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Partnerships for Sustainability A New Approach to Highway Material
A Report on the Houston Workshop


Note: Appendices 1and 2 are attached. The rest are posted on the web - under Sustainability.

  1. Agenda
  2. Summary of Scan Trip
  3. "Life Cycle Assessment of Civil Infrastructure Systems" by Dr. Arpad Horvath, University of California at Berkeley
  4. "National View" by Dr. Taylor Eighmy, Recycled Materials Resource Center
  5. "Dutch Sustainability Initiative" by Dr. Jan van der Zwan, Ministry of Transport, Public Works, and Water Management in the Netherlands
  6. "DOT Recycling: Seven Steps" by Ms. Rebecca Davio, TX DOT
  7. "European C&D Recycling" Mr. Kartsen Ludvigens, RGS 90, Denmark
  8. "Applying Life-Cycle Thinking to Highway Materials" Dr. John Stutz, Tellus Institute
  9. "European Leaching Protocols" by Dr. Hans van der Sloot, Netherlands Energy Research Foundation (ECN)
  10. "Accelerated Testing in Germany" Dr. Heinrich Werner, German Federal highway research Institute
  11. "Alt Mat Research" by Dr. Hans G. Johansson, Swedish National Road and Transport Research Institutes

Appendix 1.

Partnerships for Sustainability
"A New Approach to Highway Materials"
General Session

Houston, Texas
October 9-11, 2000


This workshop follows upon a successful Federal Highway Administration Technology Scanning Tour of Europe in September 1999. The purpose of the Scan was to explore European advances in recycling in the highway environment. The Scan Team was so impressed with what they saw and heard on the tour that they helped organize this workshop so that more people in the US could benefit from this information.

The first day of the workshop is tailored to knowledge sharing. The second and third days are specifically directed to Federal and State DOT and EPA materials engineers and environmental staffs to 1) find common ground and 2) to encourage working together on all aspects of recycled materials use within the highway environment.

Monday, October 9

8:00 AM Welcome, Hosted by Texas Department of Transportation Ms. Katherine Holtz, Director, Materials Section

  • Mr. Vince Schimmoller, Program Manager, Department of Transportation, Federal Highway Administration, Infrastructure Core Business Unit
  • Ms. Jean Schwab, Environmental Protection Agency, Solid Waste Division -, Municipal Information and Analysis Branch, Solid; Municipal and Industrial Solid Waste Division
  • E. Dean Carlson, American Association of State Highway and Transportation Officials, Secretary of Transportation, Kansas DOT

8:30 AM Keynote Presentation - "Life Cycle Assessment of Civil Infrastructure Systems" by Doctor Arpad Horvath, Assistant Professor, Department of Civil and Environmental Engineering, University of California at Berkeley

While sustainable development and better environmental quality are becoming important social goals, their analysis and implementation are complicate by a myriad of technical, economic, environmental and organizational factors that require interdisciplinary approaches and private and public partnerships. Life-cycle assessment is emerging as the most promising approach to such an analysis, from the material extraction phase through the end-of-life phase. As the economic and environmental implications of construction, operating, and decommissioning of civil infrastructure systems are significant, environmental issues must be seriously considered. Dr. Horvath will present the state-of-the-art in life-cycle analysis and provide real life examples.

Overview Theme

9:00 AM "National View" by Taylor Eighmy Recycle Materials Resource Center

Dr. Eighmy will speak about (i) trends in recycling in the U.S. highway environment, (ii) recent FHWA and NCHRP research projects related to recycling, (iii) recent U.S. EPA and Environmental Council of States activities, (iv) the recently completed Association of State and Territorial Solid Waste Management Officials beneficial use survey, and (v) the Recycled Materials Resource Center outreach and research activities.

9:40 AM "Dutch Sustainability Initiative" by Dr. Jan van der Zwan The Netherlands Public Works Agency

Dr. van der Zwan will talk about the Dutch Sustainability initiative, the role of CROW in setting standards, and general Dutch successes in recycling in the highway environment.

10:30 AM Break

10:45 AM "DOT Recycling: 7 Steps" by Rebecca Davio TX DOT

Ms. Davio will provide tips on how to start a DOT recycling program encouraging the use of recycled materials in road construction and maintenance projects. Her presentation will draw on 5 years experience by the Texas Department of Transportation.

Economic Theme

11:15 AM "European C&D Recycling" by Mr. Karsten Ludvigsen RGS 90, Denmark

Mr. Ludvigsen will talk about the role of legislation in promoting recycled materials uses and the successes of the RGS 90 company in acting as a collector, processor, and distributor of recycled materials used in Danish highway construction; particularly about the use of high quality C&D aggregates.

