LEAP Fills a Void Commonly Occupied by Piles of Waste Environmentally Friendly Process Uses 100% Recycled Asphalt By LEAP
T
here is room for improvement within the paving community when it comes to being environmentally friendly. Did you know that for each ton of virgin asphalt produced, there is a quarter-ton of waste recycled asphalt pavement (RAP)? Fortunately today, there is an industry leader in the area of sustainability, using a patented design and process to convert 100 percent RAP into high-performance hot mix asphalt. Better yet, an independent third party confirms that it is stronger, tougher and longer-lasting than conventional asphalt. The LEAP technology breakthrough happened in the spring of 2012; shortly thereafter, the Brooklyn Park-based company opened up the paving industry to year-round production of its Hot Mix Asphalt (HMA). Sustainability is at the forefront because the LEAP production process uses little energy, is environmentally friendly and creates next to zero greenhouse gas emissions. Instead of waste piles for disposal everywhere, LEAP’s process heats the RAP mix to temperatures necessary to meet performance requirements; and the HMA produced using the LEAP process meets or exceeds minimum performance standards (including trucking security requirement specifications for most states) when using 100 percent RAP. LEAP is currently producing two different types of mix designs, and both are suitable for road or parking lot paving and new construction.
How did LEAP do it? There are other companies around the globe working to produce high RAP mix designs, but it’s not simple or easy. The LEAP discovery isn’t the heating method alone, but a combination of several unique processes that work in concert providing the ability to utilize 100% RAP mix designs to create a high-performance product. LEAP utilizes an advanced microwave heating system, not the kind you would typically find in your home kitchen. This system, known by LEAP as the Low Energy Heating System (LEHS), uses the microwave energy to selectively heat the aggregate within the I-RAP. Because microwave technology is used instead of open flame, no pollution is created during production.
How can it be stronger and better? Here, the story gets technical: Virgin asphalt has two primary chemical components — asphaltenes and maltenes. Asphaltenes are hard materials that provide the mechanical strength while maltenes provide the oily fraction that functions as the sticky component in HMA. Maltenes oxidize with age or excess heat to form asphaltenes, which causes the HMA to become hard and brittle. The aged or 10
Minnesota Communit y Living
heat damaged HMA cracks under heavy loads, causing failures of the road surface. LEAP’s handling and treatment of the RAP prior to injection along with the emulsion formulation used in the injection defines the final results of performance. The microwave heating allows the new emulsion to bond with the old asphalt cement, creating what we call a fused surface material. LEAP plants have a smaller footprint than conventional asphalt plants. LEAP processes the RAP into I-RAP (injected/stabilized recycled asphalt pavement) which is kept at ambient temperature in storage until heating. On demand the I-RAP is loaded into feed hoppers and conveyed through LEAP’s LEHS (Low Energy Heating System) unit. The production room is a clean room with advanced digital control features. After heating, the material is conveyed to a storage silo and ready for contractor pick-up, similar to conventional asphalt plants. The simplicity of the plant design and ease of operation allows for 12 month production in any climate.