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Federal Highway Administration Research and Technology
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This magazine is an archived publication and may contain dated technical, contact, and link information.
|Publication Number: Date: January/February 2000|
Issue No: Vol. 63 No. 4
Date: January/February 2000
As we enter the new millennium, the demands on our highway network and available transportation funding are greater than ever. These demands, combined with growing, public expectations for safety, quality, and performance, require highway agencies to maintain the highest level of service practical. To meet these demands, highway agencies are redefining their objectives, requiring them to focus on preserving and maintaining rather than expanding our existing highway system. We are working to make the system work better, run more smoothly, and last longer.
The nearly 70,000 kilometers of the Dwight D. Eisenhower National System of Interstate and Defense Highways, also known as the Interstate Highway System, cost more than $129 billion to construct. The cost of the interstate highways and the cost to construct and maintain the more than 6 million kilometers of state and local roadways represent one of the nation's largest infrastructure investments in our country's history. Roads and streets are just that -- an investment.
The 1997 report to Congress titled Status of the Nation's Surface Transportation System: Condition and Performance declared that the pavement for approximately 48.7 percent of our rural interstate mileage and almost 60 percent of our urban interstate mileage is rated in fair to poor condition. From these percentages, it is evident that the pavement condition of our nation's highway infrastructure is deteriorating.
The financial demands on highway agencies to repair the damage is greater than ever and will continue to grow unless we can better control the rate of deterioration. To maintain high-quality pavements and to remain within budgetary limits, a change in philosophy from the traditional reactive maintenance approach to a preventive approach must be made. The preventive approach is represented by the concept of pavement preservation, which seeks to make sure that reconstructed, rehabilitated, and existing good pavements last longer, stretching available funding further. If accomplishing this seems like a challenge, that's because it is, but it can be done.
If we delay maintenance and repair of pavement until it has gone beyond its effective service life, the work required to renew it will be more extensive and costly than regular maintenance. Also, the repair work will make a portion of the highway unusable, and the flow of traffic will be disrupted for an extended period of time.
However, if we take a proactive approach in maintaining our existing highways, we can reduce costly, time-consuming rehabilitation and reconstruction and the associated traffic disruptions. With timely preservation, we can provide the traveling public with improved mobility; reduced congestion; and safer, smoother, longer lasting pavements. This is the true goal of pavement preservation -- a goal that the Federal Highway Administration (FHWA), working in partnership with states, industry organizations, and other interested stakeholders, is committed to achieving.
What Is Pavement Preservation?
As a component of system preservation, pavement preservation is aimed at preserving the investment in our highway system, extending pavement life, and meeting our customers' needs. It is the timely application of carefully selected surface treatments to maintain or extend a pavement's effective service life. Pavement preservation does not include new or reconstructed pavements or any activity that significantly increases the structural capacity of the existing pavement. Figure 1 shows the general concept behind pavement preservation.
An effective pavement-preservation program encompasses a full range of preventive maintenance techniques and strategies, such as fog seals, slurry seals, chip seals, micro-surfacing, thin lift overlays, crack sealing, portland cement concrete (PCC) joint sealing, dowel-bar retrofit, full- and partial-depth concrete pavement repair, and milling and grinding.
A traditional rehabilitative approach allows the original pavement section to deteriorate to a fair to poor condition in terms of both ride quality and structural condition. At this point, structural damage has occurred, and the objective of the rehabilitative treatment is to repair that damage and restore the pavement. Thus, the traditional approach is reactive and can be a costly and time-consuming process.
A preservative or proactive approach entails the application of a series of low-cost, preventive maintenance treatments that individually last for a few years. The key is to apply the treatment when the pavement is still in relatively good condition with no structural damage. (Once structural damage occurs, a preventive maintenance treatment is no longer a viable option.) Timely preventive maintenance treatments will significantly reduce traffic delays.
The end result is an extension of the service life of the original pavement, and extending the service life instead of having to rehabilitate the pavement translates into a savings in funds and a better overall ride quality. It is important to realize that no pavement lasts forever, and pavement-preservation activities do not prevent a pavement from eventually deteriorating. They are intended to reduce the rate of deterioration and to make highway maintenance more cost-effective.
