project management
The RAP bin from Tarmac offers anti-bridging features.
Plan Ahead: Where’s That Recycle Gonna Go?
W
hen the most costly product in an asphalt mix is one that can be created on-site using recycled materials, the savvy producer will find many ways to work with it. Invest in the equipment you need to fractionate your millings, crush to size those chunks of recycled pavement, etc. Fractionating the product makes sense, but have you thought about where the product goes once you have it down to size? Let’s start a discussion of metering and controlling ingredients such as recycled asphalt shingles (RAS) with tips for handling the material. Mitch Duncklee is a software engineer for Systems Equipment in Waukon, Iowa. He suggested producers 20 March 2015
could get more consistent feeding results if recycling operations stayed up to date with their practices. “Pre-processing the shingles differently can make a large difference in how the RAS feeds,” Duncklee said. “While making mix, good feedback control in the blend computer can help smooth out the AC content, but any chance to prevent manic speed changes because of poor feeding should be looked into.” He sees pre-processing as a positive step for future innovations. “Pre-processing and storage would go a long way to make RAS behave like a typical ingredient. It wouldn’t surprise me to see more buildings or shelters to store the more sensitive
By Sandy Lender
materials. A lot of money gets spent removing moisture and clumping in process. Why not eliminate it before it even gets to the bin?” While a recycler will look at pre-processing as sorting the deleterious materials out of the shingle pile prior to grinding shingles to produce RAS, the asphalt plant owner can look at pre-processing at his site as declumping the RAS prior to feeding it into his drum. Preston McIntyre, a sales representative for Rotochopper, once explained that clumping or compacting of RAS usually occurs in one of two ways. “When material is run over by a loader or similar piece of heavy equipment, it compacts,” McIntyre said. “Another clumping