those may qualify for the concrete treatment.

The good news is that all alleys are eligible for concrete overlays since that's the way they were built in the first place.

Next year Madison is scheduled to be repaved (asphalt alas), along with a stretch of North Avenue (Narragansett to Austin in partnership with Chicago), but by 2006 all the major streets in town will be done. More money will then be freed up to improve the local streets, Budrick said.

"There has been an increased pavement investment," he said. "We don't get as many complaints as we used to."


 

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