Ever since its beginnings in 1955, the National Asphalt Pavement Association (NAPA) and its members have been dedicated to the proposition that building asphalt pavements of the highest quality will, in the long run, provide the greatest value to motorists and to the public agencies that serve them. The first standing committee of the fledgling association was the Quality Improvement Committee, which is still going strong.
With the emergence of the Asphalt Pavement Alliance, quality has come to the forefront even more. This unique partnership brings together NAPA, the Asphalt Institute and the State Asphalt Pavement Associations to further the use and quality of hot-mix asphalt (HMA) pavements. The tools the alliance uses are research, technology transfer, engineering, education and innovation.
The alliance’s rapid rise is one of the most remarkable developments I have ever witnessed in any industry. Barely 18 months ago, it was just an idea. Today, the alliance is a major force uniting the asphalt pavement industry.
Our strategy is to bring together all segments of the industry at the national level to increase our body of knowledge and develop informational tools. These tools are then deployed at the local level by the state asphalt pavement associations through programs of technology transfer and education. The website (www. AsphaltAlliance.com) carries our information to all corners of the globe.
The alliance’s greatest accomplishments are the advancement of the perpetual pavement concept and the development of software for life-cycle cost analysis.
The software, which follows Federal Highway Administration procedures, allows the user to compare the life-cycle costs of any two pavement types–HMA versus portland cement concrete, conventional asphalt versus Superpave and so on. If desired, user delay costs may be included in the analysis. The software is available free on CD from the alliance at 888/468-6499 or may be downloaded from the web.
Perpetual pavement is an idea whose time has come. Recent research leads us to the conclusion that asphalt pavements can be designed as permanent structures. Under the perpetual pavement concept, total reconstruction–the remove-and-replace option–is rendered virtually obsolete. The pavement structure remains in place, while the surface layer is periodically replaced and the old pavement material is recycled. All the maintenance that will ever need to be done can be done under traffic and at off-peak hours. We can cold mill the top 2 in. of the pavement and place the new pavement overnight, and the public never needs to see an orange barrel.
Because of the inconvenience suffered by the traveling public when a failed pavement reaches the end of its design life and has to be totally reconstructed, state DOTs are attracted to the cost effectiveness and reduced traffic delays that perpetual pavements would bring about.
One thing that makes it easy for the states to embrace the concept is that it is not a new idea. We have been building full-depth and deep-strength asphalt pavements since the 1960s.
The alliance has created the Perpetual Pavement Award program to recognize pavements that have been in service for more than 35 years, have carried significant amounts of traffic and have not required maintenance beyond infrequent resurfacing.
The first recipient of the award was the New Jersey Turnpike, constructed in 1951 and still using the original pavement structure. When asked how much longer the pavement could be expected to last, the Turnpike Authority’s chief engineer said, "I don’t see why it shouldn’t last another 50 years."
Also receiving the award in 2001 were I-40 in Oklahoma and I-90 in Washington state. These three pavements–one on each coast and one squarely in the nation’s midsection–show that perpetual pavements can be constructed on any terrain, can withstand any climate and can bear up to the punishment of tremendous traffic loads.
Beyond the living examples provided by Perpetual Pavement Award winners, studies conducted on two continents offer evidence of the validity of the concept. The scholarly new document, "Perpetual Pavements: A Synthesis," just published by the alliance, brings together the experience of researchers from France, the U.K. and states across the U.S.
The paper discusses every aspect of the perpetual pavement, including design principles, construction issues, the performance of demonstrated long-life pavements and the experiences of agencies working toward the goal of long-life pavements.
