Today’s pavements cost more, but they’re lasting longer with less impact on the environment; agencies, road users are enduring the costs of success. 

Government owning road agencies and their taxpaying road patrons are proving they are willing to pay the costs of success in building durable, long-lived roadways.

In an earlier day, this costly directional interchange would have been a simple cloverleaf.

From coast-to-coast, the strategic emphasis is shifting from placement of as many lane-miles as possible under budget restrictions, to careful reconstruction of existing highways — or new greenfield pavements — using carefully chosen materials, value-added proprietary products, and innovative new designs that may have been imported from overseas. And it’s being done at a price premium, even as the social and environmental mitigation costs of highway construction are added to the design.

That’s a sea change from the former paradigm, in which states were compelled by federal law to build Interstate highways — which absorbed the bulk of highway construction for four decades — as fast as possible, with relatively thin sections, placing as much concrete or asphalt as possible, mile after mile.

Today, hot-mix asphalt perpetual pavements and portland cement concrete pavements serving 50 years or longer are models created by the respective materials interests to guide construction of the premium pavements of the future.

PerRoad is a mechanistic-based procedure for the design of deep asphalt long-life or perpetual pavement structures. The latest version, PerRoad 3.2, was released in December 2006 and can be downloaded for free; see For More Information panel.

The Federal Highway Administration is supporting this effort with its Highways for LIFE program, earlier slowly growing, but now gathering momentum as the program begins to support field implementation.

The FHWA also continues to support external technology scanning tours which look beyond this country’s borders to view and import technologies that can save highway users, builders, and owners time and money, or do something that was not previously possible.

And the private sector materials industries are putting big bucks behind research on their own products. The asphalt industry early-on set the pace with the underwriting of the National Center for Asphalt Technology at Auburn University, funded by the National Asphalt Pavement Association Research and Education Foundation in 1986. The aggregates industry followed with the creation of the International Center for Aggregates Research as a joint operation of The University of Texas at Austin and Texas A&M University in 1992.

Iowa’s Concrete Pavement Tech Center’s Mobile Concrete Research Lab brings high-tech concrete materials and concrete pavement testing capabilities to the field. The 44-foot-long trailer was custom-built and is fully outfitted with equipment capable of performing a comprehensive suite of tests.

The concrete industry created the Center for Portland Cement Concrete Pavement Technology in 2000 through the support of the Iowa Department of Transportation and the Iowa Concrete Paving Association, but in 2005, the center was relaunched as the National Concrete Pavement Technology Center with the support of the American Concrete Pavement Association. Finally, pavement preservation interests — who want to see more of the states’ limited road funds go to preservation of existing pavements, rather than costly construction and reconstruction — started the National Center for Pavement Preservation at Michigan State University at Lansing in 2003.

And the underlying theme of all these efforts is the optimization of all the elements that go into construction of a pavement, from structural design, to material selection, to construction techniques, and later, timing of maintenance.

Feds reverse course

The FHWA’s Highways for LIFE pilot program is intended to accelerate the adoption of road- and bridge-building innovations and new technologies, improving safety and highway quality, while reducing congestion caused by construction. It’s publicizing its success stories to expand the awareness of, and inform the staffs of the FHWA, state DOTs, and the private sector, why it’s beneficial to pursue non-traditional approaches and technologies.

This is a major change from previous practice, and it’s important to note that a major goal of Highways for LIFE is to change the attitudes of FHWA staff itself. That’s significant because the agency still bears the traditions of the Interstate construction era, where states were forced to spend federal funds on mileage placed, not durability or longevity.

Today, Highways for LIFE consolidates hot-button technologies such as prefabricated systems, innovative contracting, design-build, and accelerated construction techniques, such as full road closure, demonstrating that complete shutdown of an artery for reconstruction hurts users temporarily but benefits them in the long run by shorter overall project duration, significantly lower project costs, smoother pavements, and elimination of work-zone dangers to workers and motorists.

In the early days of the Interstate, I-29 is opened to traffic in northwest Missouri.

But Highways for LIFE is doing more than repackaging existing technologies. It’s underwriting demonstration projects, such as those in Arizona, Georgia, Maine, Missouri, Oregon, and Virginia announced this June.

“These seven projects were selected because they serve as shining examples of what is possible with respect to improving safety and user satisfaction, minimizing construction-related congestion, and achieving high-quality, long-lasting highway infrastructure with an emphasis on highway safety and congestion relief,” said King Gee, FHWA associate administrator for infrastructure. “They will demonstrate a broad array of technologies, techniques, and approaches to achieving safe, high-quality and long-lasting infrastructure, while minimizing construction-related congestion and a higher user satisfaction rating.”