11:55 AM "Applying Life-Cycle Thinking To Highway Materials" by Dr.John Stutz, Tellus Institute

Dr. Stutz will begin by describing the life-cycle approach and how it applies to highway materials. He will discuss the logistics and economics of recycling highway materials, from the waste generators' and recyclers' perspective. He will also discuss opportunities for the use of other recovered materials, such as compost. Policies that would harmonize construction practice with the solid waste management hierarchy will receive particular attention.

12:30 PM Lunch

Environmental Theme

1:30 PM "European Leaching Protocols" by Dr. Hans van der Sloot Netherlands Energy Research Foundation

Dr. van der Sloot will talk about the ECN (Dutch) leaching database (on 25 recycled materials), the Dutch leaching methods and evaluation protocol related to the Dutch Building Materials Decree, and the activities of the European Union's CEN TC 292 Committee that is developing protocols for scenario-specific evaluation of recycled materials uses.

2:30 PM Break

Engineering Theme

3:00 pm "Accelerated Testing in Germany" by Dr. Heinrich Werner, Dipl. Ing. German Federal Highway Research Institute

Dr. Werner will talk about accelerated testing of pavements made with recycled materials. The work was done at BASt in their accelerated testing facility using an impact loader to emulate truck traffic while road sections were subjected to various freeze/thaw cycles.

3:40 PM "Alt Mat Research" by Dr. Hans G. Johansson, Swedish National Road and Transport Research Institute

"Dr. Johansson will present the findings of a European Commission Fourth Framework collaborative research project on alternative materials in the highway environment. Research from six countries on seven different types of recycled materials will be highlighted.

4:15 PM Break

4:30 PM Policy Panel "New Approaches to Recycling Materials" Moderator, Shari Shaftlein, Washington DOT

ARTBA/AGC Doug Pitcock, Williams Bros., AGC/ARTBA
AASHTO Paul Wells, Chief Engineer, NY DOT
ASTSWMO Dale Thompson, MN Pollution Control Agency and Chair of ASTSWMO Beneficial Use Task Force
EPA Jean Schwab, EPA
FHWA Vince Schimmoller, FHWA
NAPA Dave Newcomb, Vice President, Engineering, National Asphalt Pavement Association

The panel will be asked to comment on thee adoption of closed material cycles, on maximizing recycling by balancing economics, environment, and engineering, the role of public and private alliances to promote sustainability concepts and the possibility of any legislative initiatives to promote the cause.

5:15 PM Workshop Instructions

5:30 PM Reception

Partnerships for Sustainability
A New Approach to Highway Materials
Workshop Sessions


The highway materials and solid waste communities are working together on a common agenda to satisfy the sustainable needs of future generations.

Specific Goals of the Workshop Portion
  • Better understand of each other's organizational roles and responsibilities in the environmental arena.
  • Establish the beginnings of a working arrangement for the future.
  • Understand each segment of the Highway Materials - Environmental relationship
  • Understand terms such as "highway materials, beneficial use, and sustainability" as they relate to each other's current work effort.
  • Define "partnerships" that would help fulfill our vision
    • Three levels - national, state, association
Tuesday October 10 AM Session

8:00 am "What do you do for a living?" Ferragut, Moderator

During this session, selected attendees will discuss what they do for a living. What kind of everyday issues they face, what limitations they have, what technology gaps they face of key issues, and what political/social pressures dictate the pace of environmental life in their organization. We will also share different unique partnerships that have been established

We will start with VERY BRIEF Presentations by DOT Materials Engineers, State DOT Environmental Engineers, State Environmental Engineers, Association Managers, FHWA, and EPA, followed by an open discussion

10:00 am Breakout Sessions

We will break into smaller groups. One group will consist of national representatives from EPA, FHWA, and the Associations with a few state representatives. The other group will consist of state representatives will address issues pertaining to HIGHWAY MATERIALS and INDUSTRY BY-PRODUCTS, PARTNERSHIPS, and SUSTAINABILITY. Each group will have a list of feeder questions.

12:00 noon Box Lunch and Field Trip - Sponsored by the AGC of Texas

6:30 PM Dinner Sponsored by Rubber Pavements Association

Wednesday October 11 AM Session

07:30 am Breakout Sessions (continued)

We should finish what we started yesterday morning. Look for some adjustments to this schedule based on the progress we showed the previous day.

09:00 am Summary Team Formation

Two representatives from each group will meet to organize a presentation to the general session. The others? We will be asking the individual state teams to meet and to pull together summary thoughts on the past two days and present different items on how they may work together better to promote environmental issues within the state borders.

