PAVEMENT TECHNOLOGY
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Asphalt and Energy Conservation. A National Workshop on Materials and Energy Conservation for Hot-Mix Asphalt took place November 1-2, 2006, in Indianapolis. To view or download the presentations, click here.
Porous asphalt. Environmentally friendly porous pavements can conserve water, reduce runoff, promote infiltration, cleanse stormwater, protect streams, and allow for better use of land. Learn all about it here.
Warm-mix asphalt. People are talking about warm-mix asphalt, several new technologies that have the potential to lower the production and construction temperatures for asphalt by 50 to 100 degrees.
Mechanistic-Empirical Pavement Design
Pavement design has changed dramatically in the last two decades. The next change in HMA technology will be the introduction of an improved method for designing the pavement structure. A series of articles in HMAT magazine introduces the concepts of mechanistic-empirical pavement design and discusses its features.
Enhancing Value and Performance
A key mission of the National Asphalt Pavement Association is to enhance the value and performance of Hot Mix Asphalt pavements. The resources NAPA provides to the industry and our agency partners are focused on providing the highest quality HMA pavement. This commitment to quality is reflected in the concept of Perpetual Pavements.
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What is Perpetual Pavement?
A Perpetual Pavement is comprised of a thick HMA layer over a well-built foundation. It is designed to resist the most devastating forms of distress, namely bottom-up fatigue cracking and structural rutting. This ensures that costly, time-consuming pavement reconstruction is avoided, and that life-cycle costs and highway user delays are minimized.
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Developed by NAPA and published by the Asphalt Pavement Alliance (APA), the Perpetual Pavements: A Synthesis contains technical material, references to the existing literature that is relevant to Perpetual Pavements, a summary of current activities in several states plus the United Kingdom, and a valuable bibliography. It is of interest to researchers, specification writers, pavement designers, materials suppliers, and contractors. Click here for a [free download] from the APA web site.
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Materials and Mix Design
The highway user has an increased awareness of pavement quality and is now demanding more for their money. To meet this demand, the quality of HMA mixtures and pavements must continually be enhanced. NAPA offers many publications and videos to assist the industry with HMA technology. In addition, HMAT magazine provides articles that directly address issues such as mix type selection, mechanistic design, and pavement specification. Several are posted below in online resource library.
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The NAPA Guide for Hot Mix Asphalt Pavement (TAS-30) provides a wealth of information on the technology used in selecting materials, designing and testing mixtures, designing pavements, construction, pavement evaluation, and maintenance and rehabilitation. It is an excellent resource for anyone wanting to learn more about HMA. To view the Table of Contents, [ click here]. View this item on our online store. |
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MultiCool is an easy to use computer program which can be used to estimate how rapidly a newly placed asphalt mat will cool. It can be used to time late season paving and compaction operations as well as scheduling the placement of multiple lifts of HMA when construction speed is of the utmost importance. To learn more and download your free copy of MultiCool, [ click here].
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Life Cycle Cost
Life Cycle Cost Analysis is becoming the means by which pavement structures are being evaluated and eventually selected by pavement owners. The life-cycle cost of a road includes the money spent both on the initial construction of a road and maintenance over its lifetime as well as user-delay costs. Life-cycle costs of Hot Mix Asphalt pavements are significantly lower than those of portland cement concrete pavements. The Federal Highway Administration has developed a procedure which can be used to calculate Life Cycle Costs and a convenient computer program has been developed by the Asphalt Pavement Alliance using this procedure. Click here for a [free download] of the Life Cycle Cost Anaylsis software, fact sheets, and other tools from the Asphalt Pavement Alliance web site.
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Research -- The National Center For Asphalt Technology
In 1986, NAPA Members, working through the NAPA Research and Education Foundation, endowed the National Center for Asphalt Technology (NCAT) at Auburn University. NCAT is the world’s most celebrated asphalt research institution. Today, it is the home of the 1.7-mile test track, a banked oval that is being used to test a variety of asphalt mixes. Heavier-than-normal trucks, traveling at a constant 45 mph, will yield 10 to 12 years’ worth of data in a two-year period. Visit NCAT for more information on the test track and other research.
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NCAT has significantly contributed to the progress of technology in Hot Mix Asphalt throughout its existence. In 1991 NCAT developed the premier textbook for university instruction on Hot Mix Asphalt, Hot Mix Asphalt Materials, Mixture Design, and Construction. Now in its second edition, it is also an excellent reference book for anyone wanting to know more about asphalt technology. To learn more and/or order a copy of the textbook, [ click here].
The NCAT oven for rapidly determining asphalt content without using solvents has become a widely used test method. It's guidance on the use of mixture volumetrics in the control of HMA production is frequently referenced by agencies and contractors alike. The success of the Professor Training Program in providing instructional tools and information to 300 college professors and other trainers ensures that future generations of highway engineers will be versed in HMA technology. Many of NCAT's publications may be downloaded for free at its web site.
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Online HMA Resource Library
NAPA offers the following items free to individuals in the Hot Mix Asphalt pavement industry. They are available for online viewing or downloading. Additional copies of reports, publications, and articles are available to NAPA Members on the members-only section of this web siite. For more information on how to become a Member and take advantage of the Members Library as well as many other opportunities, visit Join NAPA.
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- Rutting--Leave it to the Deer!, HMAT article [Click Here]
- Mechanistic Design, HMAT article series [Click Here]
- Statistical Specifications, HMAT article series [Click Here]
- Recycled Foundry Sand, HMAT article series [Click Here]
- Hot Mix Asphalt Visions 2000 and Beyond [Click Here]
- Lies, Damned Lies, and Traffic Forecasting [Click Here]
- Wanted: Transfer Functions - Experience Needed! [Click Here]
Links to Additional Resources
For links to other web sites, including state associations, government agencies, and associations, [click here].
HMA Personnel Skill Sets Assessment
 NAPA's new tool for workforce development in the areas of HMA production, QC/QA, HMA placement, and management. These skill sets were developed and reviewed by NAPA’s QIC Education Subcommittee.
View Skills Assessments Page
Recycled Foundry Sand
This is a two-part series appearing in HMAT magzine, discussing Recycling Foundry Sand.
Author: Chuck Hughes, P.E.
Article 1: Sources and Properties
Article 2: In the Mix
For more questions about pavement technology, please e-mail the engineering department.
PRACTICAL PAVING NEWSLETTER
Practical Paving is NAPA's newsletter for paving contractors
specializing in city streets, commercial work, and driveways.
 Issue 03, February 2007
 Issue 02, January 2006
 Issue 01, October 2005
Please contact Chuck MacDonald at NAPA
for additional hard copies of this publication.
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