Pavement Preservation Scanning Tour Status Report (7/2002)

Background

Traditionally, highway agencies have allowed the ride quality and structural condition of their pavements to deteriorate to fair or poor condition before taking steps to rehabilitate the pavements. The aim of rehabilitation is to repair structural damage and restore measurable pavement conditions such as ride, rutting and cracking. This is a costly and time consuming activity with associated traffic disruptions and inconvenience to adjacent businesses and residences. In recent years, an increasing number of highway agencies have found that applying a series of low-cost pavement preservation treatments can extend the service lives of their pavements. This translates into a better investment and increased customer satisfaction and support.

France, South Africa and Australia were identified as nations that have innovative programs as well as new treatments for pavement preservation.

Goal

The goal of this scanning tour was to review and document innovative techniques, materials, procedures and equipment utilized in the host countries relative to pavement preservation and to evaluate these elements for potential application in the United States.

Key Findings

All the countries visited have made a commitment to design and build long lasting structural pavement sections on their national roadway networks. This decision has caused all of these nations to focus maintenance activities on surface courses in order to preserve the large investment in the underlying layers. This, in turn, promotes the use of relatively low cost seals and thin overlays as the primary maintenance techniques, instead of more costly types of rehabilitation.
By providing initial high structural capacity, emphasis is placed on the structure using relatively low cost seals and thin overlays on set, repeatable cycles. For the most part, rehabilitation is a minor portion of the agencies maintenance program. Consequently, pavement preservation techniques are emphasized.
All three countries use only quality materials for both bitumen and aggregate. Generally, crushed aggregate and proven polymer-modified asphalt binders are used. This is ensured through the use of very rigorous specifications. Materials sources are specified and there is no inhibition to using sources a great distance away from the project site.
Warranties, usually four years in duration, are used in contracts when applying preventive maintenance techniques. The functional properties warranted are friction, rutting, and smoothness. The responsibility of the contractor for the repair of non-compliant sections reduces with time and traffic. A secondary effect of the application of warranties has been the innovation of materials and mixtures by contractors and material suppliers.
A system exists in France named the "Charter of Innovation," by which the government and industry share in the risk of experiments to develop new and innovative products. Requests for Proposals (RFPs) are issued annually for new products and test sections are constructed. Surveys are conducted and the company and the government share in the cost of them. Successful products are then accepted nationally for inclusion in the preventive maintenance program.

Recommendations

After discussing and evaluating what they had seen, heard, and experienced in the three countries, the team got together at the end of the tour to review their findings and developed the following recommendations that may have a potential for implementation in the United States:

Demonstration projects with deep subbase and deep base designs be initiated in different regions of the United States to determine the effectiveness of this design strategy.
Agencies include pre-coating of chips in their chip seal specifications.
Geotextile-reinforced chip seals be tested and evaluated in both freeze and no-freeze environments.
Agencies that do not use modified binders for chip seals should be encouraged to do so.
Encourage agencies to review their specifications and upgrade them where appropriate so that superior aggregates are used and improved service life is accomplished.
Encourage agencies to review their design practices for chip seals and consider placing them on base or subbase courses to prevent moisture infiltration.
Chip seals should be applied earlier in the distress cycle.
The successful practice in New South Wales of placing thin (40-60 mm) asphalt overlays on PCCP should be investigated.
AASHTO and FHWA should develop a mechanism to evaluate and implement new and innovative products and processes.
AASHTO and/or FHWA should conduct a seminar to share best practices and also investigate the possibility of demonstration projects in the United States using long-term maintenance contracts.
An investigation of Road Crack^TM and similar vehicles be conducted to fully evaluate the potential for use by transportation agencies. And, if warranted, a pilot program be developed for a side-by-side field evaluation of these vehicles.

Status

A group of the scanning team members has developed a technology implementation plan that outlines a series of activities to document, showcase, apply and evaluate the innovative pavement preservation techniques, processes, materials and equipment utilized in the tour hosting nations. These activities will be directed to educate and demonstrate to the United States highway community the effectiveness and value of these innovative technologies.

STIP Recommendations

The Scan Team identified five major technologies worthy of further evaluation and subsequent implementation. They include innovative chip seal design and construction procedures, use of preventive maintenance as part of pavement management strategies; high speed road condition survey equipment; deep subbase, base; and contract maintenance. The Team has STIP recommendations on the first four. Contract maintenance is being handled separately.

