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The scanning team formed a small group to develop a scan technology implementation plan. The plan outlines a series of activities to document, showcase, apply, and evaluate the innovative pavement preservation techniques, processes, materials, and equipment observed in the host nations. These activities focus on educating and demonstrating to the U.S. highway community the effectiveness and value of these innovative technologies. The implementation plan team includes James Moulthrop of the Foundation for Pavement Preservation, Luis Rodriguez and Michael Voth of FHWA, and Zane Webb of Texas DOT.
The scanning team identified five major technologies worthy of further evaluation and subsequent implementation. They include innovative chip seal design and construction procedures, preventive maintenance as part of pavement management strategies, high-speed road condition survey equipment, deep subbase and deep base design, and contract maintenance. The team has developed implementation recommendations on the first four technologies. Contract maintenance will be handled separately.
The implementation proposal is divided into three major tasks. The first two tasks involve information gathering, while the third calls for a project to demonstrate the technology evaluated as part of the first two tasks.
While the host countries provided ample information on many subjects, the implementation plan team does not believe it has enough detailed data to warrant proceeding with its recommendations without further investigation. The team proposes that a four-person scout team be assembled to investigate further the following topics:
Investigate chip seal design procedure, including use on bases and subbases -Although chip seals are commonly used in the United States, Australia is one of the countries visited that has developed innovative design procedures and application techniques not normally used in the United States. Performance lives of 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 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 retard reflective cracking in Australia's wet and dry no-freeze climates. In addition to 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 successful in slowing 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 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 before placing the asphalt surface. This technique is especially useful on bases and subbases highly susceptible to moisture. The Australians also perform designs to optimize application rates for the type and grade of aggregates and bitumen used. Pre-coating of chip seal aggregates with polymer-modified binders is an example of this aggregate and bitumen use.
The scout team plans to gather detailed information on design procedures, construction specifications, materials selection, material-testing concepts, and pre-construction pavement conditions. The primary goal of the chip seal study, however, is to witness active construction, evaluate constructed sites, and review management data.
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, similar to pavement management systems in the United States, 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. Second, it provides a way to demonstrate to management the importance of and need 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 levels. The age of surface seals is modeled in pavement management systems 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, use commercially available software for this purpose. Regions submit projects to the state transportation offices, where a mix of projects is selected. The project mix is based in part on pavement management data and analysis and in part on local factors.
Deliverable: The team would create a detailed report on the procedures and factors used to identify and program preventive maintenance strategies in pavement management systems. The report would document preventive maintenance policies and how agencies gain top management support for preventive maintenance programs. The gathered information would be used in the development of the National Highway Institute course "Integration of Preventive Maintenance into Pavement Management Systems."
Investigate Road Crackä equipment - In New South Wales, the team learned about a high-speed pavement condition survey vehicle capable of detecting pavement cracks as small as a millimeter wide. The Road Transportation Authority of New South Wales developed the Road Crackä vehicle. The vehicle has the potential of saving significant resources in transportation agencies throughout the United States and other countries. The team did not see the equipment while in Australia and would like to learn more about it. The team will ask New South Wales officials for more information and conduct a survey to determine the availability of similar technology in the United States and Canada.
Deliverable: The team would prepare detailed reports with specific implementation recommendations on all three subjects, including hands-on experience with the specific technologies. A workshop to demonstrate the capabilities of vendors of this technology would be conducted as part of Task 3.
This topic was identified on previous scans. Some work has been done in the United States, but it is not clear what impact the technology might have on U.S. practices. The team recommends that FHWA staff prepare a status report on work contemplated or completed and make a recommendation to the implementation plan team on the merits of moving forward with this work.
Deliverable: FHWA staff would prepare a complete analysis of the concept, presentation of work done in the United States and its performance, and a recommendation on how it should be further implemented nationwide. The report would be detailed enough to allow movement towards actual demonstrations in Task 3.
Once the scout team and FHWA staff complete their work, the information gathered needs to be disseminated broadly to transportation engineers and managers throughout the United States. The goal is to construct a demonstration project that includes the new techniques investigated. A seminar would be included with the open house for the project. A host State would be chosen from those represented on the scanning team. Texas, Michigan, Pennsylvania, and Georgia DOTs all have expressed interest in building demonstration projects and hosting a seminar and open house. The Foundation for Pavement Preservation has expressed interest in helping coordinate the demonstration projects.
The scout team hopes to visit Australia in 2002. When it returns, a technical working group plans to evaluate the information, select the specific climates and sites for demonstration projects, and help the host State develop design and construction documents by the end of 2002. The actual demonstration projects would be constructed in 2003.
The following list identifies recommended products and activities that would complement the main implementation tasks identified in the first part of the scan technology implementation plan. Sponsoring agencies and organizations have not yet been determined for each.
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