Reclaimed Asphalt is asphalt paving that has been removed from roadways and milled or crushed into fine particles which can be added to virgin asphalt cement to create new Hot Mix Asphalt. The use of Reclaimed Asphalt Paving (RAP) improves the economics of roadways by reducing the amount of asphalt binder, aggregate, and mineral filler needed to make new Hot Mix Asphalt (HMA), while simultaneously eliminating the need to landfill waste demolition materials, making it both a cost-effective and environmentally responsible solution.
Reclaimed asphalt is typically a filled asphalt containing bituminous binder blended with solids including aggregate and rubber, and these solids result in very high densities and viscosities, as well as an abrasive nature that creates the need for extra clearances, low run speeds, and the inclusion of hardened parts. To properly handle these materials, iron or steel positive displacement pumps with electric heat or jacketing for steam or hot oil heating are necessary to maintain the material at the temperatures required to liquify the asphalt binder, which can reach up to 300°F (149°C).
Milled, fine-screened RAP may be conveyed cold to mix with hot aggregate from the drum dryer to be blended with asphalt binder in the pugmill. Viking pumps are used in the binder feeder system to meter hot asphalt cement and recycling agent from storage tanks to the pugmill. Hot In-Place Recycling of the top layer of asphalt pavement involves heater scarification remixing and repaving in one continuous operation, eliminating the need to transport RAP to a hot mix plant. These use Viking pumps to meter the rejuvenator oil onto milled pavement mixed in place.