For a successful pavement-preservation program, a long-term commitment and financial support from management is required. Pavement preservation is more than just a collective set of specific pavement-maintenance techniques. It is a way of thinking and the guiding force behind an agency's financial planning.
Implementing the Pavement-Preservation Philosophy
A major hurdle in establishing a pavement-preservation program is dedicated funding. In many highway agency budgets, maintenance activities have traditionally received "bottom of the barrel" funding. In addition, because most maintenance budgets cover the cost of activities such as snow and ice removal, a harsh winter can severely impair an agency from funding its reactive maintenance needs -- let alone having money for preservation.
So, from where will these dedicated funds come? That funding is the responsibility of lawmakers, budgetary planners, and upper level management. However, these individuals, along with the public, need to be convinced that every dollar spent now on pavement preservation can save up to six dollars in the future. Therein lies the importance of a comprehensive training program in conjunction with champions who are committed to fostering the success of pavement-preservation programs and techniques.
|When a highway is this badly deteriorated, preventive maintenance is no longer a viable option.|
The good news is that these efforts are underway, and they are making a difference. In 1997, an expert task group (ETG) with members from the American Association of State Highway and Transportation Officials (AASHTO), industry, and FHWA was established to provide guidance and technical assistance in the area of pavement preservation. This ETG provides technical advice and review on such things as training materials, courses, and research activities.
In July 1997, FHWA, AASHTO, and several industrial organizations signed a formal letter of understanding that committed industry and FHWA to jointly fund the development of short courses on pavement preservation and other mutual research interests. This is the first time industry has put up equal funding to develop this type of training program.
The National Highway Institute (NHI) is developing a comprehensive pavement-preservation training program of at least four courses.
The initial course is "Pavement Preservation: The Preventive Maintenance Concept" (NHI course #13154). This 16-hour course addresses policy issues, funding strategies, and pavement-maintenance technologies. It emphasizes the need for and the benefits of an effective pavement-preservation program.
The second course, "Pavement Preservation: Selecting Pavements for Preventive Maintenance" (NHI course #13158), is currently being developed and will illustrate in detail the project selection and evaluation, materials consideration, and construction operations necessary for quality pavement-preservation treatments.
|When a highway must be reconstructed, congestion and travel delays are often the consequences.|
The AASHTO Lead States Team on Pavement Preservation has been promoting the philosophy of pavement preservation among state departments of transportation (DOTs) and other related agencies for the past three years. The AASHTO Lead States Team, in association with the Pavement-Preservation ETG and the Foundation for Pavement Preservation (FP2), developed a "Protecting Our Pavements" video featuring DOT officials from Georgia, Kansas, Michigan, and Pennsylvania and a former director of FHWA's Office of Engineering.
The video discusses the importance of pavement preservation and is the first in a series of videos aimed at educating both upper management and field personnel. A second video, which is scheduled to be released in early 2000, focuses on selecting the proper pavement for pavement-preservation activities. Future video topics include construction and design techniques for various pavement-preservation treatments and the incorporation of pavement preservation into a pavement management system.
The Lead States Team also recently developed research protocols for pavement preservation. The importance of accurate and reliable information cannot be overlooked. This information, when combined with life-cycle cost analysis (LCCA), is needed to make informed ecisions and to demonstrate the effectiveness and economics of pavement preservation. The research protocols were established to serve as guidelines in performing research related to pavement preservation to ensure the generation of clear, concise, and comprehensive research data necessary to demonstrate the proper implementation of pavement-preservation activities.
|An effective pavement-preservation program encompasses a full range of preventative maintenance techniques and strategies, such as fog seals, slurry seals chip seals, micro-surfacing, thin lift overlays, crack sealing, portland cement concrete (PCC) joint sealing, dowel-bar retrofit, full- and partial-depth concrete pavement rapair, and milling and grinding.|
To identify roadblocks, barriers, and obstacles for future improvements in pavement preservation, AASHTO, FHWA, and FP2 conducted a "Forum for the Future" in Kansas City, Mo., in October 1998. Approximately 120 stakeholders from 32 states and Canada attended the forum. They brainstormed for ways to meet challenges in the areas of management, marketing, local government, research, training, and data management. The result of this forum was the development of a "road map" that outlines action items required to address the challenges identified by the forum participants. The information contained in the road map will serve as the Lead States Team's recommendations to the AASHTO Subcommittee on Maintenance and as part of the Lead States Team's transition plan.