Construction costs skyrocket

While Highways for LIFE attempts to provide more product at a lower cost, an overarching theme is that it’s also okay to spend more money up front to get a longer-lasting, faster-built pavement. As such, it is just one more spur to the general trend of more costly highway construction since the Interstate era.

It’s hard to believe, but most of Highways for LIFE’s themes — such as spending more for longer-term performance, contractor design and warranties, and contractor-certified quality acceptance — were either strongly discouraged, or downright illegal under the initial rules of the Interstate system, after 1956.

Congress meant for the 42,000-mile Interstate system to have been completed by 1975, only 19 years. The early federal emphasis was on laying down as much highway as possible. Maintenance was to be the complete responsibility of the states, and states could not enhance or optimize pavement designs to reduce future maintenance responsibilities. As federal-aid funds were not to be used for state maintenance activities, over design by the states was opposed by the feds because it ultimately reduced states’ maintenance costs, thus federal funds would have been used indirectly for maintenance.

Highways for LIFE targets: right, congestion; and below, motorist and student highway safety.


The Intermodal Surface Transportation Efficiency Act of 1991 marked the end of the Interstate era, and material prices have risen dramatically since then.

For example, the Oregon DOT has tracked costs of highway elements and provides a capitulation of cost increases from 1987 through the second quarter of 2007. In Oregon, the aggregate price of excavation, crushed stone, portland cement concrete, and asphalt mixes rose 228% from 1987 to the first quarter 2007, and steel and concrete for structures rose 284.5% in the same period, ending with an aggregate 250% increase through first quarter 2007, and 278% increase through the second quarter.

The California Department of Transportation provides an earlier perspective. For selected highway construction items in that state, their costs nearly tripled from 1972 through 1987. That 1987 index then trebled again through the fourth quarter 2006, with the cost index leaping by another 30% from the fourth quarter 2006 to the second quarter 2007.

The growth in California contract prices — unadjusted for inflation — is just as arresting. From 1972 to the second quarter 2007, prices of construction aggregates to Caltrans rose from $3.21 to $27.30/ short ton, hot-mix asphalt from $8.22 to $91.46/short ton, with portland cement concrete even more extravagant, from $19.23 to $223.54/cubic yard, each just below or above a tenfold increase. As a dollar in 1972 would be $4.81 in 2006, just below a fourfold increase, it’s clear that highway construction materials have risen dramatically in real dollars in the interim.

Durable, long-lived high-performance concrete pavement is placed on Michigan''s I-75.

A big spur to the cost of building a highway appeared in January 1994, when President Bill Clinton signed Executive Order 12893, Principles for Federal Infrastructure Investments, requiring that federal infrastructure investment and management plans consider public and private, market and non-market benefits and costs. In addition to construction, maintenance, and operations costs, now social, economic, and environmental costs associated with highway construction and operation that fell outside the owning agency had to be considered in highway investment and management decisions. Those social costs included congestion, air pollution, noise, and vehicle crash costs. The net result was a diversion of surface transportation funds from construction and maintenance to non-transportation needs.

Today, high-level pavements, on average, cost a small fortune. In 2005, the Washington State DOT estimated that the cost of 1 mile of highway varied widely, considering factors such as land costs, people or businesses to relocate, environmental needs arising from construction such as noise barriers and storm water treatment for streams and wetlands, and whether new bridges or interchanges were included.

WsDOT found that widening S.R. 18 in rural King County cost about $24.5 million per mile, while U.S. 12 widening south of the Tri Cities was only $3.7 million per mile. Urban I-5 widening in Vancouver cost about $20.2 million per mile, while I-90 truck climbing lanes east of Cle Elum and at Vantage cost about $1 million per mile, all in 2005. I-5 HOV lanes cost about $7 million per mile.

Compare that to the FHWA’s 1996 estimate of the aggregate costs of the Interstate system. In 1996 dollars, the FHWA calculated the “weighted rural and urban combined” costs per mile of Interstate highway to be $20.6 million, with the cost per rural mile at $9.84 million, and the cost per urban mile at $44.13 million.

Optimize designs for best value

With those kinds of expenditures at stake, all camps of the highway design community are emphasizing the need to optimize pavement designs to get the best value for dollar expended, and if that means spending a little more upfront, well then so be it.

