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Tools and Resources for Using Industrial By-Product Materials in Road Construction

November 2008 (revised)

General Information

U.S. EPA's Industrial Materials Recycling (IMR) Program.
Homepage for the Industrial Materials Recycling Program

US EPA's Resource Conservation - Reduce, Reuse, Recycle - Industrial Materials Recycling - Collection of tools and resources as well as state beneficial reuse regulations and new items.

AASHTO Center for Environmental Excellence Waste Management & Recycling Page

User Guidelines for Industrial Byproduct Materials in Pavement Construction
The User Guidelines have long been a key FHWA information resource for 20 different byproduct materials in road construction. The Guidelines were recently updated to include current information about the U.S. EPA's Resource Conservation Challenge priority materials, coal ash, foundry sands and construction and demolition materials, along with current information about environmental considerations in the use of byproduct materials.

The Industrial Resources Council (IRC)
The IRC's website provides comprehensive technical information on utilizing industrial materials in various road construction applications, including structural fill, embankments, road base, etc.

Recycled Materials Resource Center (RMRC)
The RMRC's mission includes systematically testing, evaluating, developing appropriate guidelines for and demonstrating environmentally acceptable increased use of recycled materials in transportation infrastructure construction and maintenance. The RMRC website provides information on recycling and reusing industrial materials in roadways.

FHWA Office of Pavement Technology: Recycling Homepage

EPA's Comprehensive Procurement Guidelines (CPG)
Contains information and links to construction and transportation products containing recycled content. Although the CPGs are primarily for federal procuring agencies, the information is useful to state and local governments and the private sector. You also can also view EPA's recommended recycled-content ranges and access a Supplier Database which includes manufacturers, vendors, and suppliers for each item.

Industry Partners Information: research reports, case studies, contact info:

American Coal Ash Association (ACAA) - Coal Combustion Products

Construction Materials Recycling Association (CMRA) - Construction and Demolition Materials

Foundry Industry Recycling Starts Today (AFS-FIRST) - Foundry Sands and Slags

National Council for Air and Stream Improvement (NCASI) - Pulp and Paper Industry Materials

National Slag Association (NSA) & Slag Cement Association - Iron and Steel Slags
www.nationalslag.org; www.slagcement.org

Rubber Manufacturers Association (RMA) - Scrap Tires


Coal Combustion Products Partnership's (C2P2) Highways Applications
Provides links to technical publications and fact sheets on the use of coal combustion products in highways, including:

  • Using Coal Ash in Highway Construction: A guide to Benefits and Impacts
  • Fly Ash Facts for Highway Engineers
  • Assessing Groundwater Impacts from Coal Combustion Products Used in Highways

Visit: http://www.epa.gov/epawaste/partnerships/c2p2/use/highway.htm

Federal Highway Administration Guidebook on Fly Ash

Foundry Sand Facts for Civil Engineers, FHWA-IF-04-004, May 2004
https://www.fhwa.dot.gov/pavement/pubs/013791.pdf (.pdf)

Report on Use of Recycled Foundry Sand in the Cleveland Area
FHWA report providing a review on the uses of foundry sand in roadway construction around the Cleveland, Ohio area.
www.fhwa.dot.gov/pavement/recycling/cleveland.cfm (.pdf, 0.4 mb)

Guidebook on Ground Granulated Blast Furnace Slag - FHWA

Guidebook on Silica Fume -FHWA

Recycled Concrete Aggregate: Transportation Applications

Recycled Materials in European Highway Environments: Uses, Technologies, and Polices
Federal Highway Administration sponsored document that reports on innovative policies, programs, and techniques that promote the use of recycled materials in the highway environment.
http://international.fhwa.dot.gov/pdfs/recycolor.pdf (.pdf)

FHWA Policy and Technical Advisories

Federal Highway Administration (FHWA) Recycled Materials Policy
FHWA's policy statement is designed to advance the use of recycled materials in highway applications. The policy outlines the importance of re-using materials previously used in constructing the Nation's highway system, and calls upon the FHWA and State transportation departments to explicitly consider recycling as early as possible in the development of every project.

Technical Advisory T 5080.9. Use of Coal Ash in Embankments and Bases.
U.S. Department of Transportation, Federal Highway Administration, May 1988

The purpose of this technical advisory is to set forth guidance and recommendations relating to the use of coal ash in bases and embankments. This Technical Advisory covers the history of coal ash use in these applications along with discussions on environmental, design, and construction considerations. https://www.fhwa.dot.gov/pavement/t508009.cfm

Technical Advisory: Use of Recycled Concrete Pavement as Aggregate in Hydraulic-Cement Concrete Pavement
This Technical Advisory issues information on state-of-the-practice and guidance for the use of recycled concrete pavement as aggregate in concrete used for pavements.