The Proposal is divided into three major tasks. The first two cover information gathering; the third covers a demonstration project concept to demonstrate the technology evaluated as part of the first two task activities.

Task 1 Scout Team - Information Gathering - Australia

While the host countries provided ample information on many subjects, the STIP Team does not believe it has enough detailed data to warrant the recommendations in Phase II without further investigation. It is proposed that a four person "scout" team be assembled to investigate further details associated with the following topics:

Task 1.1 Investigate Chip Seal Design Procedure Review, Including use on Bases and Subbases

Although chip seals are commonly used in the United States, Australia is one of the countries visited that have developed innovative design procedures and application techniques not commonly used in the United States. Performance lives up to 15 years are being achieved on sections with up to 60,000 vehicles per day. This outstanding performance is due in part to the deep-strength pavement designs employed.

Throughout Australia, treatments called geotextile-reinforced sprayed seals have been very successful. These treatments, which involve tack coating the existing pavement, spreading a geotextile, and capping with a chip seal, are used on roadways with moderate cracking. These treatments have proven to retard reflective cracking in Australia's wet and dry no-freeze climates. In addition to the geotextile, it is believed that modified binders, including crumb rubber, aid in the retardation of reflective cracking. These treatments have also been used directly on subgrade and have proven very successful in retarding damage to this material, provided no traffic is allowed during saturated conditions.

Another unique application used in Australia that deserves evaluation is the use of fibers applied directly on the bitumen before the application of the cover aggregate. The fibers enhance both aggregate retention and treatment performance.

To prevent moisture infiltration and capillary action, the Australians often place a chip seal on the base or subbase prior to placing the asphalt surface. This technique is especially useful on highly moisture susceptible bases and subbases. The Australians also perform designs to optimize application rates for the type and gradation/grade of aggregates and bitumen used. Precoating of chip seal aggregates with polymer-modified binders is an example of this aggregate and bitumen use.

Regarding the first two topics, the scout team would gather detailed information on design procedures, construction specifications, materials selection, material testing concepts, and pre-construction pavement conditions. However, the primary goal is to witness active construction, evaluate constructed sites and review management data.

Task 1.2 Investigate the use of Preventive Maintenance Strategies in Pavement Management Systems

Asset Management programs for pavement maintenance are used by all state road agencies in Australia. These programs are similar to Pavement Management Systems (PMS) in the US and vary from state to state. Australian States have realized the importance of asset management for two reasons. First, asset management provides information and data that enable the state transportation authorities to better manage their systems. Secondly, it provides a means to demonstrate to management the importance of and needs for additional funding for their road assets.

Queensland Main Roads has developed in-house software to serve as a decision support tool for the road asset maintenance policy and strategy at the State and District level. The age of surface seals is modeled in PMS and used as the primary predictive trigger for reseal applications. Modeling is based on empirical as well as mechanistic analysis. Other states such as Western Australia Main Roads use commercially available software for this purpose. Regions submit projects to the state transportation offices where a mix of projects are selected. The project mix is based in part on pavement management data and analysis and in part on local factors.

Deliverable: Create a detailed report with the procedures and factors used to identify and program preventive maintenance strategies in Pavement Management Systems. Document preventive maintenance policies and how agencies gain top management support for preventive maintenance program. The gathered information will be used in the development of the NHI course "Integration of Preventive Maintenance into Pavement Management Systems."

Task 1.3 Investigate Road Crack^TM Equipment

In the State of New South Wales, the team was made aware of a high-speed pavement condition survey vehicle capable of detecting pavement cracks as small as one mm in width. The Road Transportation Authority (RTA) of New South Wales has developed the Road Crack^TM vehicle that meets this need. This vehicle has the potential of saving significant resources in transportation agencies throughout the US and other countries. The Team did not see the equipment while in Australia and would like to gather more information. The team will request additional information about the subject equipment from New South Wales and conduct a survey to determine the status of similar technology in the US and Canada.

Task 1 Deliverable: Detailed reports on each subject with specific and detailed implementation package on all three subjects, including hands-on experience with the specific technologies. A workshop to demonstrate the capabilities of all the vendors of this technology will be conducted as part of Task 3.

