Logan to test greener, longer lasting asphalt

By Nicole C. Wong, Globe Staff

This fall, Logan International Airport will become the first in the country to pave a runway with asphalt that's produced and poured in an environmentally friendly way.

The Massachusetts Port Authority yesterday said it will spend $6.3 million to repave portions of a runway with an asphalt mix that contains wax pellets and can be produced at lower temperatures than the 300 degrees required for traditional asphalt.

That means the asphalt uses 20 percent less energy during production and emits 20 percent fewer greenhouse gases during application.

Also, Massport can use a higher percentage of recycled asphalt - up to 20 percent - in the mix. The asphalt cools and cures quicker, too, meaning the runway will be out of service for less time.

Massport officials also predict the new mix will last twice as long under Boston's weather conditions as traditional asphalt, so runways will need less frequent repaving.

"For us in the Northeast, with the snow and ice in the winter and high temperature in the summer, the mix they provide doesn't work here," said Sam Sleinam, Massport's director of capital programs and environmental affairs. "After five years, you start seeing cracks."

Andrea Kvasnak, lead researcher at the National Center for Asphalt Technology at Auburn University in Alabama, said the asphalt mix is too new to bear out Massport's prediction that it will last 10 years. "All of our mixes in the United States are two years old, so we don't know for sure," Kvasnak said.

Massport will apply the new mix to the outer 37.5 feet of each side of 150-foot wide Runway 22L. If it performs as well as the traditional mix, Massport will use it to repave all of another runway.

In the past few years, this asphalt mix has been used on highways, parking lots, and racetracks. But airfields require special formulas and processes because the pavements bear much heavier loads. Once too expensive to use in the United States because of the costs of the additives, the wax mixes have become more attractive as oil prices have soared.

Nicole C. Wong can be reached at nwong@globe.com.