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

II. Opening Session

The workshop opened with an introduction by Ms. Katherine Holtz of the Texas DOT. She was followed by Mr. Vince Schimmoller of the FHWA, Ms. Jean Schwab of the U.S. EPA, and Mr. E. Dean Carlson of AASHTO. All officials support the need for better cooperation and that recycling needs an integrated approach. Mr. Schimmoller believes that an integrated program could be prepared in advance for the next highway reauthorization. It should address and support a cooperative, rather than a regulatory approach to recycling issues. Mr. Carlson noted that more should be done in the recycling area but that there has been some backlash from the ISTEA-forced use of crumb rubber. The resources to change the requirement were extremely high. The legislation may even have been counterproductive in promoting the use of crumb rubber. Ms. Schwab believes that EPA would be very open to working with all concerned parties in a cooperative spirit, especially in the area of the comprehensive procurement guidelines[2]. The EPA, however, is severally restricted with few, if any, discretionary funds for them to conduct outreach programs.

The opening remarks were followed by presentations aimed at stimulating discussion, especially during the brainstorming segment of the workshop.[3] The keynote presentation was entitled, "Life Cycle Assessment of Civil Infrastructure Systems," and presented by Dr. Arpad Horvath of the University of California at Berkeley. Dr. Horvath's presentation addressed several of the many technical, economic, and environmental factors in sustainable development, which require interdisciplinary approaches, and private and public partnerships. While sustainable development and better environmental quality are becoming important social goals, their analysis and implementation are complicated by the existence of so many interdisciplinary factors. Dr. Horvath explained how life-cycle assessment (LCA) is emerging as the most promising approach to such an analysis. Dr. Horvath also presented what is considered to be the state-of-the-art model in LCA and he provided some real life examples, comparing asphalt with concrete pavements.

Dr. Taylor Eighmy of the Recycled Materials Resource Center (RMRC) presented a national look at the recycling efforts in the U.S., a review of EPA and Environmental Council of States activities, the ASTSWMO beneficial use survey, and the activities underway at the Center. The Center is supported by a cooperative agreement with the FHWA.

Several European representatives were invited to the U.S. to present their programs and share their experiences. Dr. Jan van der Zwan, Ministry of Transport, Public Works, and Water Management in the Netherlands, discussed the Netherlands approach to recycling. The Netherlands has formal legislation encouraging recycling in the highway environment as part of their broad sustainability policies. The Netherlands is extremely successful in recycling the highway environment. He reiterated that each country has its own culture and must integrate recycling into that culture. Government must set the preconditions (policies) for improving the recycling atmosphere. Industry must develop its own sales efforts, invest in recycling, organize themselves, understand the social problems, and work to locate markets for their products. Both must work together to set research agendas and technical standards.

Mr. Karsten Ludvigsen, RGS 90, Denmark, presented his company's total concept for recycling and selling recycled materials for the construction industry. The RGS 90 is a unique company with significant ownership by the public sector. RGS 90 was formed as a result of Denmark's unique lack of natural resources and its assertive governmental taxation policy. He presented the Copenhagen example of full recycling where literally all materials in a building or roadway will be sorted for reuse in highway construction. He reiterated that it is market economics that fundamentally drive such a policy.

Dr. Hans van der Sloot of Netherlands Energy Research Foundation (ECN) talked about the European leaching protocols. The talk centered around the ECN 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[4]. That Committee is developing standardized protocols for scenario-specific evaluation of recycled materials uses.[5]

Dr. Heinrich Werner of the German Federal Highway Research Institute (BAST) provided a presentation on accelerated testing of recycled materials. Germany has the need for large quantities of materials for the increased construction underway in the former East Germany. This increased construction activity is also generating a significant amount of recycled materials. Dr. Werner discussed accelerated testing of pavements made with recycled materials. The work he presented was completed at the BAST accelerated testing facility using an impact loader to simulate truck traffic while road sections were subjected to various freeze/thaw cycles. The results were very performance-related and allowed them to make value judgments based on degradation, permeability, and rutting potential of the various materials. Most of the recycled materials (recycled asphalt pavement, construction and demolition aggregates) performed as well as natural aggregates. Conventional testing (triaxial compression) did not correctly predict performance.

Dr. Hans G. Johansson of the Swedish National Road and Transport Research Institute (VTI) presented a paper on the ALT-MAT Project (ALTernative MATerials in Road Construction). The project was funded by the European Commission[6] and was carried out by a consortium of nine organizations in seven countries. The objective was to develop test methods and evaluate field performance to assess the suitability of alternative materials in road construction, concentrating on unbound granular applications. The project activities were described and a tool kit of test methods for mechanical, leaching and hydrodynamic properties were presented. Case studies of the performance of alternative materials in roads showed that they give as good performance as natural reference materials and have not caused pollution of groundwater.