10:30 am Presentation and Round Table Discussion

Leaders will make the formal presentation and then have an open session for discussion. We will then hear from the different state delegations.

11:30 am Closing

We will discuss the final report, when it should be ready for review and comment, and how we should distribute it. Then expect a little motivation, pep talk.

12:00 noon Adjourn

Appendix 2.

Summary of FHWA International Technology Scanning Program For
Recycled Materials Use in Highway Environments: Uses, Technologies and Policies


The use of recycled materials in the highway environment has been occurring with varying degrees of success in the United States for the last 20 years; notably with recycled asphalt pavement (RAP), reclaimed concrete pavement, coal fly ash and blast furnace slag. The U.S. Congress, in the 1998 Transportation Equity Act for the 21st Century (TEA-21), established the Recycled Materials Resource Center (RMRC) at the University of New Hampshire (UNH) to use research and outreach to reduce barriers to recycling in the highway environment. Congress also stipulated that recycled materials be researched to improve the durability of the surface transportation infrastructure. A number of states (e.g., Pennsylvania) and local governments have passed legislation to promote recycling in road construction. The private sector is developing innovations in processing and applications. Some states have beneficial use determination processes (BUDs) to evaluate uses; however, there is not uniformity among states. State Departments of Transportation (DOTs) and state environmental protection agencies (state EPAs) are trying to balance the desire for increased use of recycled materials with concerns about potential environmental impacts. There is an increasing interest within the highway community at all levels to learn more about advances in the use of recycled materials in the highway environment and how it relates to sustainability initiatives within the transportation sector.


The objective of this scanning tour was to review and document innovative policies, programs and techniques in Europe. Recommendations would be made that would lead to the reduction of barriers to recycled material use. Sweden, Denmark, Germany, the Netherlands and France were identified as nations that have active research, policies and programs promoting the reuse of recycled materials in the highway environment. The U.S. delegation met with over 100 representatives from transportation and environmental ministries, research organizations, contractors, and producers involved with recycled materials in the five countries.

The U.S. delegation was assembled under the Federal Highway Administration's (FHWA) International Technology Scanning Program. The panel was sponsored by FHWA, the American Association of State Highway and Transportation Officials (AASHTO) through the National Cooperative Highway Research Program (NCHRP), and the RMRC at UNH. The panel included members with expertise in materials, pavement engineering, pavement construction and recycling, beneficial use determinations, and environmental evaluation. They represented FHWA, U.S. EPA, state DOTs, the American Public Works Association (APWA), the National Asphalt Pavement Association (NAPA), and academia.


Recycling for Sustainable Road Construction: All the countries that were visited had recycling policies specifically or generally promoting sustainability. There is also a pervasive public culture about recycling and social democracy that promotes national behavior change. In many of the countries, there is an effective stakeholder consensus process that is used for developing engineering and environmental specifications. There are a wide variety of drivers that influence recycling success from national values to practical considerations at the regional level. Some of these drivers are: a lack of virgin material, public opposition to aggregate mining, high transportation costs, opposition to landfilling, and high population densities. In areas of the U.S. where similar drivers are present, European experiences may be transferred. In the Netherlands, the Dutch have a formal policy for sustainable development in highway construction that embraces the use of recycled materials. There is public opposition to landfills and excavation of natural materials. The government has a policy that minimizes the use of natural materials and promotes the use of recycled materials within a market system. The government cooperates with industry by sharing risk and profit and providing unambiguous technical and environmental standards. High degrees of recycling are seen, especially for construction & demolition (C&D) aggregates, blast furnace slags, recycled asphalt pavements (RAP), coal fly ashes, steel slags, and municipal solid waste incineration bottom ash. The government has helped to start companies specialized in the marketing of lightly contaminated soils for use in sound barriers adjacent to highways, fills and embankments. The success seen in the Netherlands is related to advances in all aspects of the sustainability model: a robust market, clear policy, economy, appropriate technical and environmental standards, and innovative technical processes that involve the private sector. The Dutch sustainability model has elements that should be considered in the U.S. transportation community's overall goals for transportation sustainability.

