|Accelerating Infrastructure Innovations|
|Federal Highway Administration > Publications > Focus > December 2009 > Strategic, Safe, and Sustainable: Today’s Vision for Pavements|
|Publication Number: FHWA-HRT-10-009
Date: December 2009
Strategic, Safe, and Sustainable: Today’s Vision for Pavements
by Peter Stephanos
It’s all about pavements. From design and analysis to materials, construction, management, and preservation, the Federal Highway Administration (FHWA) is working with States and other partners to achieve the high-performing, safe, and cost-effective pavement network that the traveling public and the Nation’s economy depend upon every day.
FHWA’s offices of Pavement Technology, Asset Management, and Infrastructure Research and Development, and the FHWA Resource Center coordinate efforts to plan and deliver a Pavement and Materials Program that focuses on six areas:
Over the past 2 years, FHWA has conducted focused assessments of State practices and needs to identify the highest priorities in supporting State and local transportation agencies. A continuing priority is working with States as they transition to using the Mechanistic-Empirical Pavement Design Guide (MEPDG). Developed under National Cooperative Highway Research Program Project 1-37A, the Guide provides a uniform basis for the design of flexible, rigid, and composite pavements, using mechanistic-empirical approaches that more realistically characterize in-service pavements and improve the reliability of designs. Accompanying MEPDG software will be released in 2010. The software will provide a significant boost to State implementation efforts, allowing transportation agencies to more fully use the new design approach.
Other FHWA efforts to support advancement of pavement design include updates to the Falling Weight Deflectometer (FWD) calibration procedures (American Association of State Highway and Transportation Officials (AASHTO) Standard R 32), development of guidance to support using FWD data in mechanistically-based design systems, and updates to the AASHTO test for Coefficient of Thermal Expansion, now adopted as AASHTO Test Method 336.
FHWA is also planning to provide guidance in the area of pavement type selection, with a particular focus on the use of alternate bidding. FHWA’s RealCost software provides a tool to perform life cycle cost analysis that can be used to make more informed pavement selection decisions. Now available in Version 2.5, RealCost can simultaneously analyze up to six design alternatives. To download RealCost 2.5, visit www.fhwa.dot.gov/infrastructure/asstmgmt/lccasoft.cfm.
Accelerated construction is another key emphasis area. Delivering projects faster while minimizing impacts to the public and providing high quality construction has never been more critical. FHWA has worked with States to hold more than 30 Accelerated Construction Technology Transfer (ACTT) workshops across the country, helping to save millions of dollars and years of costly travel delays. To download an ACTT Workshop Toolkit or for more information on accelerated construction, visit www.fhwa.dot.gov/construction/accelerated.
Among the tools FHWA is enhancing to support construction operations is the Constructibility Analysis for Pavement Re-habilitation Strategies (CA4PRS) software. This tool can be used to identify optimum pavement construction strategies. To learn more about CA4PRS, visit www.dot.ca.gov/research/roadway/ca4prs/index.htm.
Working with transportation agencies to implement intelligent construction is also a primary emphasis for 2010, including the use of technologies such as intelligent compaction and automated sampling and testing. Compaction during the paving process is critical to achieving high-quality and uniform pavement materials and long-lasting roadway performance. Intelligent compaction uses vibratory rollers equipped with a measurement and control system that can automatically control compaction parameters in response to materials stiffness measured during the compaction process.
To further advance intelligent construction concepts, FHWA is sponsoring research and development of inexpensive wireless sensors that can be installed within highway infrastructure. These sensors are self-powered by vehicle vibrations and can store data on the roadway’s physical make-up, collect data on the real-time condition of the infrastructure, and transmit information to a data collection vehicle using radio frequency identification technology.