Timeline

The scout team has initiated formal communication with Australian Transportation Officials to coordinate a visit to Australia no later than December 2002. Upon the scout team's return, a technical working group will evaluate the information, select the specific climates and sites for demonstrations, and assist the host state in developing design and construction documents. This should be done by January of 2003. The actual demonstrations should be constructed in Summer 2003.

Task 2. FHWA Staff Study - Exam Deep Subbase, Deep Base, and Extended Pavement Design Life

This topic was identified on previous scans. Some work has been done in the US but it is not clear as to what has been learned to date or how the technology might impact US practices. It is proposed that FHWA Staff prepare a status report on work contemplated or completed to date and make a recommendation to the STIP team as to the merits of moving forward with this work.

Deliverable: Complete analysis of the concept, presentation of work done in US, its performance, and a recommendation on how it should be further implemented nationwide. Report shall be detailed enough to allow movement towards actual demonstrations in Task 3.

Task 3. Seminar and Demonstration Project

When the scout team and FHWA staff completes their work, the information gathered will need to be fully comprehended by a broader body of US engineers and managers. The goal is to actually construct a demonstration project that includes all the new techniques that were investigated. A seminar will be included with the open house. A host State will be selected and should come from one of the States on the scan. TX, MI, PA, and GA DOTs have all expressed interest in building the demonstration sites and hosting the seminar and open house. The Foundation for Pavement Preservation has expressed interest in helping coordinate the demonstration projects.

Miscellaneous Products and Activities

The following list identifies recommended products and activities that will compliment the main implementation tasks identified in the first part of the STIP:

Products:

Scanning Tour General Report. (Printing pending)
FOCUS article showcasing the Scan key findings and recommendations. (Done)
Brief Reports highlighting key technical and management concepts features of the innovative pavement preservation techniques and processes identified by the scanning team.
Web site dedicated to disseminate scanning tour findings and implementation activities. The site will include links to other pavement preservation sites such as the Foundation for Pavement Preservation, ISSA, ARRA, plus websites from transportation agencies or industry organizations in the visited countries. This will be coordinated with the FHWA Office of International Programs and the Construction and System Preservation Team in the Office of Asset Management. (Need to coordinate with FHWA-Office of Asset Management and FP²)
Create a compact disc with presentations, technical reports and examples of the innovative pavement preservation techniques and processes from the visited Countries and the United States. (Pending follow-up visit to Australia)
Create technical modules that could be included in present and/or future pavement preservation training courses. (Pending follow-up visit to Australia)
Develop guide specifications or procedures for pavement preventive maintenance that are tailored to conditions in the United States.
Identify and Develop Research Statement(s) to evaluate the use of better aggregates, geotextiles and binder application procedures in preventive maintenance treatments.
Prepare reports documenting the implementation and results of the field demonstrations.

Activities:

Presentations at international, national and local meetings sponsored by FHWA, NACE AASHTO, TRB, Foundation for Pavement Preservation, ACPA, APWA, etc. ( Underway)
National Workshop on Innovative Maintenance Contracting sponsor by AASHTO, APWA and FHWA. This will be coordinated with the AASHTO Contract Maintenance Task Force.
Regional Pavement Preservation Workshops, including international technology-sharing activities.
Showcase innovative pavement preservation techniques in NHI Pavement Preservation Training Courses. (Pending follow-up visit to Australia)
Field demonstration projects in various States using the innovative techniques, processes, materials and equipment identified during the scanning tour such as Chip Seals applications, Deep Subbase, and Deep Base pavement structural design. (Pending follow-up visit to Australia)
Conduct a national workshop that will demonstrate the latest pavement distress survey technology in the world. (Pending follow-up visit to Australia)

Key Contact

Luis M. Rodriguez, P.E.
Pavement Management Engineer
Federal Highway Administration
Southern Resource Center
61 Forsyth Street S.W. Suite 17T26
Atlanta, Georgia 30303
Telephone: 404-562-3681
Fax: 404-562-3700
E-mail: luis.rodriguez@fhwa.dot.gov

