SANFORD — In an effort to take care of what they already have, Sanford Public Works officials will be implementing a different sort of pavement on three city streets.

They’ll be chip sealing – using thermally cured, modified crumb rubber and asphalt base laid over with clean half-inch stone coated with the mixture, which is then rolled onto the roadbed. It’s slated to be used on Milton Avenue, a portion of Brook Street, and on Rankin Street in Springvale village.

The streets were selected because they were just beyond the point where crack sealing will continue to be effective, according to Public Works Director Matt Hill.

The work will likely take place in May or June, said Shawn Bennett of Allstates Materials Group of Windham, the company that will be providing the product and doing the work.

Residents of the streets selected for chip sealing are invited to a series of open houses at Sanford Public Works, 56 School St., each running from 11 a.m. to 1 p.m. The open house for Brook Street is Thursday; Milton Avenue, Friday; and Rankin Street, Monday.

While chip sealing is new to Sanford, it is widely used in other parts of Maine and the northeast. Bennett said the modified rubber type of chip seal was laid down on roads in York in 2015, and that a more common type of chip seal that uses asphalt and water emulsion is common in portions of central Maine.

Bennett estimated that depending on traffic and the condition of the road’s sub-bed, the chip seal can last eight to 14 years.

In 2007, Sanford was spending 85 percent of its road dollars in full reconstruction, at a cost of $1 million a mile, said Hill. With 185 miles of roads, the city would never catch up, he said.

“To deal with this, we’re diversifying the treatment for each specific street,” said Hill. “If we can preserve streets (already) in good shape, we have a strategy going forward.”

The chip seal method costs about $115,000 per mile, while conventional asphalt costs $125,000 to $150,000 a mile, estimated Hill.

According to a story by engineer Dwight Walker in this month’s issue of Asphalt magazine, asphalt binders modified with ground tire rubber have several positive qualities.

“Adding ground tire rubber to asphalt can contribute to improved rutting resistance, skid resistance, ride quality, pavement life and reduced pavement noise levels,” Walker wrote. “Adding rubber to the asphalt liquid retards aging and oxidation of the resulting binder, which increases pavement life by lessening brittleness and cracking. Rubbermodified asphalt binders can be used in open-graded asphalt mixtures, which have reduced hydroplaning, vehicle spray and reduced pavement noise.”

— Senior Staff Writer Tammy Wells can be contacted at 324-4444 (local call in Sanford) or 282-1535, ext. 327 or twells@journaltribune.com.