In 2009, FHWA assessed the current state of the practice used by State highway agencies to manage pavement networks. This assessment will help guide FHWA as it provides targeted assistance in 2010 and helps States maximize the use of their pavement networks and raise performance expectations. A new Pavement Health Track Analysis Tool will be available from FHWA in 2010, allowing users to determine and report on the health of their pavement network based on the concepts of remaining service life. The pavement health is evaluated by looking at pavement life, rideability, or distress by pavement type under various conditions, such as climate or whether it is in a rural or urban environment.
Materials quality assurance is another vital factor in raising performance expectations. For 6 years, FHWA has provided detailed week-long reviews of materials quality assurance practices at States’ request. For more information on these reviews and best practices that have been identified, visit www.fhwa.dot.gov/pavement/qa/index.cfm. Three national priority areas identified through the reviews are improved data verification, dispute resolution, and independent assurance of materials data collection. FHWA is working with its State and local partners to assist in these areas, including developing a new software tool, SpecRisk. The SpecRisk program enables users to analyze and understand risk and develop statistically valid quality assurance specifications, allowing agencies to obtain a more uniform product, better link project payment to the product received, and reward contractors for quality. To obtain a copy of SpecRisk, contact Michael Rafalowski at FHWA, 202-366-1571 (email: email@example.com).
FHWA has also developed several new test methods that agencies can use to verify specification compliance for asphalt mixtures. AASHTO Test Method TP 72-08 can be used to quantitatively determine the percentage of lime in hot mix asphalt (HMA), while AASHTO Test Method TP 78-091 can be used to test for the presence of polyphosphoric acid in asphalt binder.
As a new decade begins, environmental stewardship will become even more important. Priorities include maximizing the use of recycled highway materials in pavement construction and rehabilitation. FHWA has focused on maximizing the use of reclaimed asphalt pavement (RAP), recycled concrete as aggregate (RCCA), and asphalt shingles in high beneficial use applications. Advancing technologies to better utilize in-place recycling and the use of industrial byproducts as a highway material are also priorities for FHWA. Recent findings from FHWA’s Long Term Pavement Performance program show that RAP and virgin HMA mixes used in overlays of flexible pavements showed approximately the same performance for a range of climates, traffic conditions, and existing pavement conditions over a service life ranging up to 17 years. This finding should give State agencies confidence in specifying RAP mixtures for overlays when economic and other conditions warrant.
Since 2006, FHWA has participated in the Green Highways Partnership (GHP), a collaborative effort to encourage environmentally friendly road building that includes the U.S. Environmental Protection Agency, other Federal and State agencies, industry, trade associations, members of academia, and contractors. Current Green Highways initiatives include an effort to better align various State specifications for using recycled materials. To learn more about GHP, visit www.greenhighways.org. More information on recycling highway materials is available at www.fhwa.dot.gov/pavement/recycling/index.cfm.
Another key sustainability initiative is increasing the use of warm mix asphalt, which uses less energy than traditional HMA and generates fewer emissions, while providing a more workable mix. FHWA has held demonstration projects on warm mix asphalt and is currently developing a performance-based specification for its use. To learn more, visit www.fhwa.dot.gov/pavement/asphalt/wma.cfm.
FHWA is also conducting research targeted at greatly expanding the types and amounts of fly ash that can be used in paving concrete.
In 2010, FHWA will continue to work with the Strategic Highway Research Program (SHRP) 2 as it moves forward with developing recommended procedures, practices, and applications to advance the Nation’s highway system. For more information about SHRP 2, visit www.trb.org/SHRP2.
From the state-of-the-art research of FHWA and SHRP 2 to the on-the-ground daily emphasis on quality assurance to the sustainability promise of green highways, today’s pavement initiatives aim to advance the vision of meeting drivers’ needs while building and maintaining a safe, long lasting, and cost-effective highway system. Working with its many partners across the country, FHWA remains committed to achieving that vision and building the pavements of tomorrow today.
Peter Stephanos is the Director of FHWA’s Office of Pavement Technology. To learn more about FHWA’s pavement resources, visit www.fhwa.dot.gov/pavement.
United States Department of Transportation - Federal Highway Administration