Design and Analysis Materials and Construction Technology Management and Preservation Surface Characteristics Construction and Materials Quality Assurance Environmental Stewardship	Pavement Preservation Scanning Tour Status Report (7/2002) Background Traditionally, highway agencies have allowed the ride quality and structural condition of their pavements to deteriorate to fair or poor condition before taking steps to rehabilitate the pavements. The aim of rehabilitation is to repair structural damage and restore measurable pavement conditions such as ride, rutting and cracking. This is a costly and time consuming activity with associated traffic disruptions and inconvenience to adjacent businesses and residences. In recent years, an increasing number of highway agencies have found that applying a series of low-cost pavement preservation treatments can extend the service lives of their pavements. This translates into a better investment and increased customer satisfaction and support. France, South Africa and Australia were identified as nations that have innovative programs as well as new treatments for pavement preservation. Goal The goal of this scanning tour was to review and document innovative techniques, materials, procedures and equipment utilized in the host countries relative to pavement preservation and to evaluate these elements for potential application in the United States. Key Findings All the countries visited have made a commitment to design and build long lasting structural pavement sections on their national roadway networks. This decision has caused all of these nations to focus maintenance activities on surface courses in order to preserve the large investment in the underlying layers. This, in turn, promotes the use of relatively low cost seals and thin overlays as the primary maintenance techniques, instead of more costly types of rehabilitation. By providing initial high structural capacity, emphasis is placed on the structure using relatively low cost seals and thin overlays on set, repeatable cycles. For the most part, rehabilitation is a minor portion of the agencies maintenance program. Consequently, pavement preservation techniques are emphasized. All three countries use only quality materials for both bitumen and aggregate. Generally, crushed aggregate and proven polymer-modified asphalt binders are used. This is ensured through the use of very rigorous specifications. Materials sources are specified and there is no inhibition to using sources a great distance away from the project site. Warranties, usually four years in duration, are used in contracts when applying preventive maintenance techniques. The functional properties warranted are friction, rutting, and smoothness. The responsibility of the contractor for the repair of non-compliant sections reduces with time and traffic. A secondary effect of the application of warranties has been the innovation of materials and mixtures by contractors and material suppliers. A system exists in France named the "Charter of Innovation," by which the government and industry share in the risk of experiments to develop new and innovative products. Requests for Proposals (RFPs) are issued annually for new products and test sections are constructed. Surveys are conducted and the company and the government share in the cost of them. Successful products are then accepted nationally for inclusion in the preventive maintenance program. Recommendations After discussing and evaluating what they had seen, heard, and experienced in the three countries, the team got together at the end of the tour to review their findings and developed the following recommendations that may have a potential for implementation in the United States: Demonstration projects with deep subbase and deep base designs be initiated in different regions of the United States to determine the effectiveness of this design strategy. Agencies include pre-coating of chips in their chip seal specifications. Geotextile-reinforced chip seals be tested and evaluated in both freeze and no-freeze environments. Agencies that do not use modified binders for chip seals should be encouraged to do so. Encourage agencies to review their specifications and upgrade them where appropriate so that superior aggregates are used and improved service life is accomplished. Encourage agencies to review their design practices for chip seals and consider placing them on base or subbase courses to prevent moisture infiltration. Chip seals should be applied earlier in the distress cycle. The successful practice in New South Wales of placing thin (40-60 mm) asphalt overlays on PCCP should be investigated. AASHTO and FHWA should develop a mechanism to evaluate and implement new and innovative products and processes. AASHTO and/or FHWA should conduct a seminar to share best practices and also investigate the possibility of demonstration projects in the United States using long-term maintenance contracts. An investigation of Road Crack^TM and similar vehicles be conducted to fully evaluate the potential for use by transportation agencies. And, if warranted, a pilot program be developed for a side-by-side field evaluation of these vehicles. Status A group of the scanning team members has developed a technology implementation plan that outlines a series of activities to document, showcase, apply and evaluate the innovative pavement preservation techniques, processes, materials and equipment utilized in the tour hosting nations. These activities will be directed to educate and demonstrate to the United States highway community the effectiveness and value of these innovative technologies. STIP Recommendations The Scan Team