Greenbuild 2008: New Pavements Have Green Tint

Two of the four key trends in paved surfaces are helping the cause of concrete and asphalt recyclers, according to a presenter at the Greenbuild International Conference and Expo.

At a session entitled “Greening the Blacktop,” Meg Calkins of Ball State University, Muncie, Ind., noted that in addition to seeking pavements with increased performance and longer life, buyers are requesting pavements that offer reduced environmental impact and the use of recycled materials.

Speaking to a room with several hundred attendees, with architects and civil engineers heavily represented, Calkins gave an overview of the use of asphalt rubber, fly ash as a pavement ingredient and recycled concrete and asphalt in parking lots and other applications.

Calkins noted that rubberized asphalt can contain up to 15 or even 22 percent processed tires as an ingredient, while recycled asphalt pavement (RAP) can contain a much higher 30 to 50 percent recycled content.

Currently, both asphalt and concrete are far more commonly recycled than not, making recycled aggregates commonly available in most regional markets. Recycled concrete is most commonly used as a base course material, although Calkins said 11 states have specifications that allow it to be used as an aggregate in paved surfaces in highway applications.

Presenter Jason Dunster of Walker Parking Consultants, Chicago, listed a variety of green building considerations from which building owners, architects and engineers can select.

In addition to using recycled aggregates, Dunster mentioned RFID systems for frequent parkers to prevent engine idling; preferred parking for hybrid vehicles; solar or photovoltaic panels to produce energy; and bins for the storage and collection of recyclables.

Steffen Turoff, also of Walker Parking Consultants, remarked that specifiers of many LEED (Leadership in Energy and Environmental Design) projects are considering providing fewer parking spaces in favor of convenient public transportation access; bicycle storage areas and showering facilities for bicyclists; and subsidies for employees who use public transportation or other alternative means of transportation.  

The Greenbuild International Conference and Expo took place Nov. 18-21 in Boston.