American Association of State Highway and Transportation Officials (AASHTO)
The AASHTO Subcommittee on Materials focuses on developing specifications for materials used in the construction and maintenance of all transportation facilities including highways, bridges and structures, and standard methods of sampling and testing these materials; and serves as a conduit to exchange information on the performance of special products evaluated by AASHTO Member Departments. The Subcommittee on Materials also maintains and updates the Standard Specifications for Transportation and Methods of Sampling and Testing, and Provisional Standards Materials reference which contains 418 materials specifications and test methods commonly used in the construction of highway facilities.

Recycled Materials Resource Center (RMRC) Project 13/14: The Development and Preparation of Specifications for Using Recycled Materials in Highway Applications
RMRC's project 13/14 focused on the development of specifications for recycled materials in highway construction. The RMRC is funded by the Federal Highway Administration and the U.S. Environmental Protection Agency.
http://www.recycledmaterials.org/Research/past/P13&14/p1314summary.pdf (.pdf)

National Standards/Specifications
The Recycled Materials Resource Center has consolidated a listing of standards and specifications for use of industrial materials in roadways. Visit http://www.recycledmaterials.org/tools/uguidelines/standards.asp for standards/specifications on:

  • Coal Fly Ash
  • Coal Bottom Ash/Boiler Slag
  • Foundry Sand
  • FGD Scrubber Material
  • Roofing Shingles
  • Reclaimed Asphalt
  • Reclaimed Concrete

FHWA National Highway Specifications Website
Developed and maintained by the FHWA, this website consists of a searchable library of highway specifications from across the nation.

State Specifications/Provisions on Recycling Technology

National Highway Specifications Website
This site serves as a clearinghouse and electronic library where users can search, review, cross-reference, and download the most current specifications, construction manuals, and drawings. Although this site is maintained by the Federal Highway Administration, the materials on this site have been submitted by State Departments of Transportation and other agencies.

State Transportation Websites
Links to state transportation websites from the Federal Highway Administration website

Engineering and Environmental Specifications of State Agencies for Utilization and Disposal of Coal Combustion Products: Volume 1 – DOT Specifications 2005–EERC–07–04 The Energy & Environmental Research Center at the University of North Dakota conducted a state by state comparison of U.S. Department of Transportation specifications for using coal combustion products.

University of Wisconsin's Beneficial Use Information Center (BUIC)
The BUIC is a virtual center created by the Geotechnical/Geoenvironmental Group at the Department of Civil and Environmental Engineering at the University of Wisconsin-Madison to provide a location where designers and users can access information, including specifications, relevant to the beneficial reuse of foundry byproducts.

  • Flowable Fill Specifications for Foundry Sand Use in Select States
  • Specification for Foundry Sand Used as Fill Material
  • Specifications for Foundry Sand Used in Portland Cement Concrete
  • Specifications for Foundry Sand Used in Asphalt Concrete
  • Specifications for Foundry Sand Used in Portland Cement Manufacturing
  • Specifications for Foundry Sand Used in Growing Mix
  • Specifications for Foundry Sand Used as Landfill Liners and Covers

Indiana Department of Transportation (InDOT) Standard Specifications
Pages 693-696 covers fly ash and ground granulated blast furnace slag used as a pozzolan; and pages 697-699 addresses silica fume used as a pozzolanic mineral admixture.

Illinois DOT Specifications – Materials

Caltrans Standard Specifications May 2006
Pages 229-236 address reclaimed base/subbase; pages 329-33 cover fly ash for grout; and pages 751-752 cover the recycled materials for Portland Cement concrete.

Texas Department of Transportation Specifications for Recycled Materials

Resources for Assessing Risk in Roadway Environments

Evaluation of Industrial Waste Evaluation Model (IWEM) For Non-Federal Users With Regard to Highway Applications
Funded by the U.S. EPA, the Recycled Materials Resource Center conducted work to evaluate whether IWEM can be used as a predictive tool to accurately determine whether leaching from materials will result in significant changes in groundwater concentrations when the materials are reused as a base or sub-base in a roadway. Click on the link and scroll down under “Key Resources.”
Visit: Evaluation of IWEM For Non-Federal Users With Regard to Highway Applications

Geo Engineering Report No. 05-22: Assessing Groundwater Impacts from Coal Combustion Products Used In Highways
The Department of Civil and Environmental Engineering at the University of Wisconsin-Madison evaluated a computer application, called WiscLeach, that was developed to assess impacts to groundwater caused by leaching of trace elements from coal combustion products used in highway construction. This study was funded by the Wisconsin Department of Natural Resources Waste Reduction and Recycling Demonstration grant Program and Alliant Energy.
Visit: Geo Engineering Report No. 05-22: Assessing Groundwater Impacts from Coal Combustion Products Used In Highways

Geo Engineering Report No. 05-21: Metals Leaching from Highway Test Sections Constructed with Industrial Byproducts
Describes the results of a study by the Department of Civil and Environmental Engineering at the University of Wisconsin-Madison to assess metals leaching from industrial byproducts (foundry sand and foundry slag from a gray-iron foundry; and bottom ash and fly ash from a coal-fired power plant) used in highway construction. This study was funded by the Recycled Materials Research Center through the Wisconsin Department of Transportation, the Wisconsin Department of Natural resources Waste reduction and recycling Demonstration Grant Program, and Alliant Energy.
Geo Engineering Report No. 05-21: Metals Leaching from Highway Test Sections Constructed with Industrial Byproducts