identified five major technologies worthy of further evaluation and subsequent implementation. They include innovative chip seal design and construction procedures, use of preventive maintenance as part of pavement management strategies; high speed road condition survey equipment; deep subbase, base; and contract maintenance. The Team has STIP recommendations on the first four. Contract maintenance is being handled separately. The Proposal is divided into three major tasks. The first two cover information gathering; the third covers a demonstration project concept to demonstrate the technology evaluated as part of the first two task activities. Task 1 Scout Team - Information Gathering - Australia While the host countries provided ample information on many subjects, the STIP Team does not believe it has enough detailed data to warrant the recommendations in Phase II without further investigation. It is proposed that a four person "scout" team be assembled to investigate further details associated with the following topics: Task 1.1 Investigate Chip Seal Design Procedure Review, Including use on Bases and Subbases Although chip seals are commonly used in the United States, Australia is one of the countries visited that have developed innovative design procedures and application techniques not commonly used in the United States. Performance lives up to 15 years are being achieved on sections with up to 60,000 vehicles per day. This outstanding performance is due in part to the deep-strength pavement designs employed. Throughout Australia, treatments called geotextile-reinforced sprayed seals have been very successful. These treatments, which involve tack coating the existing pavement, spreading a geotextile, and capping with a chip seal, are used on roadways with moderate cracking. These treatments have proven to retard reflective cracking in Australia's wet and dry no-freeze climates. In addition to the geotextile, it is believed that modified binders, including crumb rubber, aid in the retardation of reflective cracking. These treatments have also been used directly on subgrade and have proven very successful in retarding damage to this material, provided no traffic is allowed during saturated conditions. Another unique application used in Australia that deserves evaluation is the use of fibers applied directly on the bitumen before the application of the cover aggregate. The fibers enhance both aggregate retention and treatment performance. To prevent moisture infiltration and capillary action, the Australians often place a chip seal on the base or subbase prior to placing the asphalt surface. This technique is especially useful on highly moisture susceptible bases and subbases. The Australians also perform designs to optimize application rates for the type and gradation/grade of aggregates and bitumen used. Precoating of chip seal aggregates with polymer-modified binders is an example of this aggregate and bitumen use. Regarding the first two topics, the scout team would gather detailed information on design procedures, construction specifications, materials selection, material testing concepts, and pre-construction pavement conditions. However, the primary goal is to witness active construction, evaluate constructed sites and review management data. Task 1.2 Investigate the use of Preventive Maintenance Strategies in Pavement Management Systems Asset Management programs for pavement maintenance are used by all state road agencies in Australia. These programs are similar to Pavement Management Systems (PMS) in the US and vary from state to state. Australian States have realized the importance of asset management for two reasons. First, asset management provides information and data that enable the state transportation authorities to better manage their systems. Secondly, it provides a means to demonstrate to management the importance of and needs for additional funding for their road assets. Queensland Main Roads has developed in-house software to serve as a decision support tool for the road asset maintenance policy and strategy at the State and District level. The age of surface seals is modeled in PMS and used as the primary predictive trigger for reseal applications. Modeling is based on empirical as well as mechanistic analysis. Other states such as Western Australia Main Roads use commercially available software for this purpose. Regions submit projects to the state transportation offices where a mix of projects are selected. The project mix is based in part on pavement management data and analysis and in part on local factors. Deliverable: Create a detailed report with the procedures and factors used to identify and program preventive maintenance strategies in Pavement Management Systems. Document preventive maintenance policies and how agencies gain top management support for preventive maintenance program. The gathered information will be used in the development of the NHI course "Integration of Preventive Maintenance into Pavement Management Systems." Task 1.3 Investigate Road Crack^TM Equipment In the State of New South Wales, the team was made aware of a high-speed pavement condition survey vehicle capable of detecting pavement cracks as small as one mm in width. The Road Transportation Authority (RTA) of New South Wales has developed the Road Crack^TM vehicle that meets this need. This vehicle has the potential of saving significant resources in transportation agencies throughout the US and other countries. The Team did not see the equipment while in Australia and would like to gather more information. The team will request additional information about the subject equipment from New South Wales and conduct