Environmental issues are changing research, design, composition and placement of asphalt pavements around the world. And rightly or wrongly, fears of global climate change may forever change how asphalt is refined and placed and how -- or whether -- roads will be built. 

The delegates heard these messages -- in addition to a cornucopia of technical presentations on every aspect of asphalt production and paving -- at the Eighth International Conference on Asphalt Pavements, held Aug. 10-14, 1997 at the University of Washington-Seattle. 

This most recent incarnation of the original "Ann Arbor" conference, held every five years, included 104 technical papers contributed by authors from 20 countries on five continents. 
 

Environment No. 1 issue 

The No. 1 issue is the environment, said Mike Acott, president of the National Asphalt Pavement Association, during the opening session Monday, Aug. 11. "If you look back 10 years [one can see] the incredible impact the environment has had on all of us." 

• These environmental issues include, he said:
• Social, safety, and health issues related to climate change
• Clean air issues and regulations
• Occupational safety and health issues
• Disposal of wastes and solvents
• Recycling of pavements and waste materials in pavements
• Traffic demand management (congestion mitigation) vs. road building
• Mass transit funding vs. road funding, and
• Wetlands protection.

Changes in how freight is moved is impacting asphalt pavements, he said. Higher truck tire pressures, and the rapid evolution of "just-in-time" freight delivery -- in which parts are "warehoused" in trucks on roadways prior to delivery at a plant, enabling a manufacturer to reduce inventories -- is putting increased wear on roads. 
 

Consolidation driving change 

Acquisitions and mergers in the construction materials industry -- including hot mix asphalt and aggregate sector -- and the downsizing of marketing operations in the oil industry are driving change in the asphalt community, Acott said. 

In the public sector, government agency reorganization and "reinventing" is leading to major downsizing, he said. "It's leading to major skill losses and changes in way the public does business, placing much greater responsibility on contractors." 

In many countries, funding shortfalls are crippling the ability of their road infrastructure to handle phenomenal increases in loading. "Government domestic spending restrictions are lessening funds for highways," Acott told the opening session. 

"This is compounded by the diversion of highway funds from highway purposes," he said. "This disinvestment in roads has resulted in deterioration in the condition of highway pavements, increased traffic congestion and increased safety concerns." 

In the face of this, private sector funding is being used increasingly to fund major road construction projects, despite some reluctance on the part of communities to accept toll roads, he said. 
 

Areas of change 

Acott identified areas of change in the asphalt industry in worldwide. 

Partnerships are among them. The United States lags other countries -- like Japan, Australia, South Africa, and those in Europe -- in exploring "partnerships" in research and road construction between public and private sector entities, but that's changing, Acott said. 

"This is one area that will see significant growth," he said. "It's reflected in joint research, improved communication, joint training programs, study tours and technical working groups." 

Another is environmental safety and health. "For us this is the major issue," Acott said. In the United States, NAPA has focused on clean air act requirements, recycling of waste products, and asphalt fumes. The installation of engineering controls on pavers in the United States to improve the workplace environment has been a major initiative in this country, he said. But research on fumes is continuing around the world, as well. 

Increased pressure to use reclaimed asphalt pavement and other waste materials in asphaltic concrete is being experienced around the world. There's increased emphasis on asphalt emulsions techniques, and cold mixes. 

Efforts to reduce road noise -- especially though paving materials -- has accelerated worldwide, he said. "There is much more interest in noise attenuating materials such as open-graded friction courses, but there are major concerns about methods to maintain durability as well as the functional properties of open-graded friction courses," Acott told the opening session. 
 

Use the technology 

Ed Miller, president of the Asphalt Institute, challenged the registrants to use the new technologies available to them. 

Superpave is driving new technology, and the industry had better become aware of it. "The concept of Superpave is a major step forward in performance testing and specifications," he said. 

"As such it affects nearly everyone in the asphalt community. Equipment, testing methods, construction practicalities, binder production, certification, field performance are among the many areas that have been, are being or will be addressed. Numerous research projects have been completed, and even more being conducted," Miller said. "Many outside the United States are starting to get involved in Superpave." 

Localized knowledge bases and regionalism have impeded technology transfer, but this is changing as web sites are developed on the Internet. No other medium offers the same opportunity for instantaneous, worldwide knowledge and technology transfer, he said. 

Even as the communications medium has changed, though, new challenges that would attempt to halt all asphalt paving have risen. "The need exists today, more than ever, for a strong asphalt global community," Miller told the opening session. 

Threats to asphalt use abound worldwide, and are being used by enemies of road building. They will determine how asphalt will be used five years from now, he said. 

"First and foremost is the issue of asphalt fumes," Miller said. "Research has been going on for years. Many studies have been completed. The base of knowledge is growing. The issue is not over yet, and I suspect it eventually will impact everyone in this room, because environmental regulatory actions have a away of transcending international borders." 

Another issue is the U.N. global climate change treaty, which is to be approved this December in Kyoto, Japan. "The deadline is approaching fast, even as the scientific debate goes on," Miller said. "The one truth that stands out is that there is no common agreement as to whether a problem exists; and if so, to what extent, and whether anything needs to be done." 

Yet no one issue has so much potential for adversely regulating the petroleum, construction and transportation industries, Miller said. "It's the perfect example of how media hype, environmental money and politics can all combine -- with a lack of knowledge -- to influence our lives and asphalt pavements. We need to keep our eyes open on this one." 

Highway funding also is under fire from an environmental perspective, Miller said. "ISTEA was developed without the involvement of many in the transportation industry," he said. "The environment groups were able to influence the bill to divert highway funds for environmental causes." This was continuing in ongoing federal highway program reauthorization lobbying. 
 

FHWA urges research application 

Application of research in asphalt pavements was the theme of an opening presentation from the Federal Highway Administration. 

"There are three key areas of equal importance in our program: structure design, mix design and specifications development," said Paul Teng, P.E., chief of FHWA's Pavements Division. 

"The program must work toward performance-based applications, and must consider material properties," he told the opening session. "It must include rehabilitation maintenance work, as well as new construction designs." 

A century ago, evolution of asphalt pavements in the United States began with simple "recipes", Teng said, but those were refined by the work of Bruce Marshall and Francis Hveem. "For the past 50 years we have been using the procedures they have developed," he said. 

But SHRP changed all that. "With the excellent Strategic Highway Research Program, we are now trying to implement Superpave binder specifications and volumetric mix designs," Teng said. "We look forward to progressing to Superpave mixture analysis and performance analysis, to eventually moving toward a more advanced mix design series." 

In the specifications area, the FHWA is moving toward statistical quality analysis and quality control [QA/QC], Teng said. "Ultimately we are looking to performance-related specifications." 

Structurally, the United States used "rule-of-thumb" designs, Teng said. "In the 1960s we worked with the states to develop the AASHTO design equations," he said. "Now the states are working together to develop a mechanistically based design guide." This is the AASHTO 2002 Guide, which is a precursor of continuing mechanistic approaches. 

"The primary goal of FHWA's asphalt technology program is to unify and accelerate the evolution of the key areas of structure, mix design and specifications," Teng said. "We are working with the states, with industry and academia partners to develop the 2002 guide, in implementing Superpave volumetric mix designs, and the statistic QA/QC specifications. These are critical targets."