Case Studies

EPA's Coal Combustion Products Partnership Program Case Studies
Visit http://www.epa.gov/epawaste/partnerships/c2p2/cases/index.htm for a comprehensive listing of case studies exhibiting the use of coal combustion products. Featured roadway case studies include:

  • Fly Ash Sub-Grade Stabilization and PPC Optimization, Washburn Municipal Airport
  • Fly Ash Concrete Design for Chicago's 100-Year Road Structure
  • Fly Ash for Highway Construction and Site Development
  • Full Depth Reclamation - A Rehabilitation Option for Deteriorated Hot Mix Asphalt Pavements
  • Fly Ash in California's Olivenhain Dam

Coal Fly Ash Used on Ohio Full Depth Reclamation Projects

Indiana Department of Transportation (InDOT) Case Studies #1-6
These case studies can be found on the EPA's "Success Stories" website. Click here and scroll down to "Indiana DOT Case Studies."

  1. Use of Bottom Ash in an Embankment
  2. Use of a Mixture of Bottom Ash and Fly Ash in an Embankment
  3. Use of a Mixture of Fly Ash and Bottom Ash in an Embankment
  4. Use of Foundry Sand in an Embankment
  5. Use of Shredded Tires in an Embankment
  6. Use of Crushed Glass as Backfill
    • Use of Fly Ash in Embankments
    • InDOT BU Case Study Documentation

Wisconsin DOT Case Studies #1-2
These case studies can be found on the EPA's "Success Stories" website. Click here and scroll down to "Wisconsin DOT Case Studies."

  1. Use of Fly Ash in an Embankment
  2. Use of Fly Ash to Stabilize Soils
  • Presentation on WisDOT Fly Ash Stabilization Experiences

Foundry Industry Starts Recycling Today (AFS-FIRST) Roadway Case Studies
The AFS-FIRST website provides several case studies on the beneficial use applications for spent foundry sand under the "Technical Applications" tab. The initial case studies were developed for AFS-FIRST under a grant from U.S. EPA Region 5. Registered users of the foundryrecycling.org Web site can download these case studies. Registration is free.

  • Foundry Sand as an Asphalt Pavement Ingredient
  • Foundry Sand as Structural Fill and Road Base
  • Foundry Sand as Sub Base for an Airport Runway
  • Foundry Sand for Roadbase and Manufactured Soil
  • A Resource Recovery Cooperative

National Slag Association (NSA) Roadway Case Studies
The NSA website provides several cases studies on the beneficial use applications for slag under the "Research/Library" tab.

  • Sudden Stops and Starts Don't Bother the Illinois Tollway Plazas Anymore

  • Largest Stone Matrix Asphalt Project in USA Spans 6 lanes for 8 Miles

  • NASCAR Drivers Know a Smooth Surface Starts with a Strong Foundation

  • Slag Fills Six Miles of Two New Concrete Lanes on Busy I-65 in Hobart, Indiana

  • Once Again Slag Proves "Less is More" on Michigan's M-63 in Benton Harbor

  • I-70 through Colorado's Glenwood Canyon

  • Lightweight Slag – the Product of Choice for Highway 17 in Renfrew, Ontario

  • Air Cooled Blast Furnace Slag is Major Component of NCAT Test Track Research

  • "Whitetopping" Thin Concrete Overlays Use Blast Furnace Slag in Wayne County, Michigan

  • Department of Defense Paving Materials Highlight Environmental Attributes
    An Environmentally Preferable Purchasing Case Study successfully used recycled content products, such as asphalt and concrete.

  • Kukkia Circlet Environmentally Friendly System to Renovate Secondary Roads
    A research and demonstration project in Finland on the use of boiler ash and wastewater residual solids from pulp and paper mills in improving unpaved roads.

Benefits of Using Industrial Materials

EPA's C2P2 Website: Benefits of using CCPs
Using CCPs in an environmentally safe manner saves virgin resources, and reduces energy consumption and greenhouse gas emissions (GHG). In addition, it helps reduce the need for landfill space and new landfills. CCPs also makes good economic sense, they are often less costly than the materials they replace. This site gives an overview of these beenfits.

Beneficial Reuse Model (BenReMod)
BenReMod is a model that allows state and local regulators, end users, and the public to evaluate the benefits and disadvantages of using recycled materials in road construction. It is currently being developed by the University of Toledo in partnership with the American Coal Ash Association, Great Lakes Byproducts Management Association, and the Ohio Environmental Protection Agency.

Mid-Atlantic Green Highway Partnership

Green Highways Partnership- Recycling and Reuse of Industrial Materials Team
Information on recycling and reusing industrial materials in roadways, which is a component of the Mid-Atlantic Green Highways Partnership.

Finding Suppliers of Industrial Materials

This EPA website offers links to industrial materials suppliersand C&D materials recyclers.

Updated: 08/22/2018
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