a survey to determine the status of similar technology in the US and Canada. Task 1 Deliverable: Detailed reports on each subject with specific and detailed implementation package on all three subjects, including hands-on experience with the specific technologies. A workshop to demonstrate the capabilities of all the vendors of this technology will be conducted as part of Task 3. Timeline The scout team has initiated formal communication with Australian Transportation Officials to coordinate a visit to Australia no later than December 2002. Upon the scout team's return, a technical working group will evaluate the information, select the specific climates and sites for demonstrations, and assist the host state in developing design and construction documents. This should be done by January of 2003. The actual demonstrations should be constructed in Summer 2003. Task 2. FHWA Staff Study - Exam Deep Subbase, Deep Base, and Extended Pavement Design Life This topic was identified on previous scans. Some work has been done in the US but it is not clear as to what has been learned to date or how the technology might impact US practices. It is proposed that FHWA Staff prepare a status report on work contemplated or completed to date and make a recommendation to the STIP team as to the merits of moving forward with this work. Deliverable: Complete analysis of the concept, presentation of work done in US, its performance, and a recommendation on how it should be further implemented nationwide. Report shall be detailed enough to allow movement towards actual demonstrations in Task 3. Task 3. Seminar and Demonstration Project When the scout team and FHWA staff completes their work, the information gathered will need to be fully comprehended by a broader body of US engineers and managers. The goal is to actually construct a demonstration project that includes all the new techniques that were investigated. A seminar will be included with the open house. A host State will be selected and should come from one of the States on the scan. TX, MI, PA, and GA DOTs have all expressed interest in building the demonstration sites and hosting the seminar and open house. The Foundation for Pavement Preservation has expressed interest in helping coordinate the demonstration projects. Miscellaneous Products and Activities The following list identifies recommended products and activities that will compliment the main implementation tasks identified in the first part of the STIP: Products: Scanning Tour General Report. (Printing pending) FOCUS article showcasing the Scan key findings and recommendations. (Done) Brief Reports highlighting key technical and management concepts features of the innovative pavement preservation techniques and processes identified by the scanning team. Web site dedicated to disseminate scanning tour findings and implementation activities. The site will include links to other pavement preservation sites such as the Foundation for Pavement Preservation, ISSA, ARRA, plus websites from transportation agencies or industry organizations in the visited countries. This will be coordinated with the FHWA Office of International Programs and the Construction and System Preservation Team in the Office of Asset Management. (Need to coordinate with FHWA-Office of Asset Management and FP²) Create a compact disc with presentations, technical reports and examples of the innovative pavement preservation techniques and processes from the visited Countries and the United States. (Pending follow-up visit to Australia) Create technical modules that could be included in present and/or future pavement preservation training courses. (Pending follow-up visit to Australia) Develop guide specifications or procedures for pavement preventive maintenance that are tailored to conditions in the United States. Identify and Develop Research Statement(s) to evaluate the use of better aggregates, geotextiles and binder application procedures in preventive maintenance treatments. Prepare reports documenting the implementation and results of the field demonstrations. Activities: Presentations at international, national and local meetings sponsored by FHWA, NACE AASHTO, TRB, Foundation for Pavement Preservation, ACPA, APWA, etc. ( Underway) National Workshop on Innovative Maintenance Contracting sponsor by AASHTO, APWA and FHWA. This will be coordinated with the AASHTO Contract Maintenance Task Force. Regional Pavement Preservation Workshops, including international technology-sharing activities. Showcase innovative pavement preservation techniques in NHI Pavement Preservation Training Courses. (Pending follow-up visit to Australia) Field demonstration projects in various States using the innovative techniques, processes, materials and equipment identified during the scanning tour such as Chip Seals applications, Deep Subbase, and Deep Base pavement structural design. (Pending follow-up visit to Australia) Conduct a national workshop that will demonstrate the latest pavement distress survey technology in the world. (Pending follow-up visit to Australia) Key Contact Luis M. Rodriguez, P.E. Pavement Management Engineer Federal Highway Administration Southern Resource Center 61 Forsyth Street S.W. Suite 17T26 Atlanta, Georgia 30303 Telephone: 404-562-3681 Fax: 404-562-3700 E-mail: luis.rodriguez@fhwa.dot.gov	Events NCPP Calendar of Events View all Upcoming Pavements Events More Information Office of Asset Management's Pavement Management Group Pavement Publications System Preservation Contacts Luis Rodriguez Resource Center (Atlanta) 404-562-3681 E-mail Luis Celso Gatchalian Office of Asset Management 202-366-1342 E-mail Celso
	This page last modified on 06/29/06