Minnesota Department of Transportation

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Regulated Materials

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Asphalt Sludge

This guidance document is prepared by MnDOT personnel and is intended only for use on MnDOT projects, including partnership projects, and MnDOT Maintenance Operations.

MnDOT has prepared this guidance document to provide its internal procedures and requirements for work performed on MnDOT rights of way, including MnDOT-owned facilities.

This document should not be construed as a full description of all regulations pertaining to the subject matter. Contact the Regulated Materials Unit in the MnDOT Office of Environmental Stewardship for additional information or legal requirements.

Management of Asphalt Sludge

Asphalt Release Agent

Asphalt release agents are applied to equipment to prevent asphalt from sticking to the equipment before handling asphalt. Waste asphalt sludge can be minimized by using an asphalt release product. These products will coat large and small equipment made of metal or rubber. By MnDOT Standard Specifications for Construction, diesel fuel is not allowed for use as a truck bed release or as a release agent for other asphalt equipment/tools.

Approved asphalt release agents are listed on the Approved/Qualified Products, category Asphalt, subcategory Asphalt Release Agents. These products have been approved by the Office of Materials and Road Research and Office of Environmental Stewardship.

The use of an asphalt release product is required instead of diesel fuel because no waste sludge is produced and potential damage to the asphalt mix is limited. Advanced planning should be exercised to prepare the use of the asphalt release agent solution and treating the equipment before handling asphalt. If applied to vehicles or equipment outside, this product should not be used within 100 feet of surface water. During application, reasonable efforts will be made to prevent overspray and dripping on to the ground.

Asphalt Cleaning Agent

It may necessary to clean equipment that has been used to handle asphalt. While diesel fuel cannot be used as a release agent, diesel fuel may be used to clean equipment, such as when removing asphalt from shovels, “tack” trucks, and trailers used by MnDOT maintenance operations. Using diesel fuel can produce an asphalt sludge during the cleaning process that must be captured in container, such as a 5-gallon bucket. The waste asphalt sludge must be managed for disposal because the diesel content does not make it suitable for reuse. When asphalt sludge accumulates it must be separated out from the diesel fuel. The diesel fuel can then be reused for cleaning and the asphalt sludge may be stored in a properly labeled 55-gallon drum until the drum is full and ready for disposal. Previous laboratory analysis of asphalt sludge has demonstrated that the sludge can be managed as a non-hazardous waste.

The following procedure should be used to manage asphalt sludge. Contact the Regulated Materials Unit for assistance regarding management of asphalt sludge, especially if unique circumstances make it difficult to follow the recommended procedure provided below.

General Guidance

Asphalt Sludge

  • Only use diesel fuel when an asphalt cleaning agent is not available. Do not use gasoline or any other solvent as doing so may create a very hazardous environment and may create an additional hazardous waste stream.
  • As when using any chemical, make sure that the proper personal protective equipment (PPE) is being worn, such as nitrile or rubber gloves, goggles and/or a protective face shield and respiratory protection if needed.
  • Ensure there is adequate ventilation and flammable products are not used near open flames.
  • Make sure you and affected employees read and understand the Safety Data Sheet for the product you are using.
  • Separate the diesel fuel from the asphalt sludge. Provide adequate time for separation of diesel fuel and asphalt sludge. The objective is to minimize any liquid diesel being transferred to the sludge storage barrel.
  • The resulting sludge must be placed in an appropriate Federal DOT spec approved drum labeled “Asphalt Sludge”.
  • Keep lids secured and bungs closed on drum at all times, except when waste is being added.
  • When drum is full, mark the fill date on the drum and notify the District Waste Management Coordinator. Move the drum to a designated waste storage area.
  • The diesel fuel can be used over again to clean asphalt from equipment.
  • Contact your District Safety Administrator if there are any unanswered questions regarding chemical usage.

Waste Diesel Fuel

  • If the diesel fuel becomes unusable and becomes a waste, the diesel fuel must be placed in an appropriate Federal DOT spec approved drum labeled “Waste Diesel Fuel”. Waste diesel fuel will be disposed of with MnDOT’s hazardous waste contractor or fuel recycling contractor depending on laboratory results. Contact Regulated Materials Unit personnel to evaluate the flashpoint of the waste diesel to determine appropriate disposal method. Additional sampling and analysis may be required if it is desired to recycle the fuel through the MnDOT approved fuel recycling contractor.
  • Keep lids secured and bungs closed on drum at all times, except when waste is being added.
  • When drum is full, mark the fill date on the drum and notify the district waste management coordinator. Move the drum to a designated waste storage area.