February 26, 2010

FEATURE | Roadbuilding

Get hip to Reclaimed Ashpalt Pavement, roadbuilders urged

IAN HARVEY

correspondent

Roadbuilders and owners need to sing from the same song sheet about RAP, attendees at the Ontario Hot Mix Producers Association’s annual seminar heard.

Engineer Sandy Brown, technical director of the OHMPA continued his longstanding passionate plea for members to get hip about RAP — Reclaimed Asphalt Pavement — and to shout out to their customers, noting the material has been around for decades but just isn’t getting the respect it should.

“Twenty years ago we had similar issues, that quarries five kilometers down the road were running out of material — today it’s 200 km away,” he said.

“Oil prices were going up then, too. Even the provincial government’s own environmental commission says they’re not using enough recycled materials.”

Roads are 95 per cent aggregate stone and five per cent asphalt cement and both can be recycled and reused. RAP is obtained when pavement is milled or excavated. With higher oil prices and political resistance to new quarries, it’s becoming more efficient to stockpile it in yards and then crush it seasonally to make it available for peak road construction season. Higher tipping fees at landfills have also been driving the switch.

Pulverizing in place is also fast growing in popularity, Brown said later, adding the trend in the U.S. is to use more RAP with it rising to 85 per of all projects from 75 per in the last survey a few years ago.

“In the GTA 100 per cent of all RAP, from milling or excavation is used but in other areas they don’t use it and they don’t have plants because it’s expensive to set up and they have to have continuous supply or it is no economical,” he said in an interview.

He said roads are almost never wholly replaced and that unless it need to be moved or reconfigured for new sight lines, only the top layers are excavated. It makes sense to then return that mix to the road, since it’s already in the right consistency.

“On average, about 15 per cent of RAP is not used across Ontario,” he said.

“And that ends up being used on the shoulder and other places — none of it goes to landfill. You can’t do that with concrete road, you can break them up and use them as aggregate, but so far they haven’t been successful in reusing it as concrete again, though there are a couple of studies underway.”

He said Ministry of Transport Ontario OPSS.PROV 1151 specifications now allow up to 40 per cent RAP in the mix depending on the applications, but municipalities are still reluctant to use that level.

“We need to talk to them and each one of you to talk to your customers,” he said. “We have to educate them because a lot of municipalities don’t use any RAP at all. Many of these folks at the municipalities have never been to an asphalt plant, so you should invite them out, to show them we can do it properly and produce a quality product.”

He said it make sense on all levels, from an environmental, economic perspective and finished product perspective.

“The City of Edmonton talks about mining their roads for mix,” he said. “They have to, because their nearest quarry is 180 km away.”

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