Archive for Tuesday, March 8, 1994


March 8, 1994


A new pavement material stops vehicles faster and prevents street deterioration, Lawrence city officials say.

It's bumpy. It's gritty. It makes some drivers wonder if a tire is suddenly going flat.

"It" is Ral-umac, a road surfacing material developed in Germany and being tested in two Lawrence locations.

After nearly six months at two test sites on Sixth Street at Kasold Drive and Lawrence Avenue, the material seems to be holding up well, city officials said.

"What I've been looking for are sympathy cracks, cracks in the original surface that will show through," said George Williams, Lawrence's public works director. "A lot of times, if you put on an overlay, sometimes cracks on the original surface will show up."

Cracks give water a point of entry beneath pavement, which can lead to road deterioration and eventually potholes and other signs of pavement failure.

But so far the German road material appears crack-free, Williams said.

The pavement at the test sites seems safer for drivers, in part because the material is skid resistant, said Tom Orzulak, the city's assistant director of public works.

"It has a nice rough texture. Those intersections tended to be slick, especially when it's icy," he said.

Because this winter has been relatively mild the new road material has not been subjected to frequent snowplow scrapings and has not been tested thoroughly, Orzulak said.

The new material also seems to prevent the rutting that occurs in asphalt when tire tracks beat a path into the lanes. When water collects in the ruts, the likelihood of hydroplaning or a skid increases.

The material also seems to prevent other minor indentations in the pavement, such as shoving, Williams said.

"The intersection of 15th and Iowa is a good example of shoving," he said. "That happens when trucks put on their brakes and kind of bounce to a stop. It produces that washboard effect in the pavement."

The material has "a textured surface, more like a chip seal, a country road-kind of surface," Williams said. "In some places where you have steep banked curves, it is used as a skid-resistant material."

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