U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
202-366-4000
Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations
| Project Information | ||
| Project ID: | FHWA-PROJ-14-0127 | |
| Project Name: | Porous-Graded Asphalt | |
| Project Status: | Active | |
| Start Date: | September 1, 2014 | |
| End Date: | August 31, 2017 | |
| Contact Information | ||
| Last Name: | Weaver | |
| First Name: | Eric J | |
| Telephone: | 202-493-3153 | |
| E-mail: | eric.weaver@dot.gov | |
| Office: | Office of Infrastructure Research and Development | |
| Team: | Infrastructure Analysis and Construction Team [HRDI-20] | |
| Program: | Innovative Pavement Research and Deployment | |
| Project detail | ||
| Roadmap/Focus area(s): | Infrastructure Research and Technology Strategic Plan and Roadmap | |
| Project Description: | The objective of this research is to support Federal Highway Administration (FHWA) by advancing the current knowledge and state-of-the-practice in the sciences and technologies utilized in the planning, design, construction, operation, maintenance and management of the porous-graded asphalt (PGA) used in the Nations highways. This will require synthesizing relevant information available and building upon that information to develop and carry out a research and implementation plan. Strategically, this research will enable and expedite the development and deployment of PGA, which will greatly improve the safety and efficiency of highway transportation. | |
| Goals: | Develop and deliver a porous-graded asphalt design system that includes site selection, materials selection, mix design, structural design, and construction and maintenance guidance. | |
| Background Information: | Safety is a primary concern of the United States of America (USA) Department of Transportation (DOT) Federal Highway Administration (FHWA). For roadway vehicular traffic, the factors having primary influence on safety, aside from the vehicles and motorists, are geometric design, traffic control devices and pavement surface characteristics. For pavements, the surface characteristics are controllable, primarily in terms of pavement mix design and construction quality. Two of the main aspects of pavement surfaces that affect safety are skid resistance and splash and spray during inclement weather. Pavement surface types that have an open aggregate gradation prevent surface water collecting in travelling lanes that provides an obvious safety benefit in terms of reduced hydroplane potential as well as improved driver visibility through reduction in splash and spray. At the same time, these open or porous pavement surfaces tend to improve frictional aspects that reduce vehicle-to-vehicle collisions and roadway departures, especially in wet surface conditions. These characteristics of surface mixes are often associated with a reduction in tire noise, which may reduce noise control mitigation requirements. Another factor where PGAs may play a positive role is through the retention of surface water runoff contaminants to prevent immediate discharge into the watershed. Pavement surfaces that meet this description are Open Graded Friction Courses (OGFS) and Permeable Friction Courses (PFC). Differences between these include the thickness of the surface course, gradation of the mix, and the resulting air voids in the asphalt-aggregate matrix. These are also surface mixes, meaning that they overlay nonpermeable layers, whereas full depth permeable pavements allow water to penetrate through the entire structure. For the purpose of this Statement of Work, the term Porous-Graded Asphalt (PGA) pavements refers to all of these types. In some cases, State highway agency (SHA) experience has been quite positive with these mixes, and as a result they were implemented for the benefits mentioned above. In addition, some of these mixes are being successfully used in other countries. However, some SHAs have had negative experiences in the past, mostly because of reduced service life associated with excessive raveling following numerous freeze and thaw events. Another concern that agencies raise with these mixes is their impact on snow and ice control maintenance operations. Because of their porosity, standard snow and ice control treatments may require higher application rates and other operational changes from conventional surface mixes. In addition, over time, the pores in these mixes have filled with debris. It is possible that poor PGA performance was related to a lack of understanding of materials selection and application of proper construction practices that are critical to PGA performance. Considerable advancements in the understanding of these factors are believed to contribute to PGA designs with enhanced performance. In recent years, significant research investments have been made to improve asphalt binders with various additives, and the time is right to examine how these and other advances can be applied to increasing the durability of PGA mixes. Doing so will increase the appeal of these mixes so that their safety and environmental benefits can be realized by a greater percentage of the driving public. Guidelines are also needed to convey the construction and maintenance practices that are required for increased durability. The National Cooperative Highway Research Program (NCHRP) published the Synthesis of Highway Practice 284: Performance Survey on Open-Graded Friction Course Mixes in 2000." Recommended future research areas included mix design, cleaning pores, modified asphalt binders, and maintenance strategies. These topics have been explored to a large extent by NCHRP Report 640 Construction and Maintenance Practices for Permeable Friction Courses (2009), Evaluation and Recommended Improvements for Mix Design of Permeable Friction Courses," (Alvarez et al 2008) and Performance and Cost Effectiveness of Permeable Friction Course (PFC) Pavements (Arámbula et al 2013). Despite these efforts, however, the implementation of PGA surface course on the USA National Highway System is not widespread, and therefore the benefits of using PGA surface course are not fully realized. A concerted effort is needed to develop a comprehensive system to design and maintain PGA and develop guidance that can be optimized for requirements that vary by SHA and region on a national basis. Note: The agency selected to conduct this research shall coordinate with those conducting the anticipated NCHRP Project 1-55 Performance-Based Mix Design of Porous Friction Courses. Coordination will be facilitated through the COR and NCHRP staff member. | |
| Field Test: | Yes | |
| Product Type: | Article Data Draft standard, specifications, or guidelines Promotional materials Research report Techbrief Technical report Training materials | |
| Test Methodology: | Literature and industry review, laboratory material preparation, testing and characterization, analytical modeling and field verification. | |
| Partners: | TRB-NCHRP | |
| Expected Benefits: | Expanded market penetration and beneficial aspects of porous- graded asphalt mixtures for pavements, including reduced noise, reduced splash and spray, and improved friction. | |
| Deliverables: | 1. Name: Porous-Graded Asphalt Design System Product Type(s): Research report, Training materials, Promotional materials, Draft standard, specifications, or guidelines, Techbrief, Technical report, Article Description: A Porous-Graded Asphalt Design System that includes site selection, materials selection, mix design, structural design, and construction and maintenance guidance. 2. Name: Supporting dataset Product Type(s): Data Description: All data generated in support of the final product and deliverable. | |
| FHWA Topics: | Research/Technologies--FHWA Research and Technology | |
| TRT Terms: | Pavements Infrastructure Research Porous Pavements Asphalt Mixtures Design Construction Highways |
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| FHWA Disciplines: | Construction and Project Management Pavement and Materials Safety |
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| Subject Areas: | Construction Design Highways Maintenance and Preservation Materials Pavements Research |
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