Hot, Cold and Green

(and the 3Es)

In-place pavement recycling meets a variety of needs.

By Tom Kuennen, Contributing Editor

Green construction now is the No. 1 theme in roadbuilding, and hot-in-place pavement recycling (HIR) and cold-in-place pavement recycling (CIR) have taken on the “green” mantle big-time as the industry positions itself to new customers.

In tight quarters in the Pacific Northwest, a cold-in-place recycling train of Valentine Surfacing climbs a mountain grade.

While reuse of materials and fuel savings always have been major sales themes of HIR and CIR recycling, the environmental benefit of these two processes has waxed large as green construction rises in desirability among road agencies.

In the regions where HIR and CIR specialty contractors operate, in-place recycling has been recognized as an environmentally sound road reconstruction application by the American Association of State Highway and Transportation Officials, via AASHTO’s Center for Environmental Excellence (http://www.environment.transportation.org/).

In-place recycling, both hot and cold, is likewise encouraged by the Federal Highway Administration (FHWA) as it implements its environmental stewardship policy.

In Kansas, a Mobile Asphalt Resurfacing System of Dustrol Inc. hot-in-place recycles U.S. 75.

In-place recycling (instead of conventional hot-mix asphalt paving) now is being encouraged in regions where air quality is an issue. For example, in 2011, California’s wine country agencies of the City of Napa and County of Sonoma are teaming up to promote cold-in-place recycling technology as a means to reduce carbon emissions. And the in-place recycling contractors are putting money down to support this interest.

Late last year, the national association that represents HIR and CIR specialty contractors among others – the Asphalt Recycling & Reclaiming Association – launched a new research center for asphalt recycling technologies. The Pavement Recycling and Reclaiming Center (PR2C) opened Oct. 1 and is a partnership between ARRA, California State Polytechnic University (Cal Poly) and the state Caltrans agency.

Feds Boost HIR, CIR Recycling

HIR and CIR processes are among the road reconstruction methods encouraged by the Federal Highway Administration as being exemplary green roadbuilding processes. This follows FHWA’s policy of encouraging recycling and use of recycled materials wherever possible in roadwork (http://www.fhwa.dot.gov/legsregs/directives/policy/recmatpolicy.htm).

“In-place recycling is another technology that we are promoting very heavily within federal highways in conjunction with our partner around the country, ARRA,” says Steve Mueller, P.E., pavement and materials engineer, Federal Highway Administration Resource Center, Lakewood, Colo. “There is cold-in-place recycling, and hot-in-place recycling, as well as full-depth recycling, so there is a lot more that we can do [to recycle building materials] with the material right on the road, instead of having to bring in new materials.

“We issued our recycling policy in 2002 with six key points,” Mueller said last year during a National Highway Institute webinar on Recycled Material in Highway Construction. “First, recycled and reused materials are viable resources. Many times, the best materials are those already out on the road. Our policy says that recycled materials should get first consideration when we are looking at building new roads or preserving existing roads. We want to consider use of recycled materials early in the planning and design process. If we can use recycled materials, we should.

“The economic benefits should be considered in the material selection process; the economics need to be good in order to use recycled materials,” Mueller added. “Restriction on the use of materials should be technically based. If you are saying you cannot use recycled materials in pavements, you should have a good reason why not. There are still jurisdictions that completely prohibit the reuse of certain recycled materials and we need a technical foundation for that. Lastly, the material should not adversely impact the environment and should perform as intended.”