The results of all of these efforts have been an increased awareness of and dedication to pavement preservation within highway agencies and industry. Several states are considering or establishing a formalized pavement-preservation program and are using dedicated funding to support such initiatives.
While the concept of and techniques for pavement preservation are universal, the actions required to successfully implement a pavement-preservation program are regionally dependent. Each highway agency needs to establish its own protocols, strategies, and methodologies to produce the desired return on investment.
Experiences With Pavement Preservation
The potential benefits of a successful pavement-preservation program can be numerous. A 1997 AASHTO lead-state survey of state highway agencies showed that most highway agencies are convinced of the advantages associated with a properly designed and implemented pavement-preservation program. The anticipated benefits from such a program can include higher customer satisfaction, increased safety, cost savings/cost-effectiveness, improved pavement condition, improved strategies and techniques, and better informed decisions.
The states with the most experience in successfully implementing a pavement-preservation program include California, Georgia, Michigan, New York, and Texas. Georgia and Texas, which have been performing preventive maintenance on their roadways for several years, report that their pavement-preservation programs have played a substantial role in improving the condition of their highway infrastructure.
In its 1997 summary of pavement conditions, the city of Bedford, Texas, documented that the cost of preventive maintenance treatments is much less than the cost of rehabilitation or reconstruction. Therefore, the city recommended the timely use of these treatments rather than waiting until rehabilitation or reconstruction was needed.
Georgia reported that the effects of reallocating funds from rehabilitation and reconstruction to pavement preservation have been minor. Georgia found that very few major projects were delayed while the state addressed the larger number of lower cost pavement-preservation projects.
|Figure 1 — Applying pavement treatments at the optimal time provides the most efficient use of funds to extend the life of the pavement.|
California, Michigan, and New York more recently implemented a pavement-preservation (preventive maintenance) program. In these three states, the decision to implement a pavement-preservation program followed an analysis that determined that pavement preservation was the most cost-effective means to achieve long-term, pavement goals. As part of their implementation process, these states identified pavement-related, preventive maintenance treatments that worked successfully in their states. For these treatments, they identified the pavement conditions, expected service life of the treatment, and its estimated cost.
Michigan notes that rehabilitation and reconstruction projects cost about 14 times as much as preventive maintenance projects per lane-mile. By implementing a preventive maintenance program, Michigan has enjoyed a cost savings of more than $700 million since 1992 (based on what would have been needed for more major programs if the network had been allowed to deteriorate).
Caltrans (California Department of Transportation) in a workshop presented to the California Transportation Commission, notes that preventive maintenance treatments can restore a pavement surface and "extend its service life by 5 to 7 years. ... This added service life will delay the need for the more costly pavement rehabilitation, allowing additional rehabilitation projects to be funded and constructed."
New York's experiences have shown that a dedicated fund with money set aside for pavement-preservation activities is highly beneficial and that support from upper level management is crucial in obtaining those funds. New York also notes that selling the preservation program is a continuing effort because legislators and executives change.
A common observance among all of these states is the relatively long length of time for the benefits of pavement preservation to be realized in terms of improved pavement condition. Georgia and Texas, who have had a preservation program in place for many years now, have anecdotal evidence of the benefits. New York, whose preservation program was established in 1993, is beginning to observe the results in their annual pavement condition survey.
The Road Ahead
In addition to establishing a pavement-preservation philosophy, other issues must be addressed to ensure the proper implementation of a pavement-preservation program. The success of a pavement-preservation program is based on selecting the right treatment for the right pavement at the right time. The real challenge lies in selecting the optimal time to apply a treatment to the road.
Time is the element by which cost-effectiveness is defined. Placing a treatment on the road too late, meaning structural damage has already started to appear, will result in poor performance because pavement-preservation treatments are not designed to increase structural capacity. On the other hand, placing the treatment too early will result in the unnecessary expenditure of much-needed funds and can cause other pavement problems, such as flushing or rutting. Neither scenario is cost-effective. The optimal time will maximize the return on investment of a given treatment by allowing for the most efficient use of funding to extend the life of the pavement.