Economics: Engineering and environmental life cycle costs and benefits are the basis for many of the recycling initiatives in Europe. The free market generally plays a central role in all aspects of the highway recycling industry. Where this is not the case, government acts as a catalyst to establish a market. Tax structures (both incentives and disincentives) have played a large role in promoting recycling in the highway environment in Denmark, the Netherlands, and Sweden. There are taxes on the use of natural materials in Denmark and in the Netherlands. Restrictive landfill taxes and policies in the Netherlands, Denmark and France are also promoting recycling; in these countries, the landfills are frequently government owned. A pending European Union (EU) landfill directive for 2002 designed to limit the landfilling of inert materials also is influencing recycled material flow; many contractors in the five countries are positioning themselves to use more recycled materials. A number of materials like RAP, blast furnace slag, crushed concrete, and high quality C&D aggregates are of high engineering and environmental quality and compete favorably with natural materials. Demand for some of these materials in the Netherlands is so high that there are anticipated shortages. Engineering and, in some cases, environmental warranties reduce government or owner liability and are widely used and provide flexibility for the greater use of recycled materials. These warranties also drive innovative public sector research. There were widespread sentiments expressed in many of the countries that recycled materials should be evaluated on their technical merits for their highest possible use and not because of direct governmental mandates.

Engineering: Recycling is generally encouraged at the national level by transportation ministries who provide standardization, specialized testing, and performance evaluation. A number of countries require that recycled materials meet the same specifications as natural materials and provide equal performance. An approved product list is generally not used in the host countries, but rather ultimate performance is more a driver to promote recycled materials use. There is a general sense that recycled materials should be used in an application to return the highest possible value. As in the U.S., there is still concern that many engineering test methods do not predict true field performance, though ongoing research in Germany and Sweden with load simulators is addressing this. In the Netherlands, an innovative, Swiss-designed double drum hot-mix plant capable of recycling up to 70% RAP was observed. Companies that supply natural materials also supply recycled materials. Many countries utilize technical and environmental quality assurance/quality control (QA/QC) programs so the recycled materials have the same level of quality as natural materials. Frequently, the material processor or supplier is the certifying organization.

Environment: Recycling at the national level is accomplished by environmental ministries who develop laws and compliance structure. National environmental research laboratories are providing test methods and approaches to evaluate environmental performance and assist in setting standards. Implementation and regulation are occurring at the regional and local level. There is consistent agreement to move from laboratory work to performance modeling based on field validation. An EU 4th Framework Program project called Alternative Materials (ALT MAT) illustrates this approach and is a model for U.S. consideration. In the Netherlands, an environmental approval process is used that involves mechanistic leaching tests and application-specific evaluation of incremental impacts to background soils and groundwater. A large leaching database is also maintained at the Netherlands Energy Research Foundation. Within the EU, there are efforts toward standardizing an approach to evaluate the environmental performance of products, including highway materials. Lessons have also been learned from isolated examples of environmental problems created from storage, processing, transport or use of some materials. In some cases, public awareness and education efforts have been needed to overcome perceived environmental risks.


In the European countries that were visited, recycling occurs when it is economic to do so. Factors in the market place dominate, but are generally supported by government policies and regulations such as bans on landfilling, landfill taxes, and natural aggregate taxes. Generally, clear and unambiguous engineering and environmental test methods and performance standards help to reduce uncertainty and allow recycled materials to compete with natural materials. Where tests and standards do not exist, governments often support recycling by sharing risk.

This is somewhat contrasted with the U.S. situation. Some recycled materials like RAP, coal fly ash and blast furnace slag are widely used in a true free market situation because of their excellent performance and competitive costs. Other materials (e.g. foundry sands, steel slags) are used more locally in response to more specific local market forces. There is little federal government involvement, except for construction procurement guidelines for materials like coal fly ash. Rather, the situation is driven at the state level. For example, the State of Pennsylvania has adopted legislation to promote recycling in the highway environment. However, there is a wide range of engineering and environmental approaches to BUDs by the states. California, Illinois, Massachusetts, New Jersey and Pennsylvania are working to standardize the BUD process and create reciprocity. There are wide spread needs for clear engineering and environmental test methods and performance standards. The owner or contractor generally assumes risk. The states, academia and the private sector are conducting significant research.

Table 1 provides a summary of specific findings and corresponding recommendations for the U.S. situation. The final report will contain a more complete discussion and additional recommendations. The U.S. delegation will provide leadership in sharing these recommendations at a national level with their various constituencies. Tentative assignments to act on recommendations have been made in the table. The delegation believes it is particularly important to adopt aspects of the Dutch sustainability model as a means to promote recycling in the highway environment; this will be detailed further in the final report. Further implementation strategies for the U.S. delegation will include electronic and written distribution of the final report, presentations, published articles, and development of a web site.

Table 1: Summary of Findings and Recommendations
Subject Findings Recommendations [Lead Organization From Scanning Team to Act on Recommendation]
Recycling for Sustainable Road Construction The Dutch sustainability policy is centered on a market system where both policy and economy influence the market. There are clear and unambiguous technical and environmental standards. The government promotes recycling by using taxes as incentives or disincentives and by assisting start up companies. Technical processes are developed to assist in providing quality material.