Other U.S. speakers included Dr. John Stutz and Ms. Rebecca Davio, TX DOT. Dr. Stutz of the Tellus Institute delivered a presentation entitled, "Applying Life-Cycle Thinking to Highway Materials." Dr. Stutz described the life-cycle approach and how it applies to highway materials. Life-cycle Thinking is more qualitative and considered less exhaustive than Life-cycle Analysis. Dr. Stutz supported the integration of recycling into the early project and product decision-making; considering alternative uses early can help generate lower overall costs.

Ms. Rebecca Davio discussed the 7-step program for establishing successful DOT recycling programs. It includes (1) the need to think of recycled materials as a valuable resource, not as wastes; (2) ensure engineering and environmental quality in recycled materials; (3) use incentives rather than mandates to encourage recycled material use; (4) develop specifications that allow for recycled materials; (5) make as few procedural changes as possible to accommodate recycled materials; (6) publicize the program broadly; and (7) get started and make a difference.

The session closed with a panel discussion. The panel members were asked to comment on the adoption of closed material cycles[7], 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. Members of the panel included:

  • Doug Pitcock, Williams Bros., Associated General Contractors and the Association of Road and Transportation Builders of America
  • Paul Wells, Chief Engineer, NY DOT
  • Dale Thompson, MN Pollution Control Agency and Chair of the ASTSWMO Beneficial Use Task Force
  • Jean Schwab, U.S. EPA
  • Vince Schimmoller, FHWA
  • Dave Newcomb, Vice President, Engineering, National Asphalt Pavement Association (NAPA)

Mr. Pitcock is the owner of one of the largest construction companies in the U.S. and has a strong background in recycling materials. He considers recycling of asphalt and concrete aggregate standard practice that supports his competitiveness, not simply profit.

Mr. Wells believes that the DOTs can act as change agents - being a catalyst for better use of recycled materials. While there is always pressure to use higher quality materials, performance-related specifications can really help the DOTs avoid direct material (method) specifications. He supported all types of partnerships to get this accomplished.

Mr. Thompson explained the ASTSWMO's Beneficial Use Report. A material is considered an industrial byproduct and not an industrial solid waste when it is shown that the material is being used or reused as an ingredient in an industrial process to make a product. He revisited earlier remarks about how difficult it is to make decisions across state lines and within each jurisdiction.

Ms. Schwab discussed EPA and its very limited role it has in this area. If it is designated as non-hazardous, the states and the local communities generally will be held responsible for disposal and use of the material. She believes that there is some possibility of incentive-based legislation. So far as incentive-based taxing, the EU countries generally own the landfills and are able to set social policy. In the U.S., most landfills are owned by the private sector. If a higher value is place on the material before it goes to the landfill, then it may go elsewhere.

All supported the general themes from the previous speakers. They all reemphasized that economics are extremely critical, as are incentive programs. Improving working relationships among the various disciplines will do much to improve the process.

This concluded the open sessions. The remaining workshop time was allocated to public sector officials.

[2] The Comprehensive Procurement Guideline (CPG) program is part of EPA's effort to promote the use of materials recovered from solid waste. The CPG program is authorized by Congress under Section 6002 of the Resource Conservation and Recovery Act (RCRA) and Executive Order 13101. EPA is required to designate products that are or can be made with recovered materials, and to recommend practices for buying these products. Once a product is designated, procuring agencies are required to purchase it with the highest recovered material content level practicable.

[3] The PowerPoint presentations can be found at

[4] CEN/TC 292 is the Committee European de Normalization that consists of seven working and three ad hoc groups harmonizing leaching and extraction tests.

[5] This work is particularly important, as work done under NCHRP 25-09, "Environmental Impact of Construction and Repair Materials on Surface and Ground Waters," is of a similar nature. The NCHRP 25-09 work is about to be released.

[6] The European Union--previously known as the European Community--is an institutional framework for the construction of a united Europe. It was created after World War II to unite the nations of Europe economically. Fifteen countries are members of the European Union, and some 370 million people share the common institutions and policies.

[7] A closed material cycle suggests that all material introduced into a highway construction project may be beneficially reused at some later date.

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John Bukowski
Office of Asset Management, Pavements, and Construction
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Updated: 04/30/2015

United States Department of Transportation - Federal Highway Administration