The perpetual pavement concept — an optimized asphalt structural design — was launched in 2002 by the Asphalt Pavement Alliance in a joint promotional effort with the Asphalt Institute, the National Asphalt Pavement Association, and the State Asphalt Pavement Associations, representing local contractor associations in 36 states.

A perpetual pavement is defined by the APA as an HMA pavement designed and built to last longer than 50 years without requiring major structural rehabilitation or reconstruction, and needing only periodic surface renewal in response to distresses confined to the top of the pavement.

Perpetual pavements are designed with thick layers of asphalt of different mix formats, with a sacrificial driving course on top. This driving or friction course is intended to be periodically cold-milled and overlaid with more HMA to restore condition.

Today’s perpetual pavement design is a three-layer hot-mix asphalt pavement that is intended to provide pavement life spans of 50 years or more, with occasional asphalt overlays to maintain optimum rideability. The layers are constructed of different asphalt designs. They are topped with a sacrificial friction course intended to be cold-milled and overlaid with asphalt at 15 to 20 year intervals to restore driveability. In practice, the actual composition and depth of the sections will vary according to anticipated conditions and traffic loads, including the percent of truck traffic.

To assist the paving community in designing perpetual pavements, the APA has rolled out a free, updated version of its perpetual pavement design software. Per Road 3.2, released in December 2006, is a mechanistic-based procedure for the design of flexible long-life or perpetual pavement structures. Developed at NCAT in conjunction with the APA, the design software uses layered elastic theory to compute critical pavement responses under various axle loads.

Within the Structure input screen, the designer may define the number of pavement layers, seasonal information, layer module, layer thickness, input variability, and perpetual pavement performance criteria. The traffic loadings and axle loadings are entered, or alternatively, default load spectra corresponding to various FHWA route classifications may be accessed and loaded directly into the program.

The APA also promotes perpetual pavements via its annual awards program. In May, the APA announced the winners of its 2006 awards, to owners of asphalt pavements that are at least 35 years old and have never had a structural failure. The average interval between resurfacing of each winning pavement must be no less than 13 years. The road must demonstrate qualities to be expected from long-life asphalt pavements: excellence in design, quality in construction, and value to the traveling public.

The 2006 winners, as determined by NCAT and validated by a panel of industry experts, are:

-Caltrans, for a section of the San Diego Freeway (I-405) between Harbor and Beach Blvds.
-Minnesota DOT for TH-61 between Wabasha and Kellogg.
-Montana DOT for a 10-mile stretch of I-90 over Homestake Pass.
-Nebraska Department of Roads for a 5-mile section of S.R. 35 in Wayne County.
-Tennessee DOT for a 14-mile section of S.R.14 in Tipton County.
-Virginia DOT for a 6.5-mile portion of I-81 in Frederick County.

Milestones on the Concrete Road Map

In the meantime, in 2006 and in response to competitive programs, the concrete industry consolidated and released its Concrete Pavement Road Map. Today, the Road Map is bearing fruit, and products are being released to the industry to help agencies and contractors build optimized concrete pavements that will be long-lived and durable under heavy loads.

This Road Map is a comprehensive and strategic plan for concrete pavement research that will guide the investment of approximately $250 million over a 10-year period.

High-performance concrete pavement, mix, and structure optimized for long life, is placed on I-75 in Michigan.

At the same time, the National Concrete Pavement Technology Center was established at Iowa State University at Ames and is aiding and coordinating research and technology transfer taking place across the country, including that driven by the Road Map.

Concrete’s Road Map combines more than 250 research problem statements from state, local, federal, and private sector stakeholders into 12 fully integrated, sequential, and cohesive tracks of research which is hoped will lead to specific products that will dramatically affect the way concrete pavements are designed and constructed. The 12 tracks are:     

-Performance-Based Concrete Pavement Mix Design System.
-Performance-Based Design Guide for New and Rehabilitated Concrete Pavements.
-High-Speed Nondestructive Testing and Intelligent Construction Systems.
-Optimized Surface Characteristics for Safe, Quiet, and Smooth Concrete Pavements.
-Equipment Automation and Advancements.
-Innovative Concrete Pavement Joint Design, Materials, and Construction.
-High-Speed Concrete Pavement Rehabilitation and Construction.
-Long Life Concrete Pavements.
-Concrete Pavement Accelerated and Long-Term Data Collection.
-Concrete Pavement Performance.
-Concrete Pavement Business Systems and Economics.
-Advanced Concrete Pavement Materials.