To determine the optimal timing, performance standards and indices for various treatment types need to be established through research and the collection of performance data. To be reliable, these indices must be descriptive of the environment in which the pavement treatments are to be used. This not only includes existing pavement conditions, climatic weather, material properties, and traffic loading, but also agency resources and funding limitations.
Another issue is the emergence of performance-related specifications (PRS) and associated performance-level warrantees. In the future, pavement contractors may be required to guarantee the performance of a pavement for a specified service life. To ensure this level of performance, the contractor will be responsible for performing maintenance or preservation activities on an elective basis. It is critical that the concepts and techniques of pavement preservation are passed on to the contractor to ensure that maintenance is preventive rather than reactive. Therefore, pavement contractors must be part of the target audience.
And finally, we must integrate pavement preservation into the overall pavement management system (PMS) to allow highway officials to manage pavement conditions as part of managing their resource allocations. PMS provides critical information needed to make decisions about pavement preservation. By using an integrated PMS, a manager can select the proper proportion of preventive maintenance, corrective maintenance, rehabilitation, and reconstruction that optimizes available dollars and extends the service life of the pavements within the system.
FHWA and its partners will continue to make strides to identify the important factors in a successful pavement-preservation program and to provide the necessary tools to make cost-effective decisions. Pavement preservation is the key to our highway's future, and together, we can ensure its success and benefit from its rewards as we preserve one of our nation's largest investments.
For more information about pavement preservation, contact Robert Davies via telephone at (202) 366-2023, fax at (202) 366-9981, or e-mail at email@example.com.
Defining the Concept
Promoting the concept of pavement preservation requires that everyone, including the promoters, have a clear understanding about what pavement preservation is and about how it relates to existing maintenance activities. A major problem is that a consensus has not been met on the definitions of pavement preservation, preventive maintenance, and pavement maintenance. Through the recent efforts of the American Association of State Highway and Transportation Officials (AASHTO) Lead States Team on Pavement Preservation, industry representatives, and FHWA, an attempt has been made to clarify the relationship between preservation and maintenance.
Pavement preservation is the sum of all activities undertaken to provide and maintain serviceable roadways, including preserving investment in the national highway system, extending pavement life, enhancing pavement performance, ensuring cost-effectiveness, and reducing user delays. Pavement preservation includes preventive maintenance and minor rehabilitative activities. Pavement preservation is a component of system preservation.
Pavement preservation does not include new pavement, reconstructed pavement, or pavement requiring major rehabilitation or reconstruction.
Preventive maintenance for pavement is a tool for pavement preservation. It is a strategy to apply cost-effective treatments to the surface of a structurally sound pavement to preserve the system, retard future deterioration, and maintain or improve the functional condition of the system without increasing its structural capacity.
Pavement maintenance includes three forms of maintenance activities: preventive, routine, and reactive (corrective) maintenance. Preventive maintenance is defined above. Routine maintenance is day-to-day activities, such as crack sealing, line stripping, mowing, and cleaning roadsides. These activities are scheduled, and the scheduling is within the control of maintenance personnel. Reactive maintenance is activities that must be done in response to events beyond the control of highway agencies. These activities include pothole patching, repairing pavement blowups, snow and ice removal, and unplugging drainage facilities. Activities, such as major pavement rehabilitation and pavement reconstruction, that significantly affect the structural capacity of the pavement are considered capital improvements and not maintenance.
Desired Outcomes Necessary for Pavement-Preservation Implementation*
*Defined by the 1998 Forum for the Future in Kansas City, Mo.
Robert M. Davies is a construction and preservation engineer in FHWA's Office of Asset Management. He serves as the lead in the areas of system preservation and environmental concerns for construction and preservation operations. He is also the FHWA liaison to the Research Task Force of the AASHTO Subcommittee on Maintenance, is a member of the AASHTO Lead States Team on Pavement Preservation, and works closely with highway agencies and industry on the development of system preservation initiatives. Davies joined FHWA in 1996 following service as a civilian with the Department of the Navy. Before assuming his current position in 1999, his career within FHWA included assignments in the Office of Infrastructure Research and Development as a member of the Asphalt Pavement Research Team and with the Long Term Pavement Performance (LTPP) Team. He has a bachelor's and a master's degree in civil engineering from Pennsylvania State University.
Jim Sorenson is a senior construction and preservation engineer in FHWA's Office of Asset Management. He is the team leader for construction and system preservation.