Industry Insight: Another man’s trash

Green initiatives, project costs spur construction waste recycling

Although they have not stood out historically as leaders of green building practices, the demolition and paving trades are finding new business opportunities and a new environmental mission in recycling construction debris.

“Our goal is to recycle as much as possible from our demolition projects,” said Brandon Bonanno, General Manager of the recently formed Demolition and Material Resources Division of Gray & Son, Inc. “Our question is always what waste streams will we have on the project and could it be recycled to decrease costs.”

Gray & Son branched into demolition and recycling in February 2020 to expand the services offered to its clients and avail of the “very large growth potential” it saw in recycling materials for beneficial reuse in order to lower project costs and help clients reach sustainability goals, Bonanno said. “On public jobs for the state and federal governments, there is often a waste-management mandate so the project may have a goal that 60-80 percent of waste material must be recycled.”

In the first nine months of operation, the division processed in excess of 40,000 tons of demolition aggregate for “beneficial re-use” of the material, as construction site fill.

In addition to lowering the need for virgin materials and the expense of hauling debris to a landfill, the recycling, crushing and re-use process can all happen on the same site (space permitting) and eliminate the need to truck materials from site to site.

Gray & Son recycles a variety of materials from demolition waste, including steel and wood, on-site and has a network of subcontractors for off-site recycling of materials. Even seemingly worthless material, such as torn down wallboard and other demolition wastes, can be processed at a recycling facility into a soil-like substance that is used as daily cover for landfills.

Technology advances, such as cleaner engines in crushing equipment and internal spray bars to suppress dust, help lower the environmental impact of crushing and recycling, he added.

Maryland Paving, a division of Gray & Son, has been recycling asphalt for decades. But that operation is also now expanding.

On average, paving projects in Maryland include 25-30 percent recycled asphalt product (RAP). “But in the industry, there is actually some work that uses 100 percent recycled asphalt to create new surfaces,” said Jeff Graf, Senior Vice President of Asphalt Operations. “There are recycling agents and different types of asphalt cement that you can add to RAP to basically bring it back to life.”

Furthermore, asphalt that includes RAP can be designed to meet most of the specifications of completely new asphalt.

“Right now, we are leaning towards performance-based specifications so there are multiple things we can do to the RAP to get the same performance values as the virgin mix,” Graf said.

In addition to diverting materials away from landfills and lowering the need to harvest new resources, RAP delivers one added environmental benefit, he said.

“Generally speaking, you would have to super heat the virgin aggregate,” Graf said. “But when recycled material is being incorporated into products, we soften the recycled asphalt and we use recycling agents so we don’t need to run the temperatures nearly as high. We don’t need nearly as much heat energy in our plant and we don’t create what we call blue smoke – the emissions that come off of super heating the aggregate and the asphalt oil. We become more environmentally friendly by using warm mixing agents and higher percentages of recycled pavement.”