An early fruit of this effort is the new Integrated Materials and Construction Practices for Concrete Pavement: A State-of-the-Practice Manual, developed by the National Center for Concrete Pavement Technology at Iowa State University.

The manual is a reference for the design and construction of concrete pavements, with an eye to optimization of the pavement’s performance for long life and durability. According to the authors, the key to optimization of concrete pavements is the recognition that concrete is the central component of a complex, integrated pavement system. It’s a training tool and a reference for design engineers, QC/QA personnel, specifiers, contractors, suppliers, technicians, and laborers bridge the gap between recent research and practice regarding optimizing the performance of concrete for pavements.

Two-lift optimized pavements

This year and next, the FHWA is directing big bucks toward field testing of two-lift concrete paving, according to a disclosure at the 86th annual meeting of the Transportation Research Board in Washington, D.C., in January. The industry is looking at field demonstrations of two-lift concrete paving technology in 11 states — California, Florida, Georgia, Indiana, Kansas, Michigan, Minnesota, Oklahoma, Pennsylvania, Texas, and Washington — following a 2006 International Technology Scanning Tour on Long Life Concrete Pavements.

“There can be variations in what each state does,” said Suneel Vanikar, P.E., Concrete Group Leader, Office of Pavement Technology, FHWA.

“We have been fortunate enough to work a deal with our Highways for LIFE folks so they have agreed in principle that these projects can be funded by the FHWA,” Vanikar told Better Roads. “We are making sure states take advantage of the opportunity. For example, it could become a state’s Highways for LIFE project. We want to get something on the ground in the next couple of years, and want to move very fast.”

Two-lift construction involves the placement of two wet-on-wet layers, or bonding wet to dry layers of concrete, instead of the homogenous single layer commonly placed in concrete paving.

The middle layer of asphalt perpetual pavement structure on I-77 in Ohio is compacted with a pneumatic roller.

With two-lift paving, a thick bottom layer contains aggregate of lesser quality, lower durability or strength, locally available aggregate, or even recycled aggregate composed of asphalt or concrete rubble. A thin top layer consists of high-quality aggregate, perhaps non-locally sourced, designed to provide superior resistance to freeze-thaw damage as well as noise reduction and/or improved traction.

Simultaneously, the asphalt industry is looking at two-lift designs of its own.

While two-lift paving is not new to the United States, today’s emphasis is unprecedented. Between 1950 and 1970, two-lift paving was implemented extensively in many states, including Iowa, Wisconsin, Michigan, Pennsylvania, and Minnesota, to facilitate placement of mesh in Interstate highway construction. But between 1970 and 2000, the U.S. concrete paving industry moved away from a mesh pavement design and significantly shortened the design length of pavement panels, effectively eliminating the need for two-lift paving.

Following the May 2006 international tour, however, interest in two-lift paving was revived. The goal of the long-life concrete pavement scan tour was to learn more about design philosophies, materials requirements, construction practices, and maintenance strategies involved in constructing and managing portland cement concrete pavements with long-life expectancies.

Sponsored by the FHWA, the American Association of State Highway and Transportation Officials, and the Transportation Research Board’s National Cooperative Highway Research Program, the scan team included representatives from state transportation departments, the FHWA, NCHRP, academia, and industry associations.

Utah: Preservation optimizes expenditures

Years after optimized construction, it’s incumbent on pavement owners to optimize and fine-tune their maintenance activities to preserve their pavements.

Today’s pavement preservation techniques offer the best value for maintenance expenditures. The Utah DOT Office of Research investigated just that in a new study, Good Roads Cost Less: Updated Study. The updated study once again concluded that preserved pavements do indeed cost less in the long run, and as stewards of the public infrastructure, the Utah DOT must maintain the highway network in good condition to minimize the impacts on the citizens of the state.

Utah stated for such highways there are agency costs, primarily maintenance at different condition levels; user costs, such as annual fuel costs, wear and tear on the vehicle, and wear and tear on the tires, depending on the condition of the roadway; safety costs, with good condition pavements contributing to lower accident rates across Utah; and delay costs, the aggregate of all vehicles taken into consideration. These delay costs have an impact on the timing of preservation and rehabilitation projects as well as system expansion projects.

The Utah DOT found that preservation and rehab dollars that could be diverted away from the maintenance program to fund capacity improvements would not significantly impact capacity throughout the Utah DOT network, but would have a significant impact on the highway network condition and its maintenance and rehabilitation needs in the future and on the user costs, accident costs, and delay costs.