A high degree of information and technology transfer was seen within various ministries and agencies within each country as well as between countries. The EU 4th Framework Program project "Alternative Materials" (ALT MAT) Project is one such example of cooperation and technology transfer.

There is a high degree of public awareness in Europe about recycling. Federal and local governments have excellent informational campaigns. There can still be concern at the public level. Non-governmental organizations (NGOs) are involved in policy development in the Netherlands.

  • Include a recycling strategy in the sustainability aspect of FHWA's and AASHTO's strategic plans and long-range research priorities [FHWA, AASHTO SCOE].
  • Create a framework for state DOTs to consider the use of recycled materials in project planning, alternatives analysis, and mitigation analysis [AASHTO SCOE, SOM].
  • Encourage state DOTs to conduct long-term materials supply plans and recycled materials availability plans [AASHTO SOM].
  • Develop clear engineering and environmental guidelines at the state and Federal level that are available for suppliers and decision-makers [RMRC].
  • Prepare a briefing document for the U.S. Congress and state legislatures [FHWA, RMRC].
  • Prepare a briefing document for environmental foundations [RMRC].
  • With the new FHWA-EU partnership negotiated under the EU 5th Framework Program, explore research coordination, technology transfer, and exchange of experts [FHWA, AASHTO, ASTSWMO, RMRC].
  • Hold a special TRB session on recycling in the highway environment [RMRC, FHWA, AASHTO, NAPA].
  • Develop a National Highway Institute course on recycling [RMRC].
  • Conduct a public awareness program [AASHTO, FHWA].
Economics Recycling successes in the Netherlands, Denmark and France are based in part on market opportunities for materials suppliers and contractors. Life cycle costs analyses (LCA), some using environmental costs, are used.
  • Encourage contractors to use their private markets as a place to innovate and develop technologies [NAPA].
  • Adapt current FHWA LCA procedures to include recycled materials; it should address environmental costs [FHWA, RMRC].
Engineering A number of countries are moving towards performance based design procedures and to accelerated testing to predict material performance. However, there is still concern that test methods do not predict true field performance.

A number of advances were observed in the (i) use of foam bitumen as a stabilizing agent for recycled materials used in sub-base and base course, (ii) hot recycling of RAP in a double drum system, and (iii) the use of C&D aggregates.

  • Conduct recycling demonstration projects about foam bitumen, hot recycling, C&D aggregate use [FHWA, AASHTO, NAPA, RMRC].
  • Encourage AASHTO and state DOTs to involve contractors more in committees establishing specifications [AASHTO].
  • Evaluate contractors with respect to use of recycled materials or environmental protection during contract performance reviews [AASHTO].
  • Develop and implement the use of warranty and performance based specifications.
Environment The Netherlands uses a hierarchy of mechanistic leaching tests of both recycled materials and their highway products to look at cumulative release of constituents and their marginal impacts to soils and ground water. This is also generally the basis for an EU normalization activity to adopt this approach.

Efforts are underway to create a European database on product leaching.

Innovations are occurring in France on the use of tires and plastics in appurtenances.

There is coordination between transportation and environment ministries.

Many countries expressed a need to develop an approach to evaluate the environmental behavior of recycled materials and natural materials by looking at source terms, the fate and transport of their constituents, and their relation to human health and ecological risk.

  • Make connections to the European efforts to establish a leaching database [RMRC].
  • Hold an AASHTO and state EPA workshop on the Dutch and European Union approach to evaluating product-leaching behavior [RMRC].
  • Include state DOT Environmental Staff and state EPA staff on Innovations and New Product Reviews [AASHTO].
  • Develop a model GIS layer to track recycled material use and aid future maintenance and management decisions.
  • Add an "Excellence in Recycled Materials Innovation" category in the annual FHWA Environmental Excellence Awards and the AASHTO Environmental Best Practices Award [FHWA, AASHTO].
  • Encourage the U.S. EPA to work more with the state BUD programs to expand reciprocity [U.S. EPA].
  • Encourage the U.S. EPA to continue to develop the federal procurement guidelines for recycled materials use in the highway environment [U.S. EPA].
  • Perform long term monitoring [AASHTO, state EPAs].
  • Hold a workshop on issues related to source term description, fate and transport, and risk [RMRC].

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John Bukowski
Office of Asset Management, Pavements, and Construction
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Updated: 02/20/2015

United States Department of Transportation - Federal Highway Administration