Sustainable Pavement Maintenance Practices (2011)

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Research Results Digest 365 NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM December 2011 C O N T E N T S Summary, 1 Introduction, 3 Synthesis Objective, 3 Background, 3 Key Definitions, 4 Sustainability Impact Factor Areas, 5 Study Approach, 6 Summary of Literature Review and Survey and Results, 6 Introduction, 6 Opportunities to Implement Sustainability in Maintenance, 7 Sustainability Within Agency Maintenance Programs, 9 Summary, 10 Quantifying Environmental Sustainability in Pavement Preservation and Maintenance, 10 Introduction, 10 Summary, 13 Case Studies, 13 Case Study Descriptions, 13 Results from Case Studies, 20 Summary, 22 Conclusions and Future Research Needs, 22 Conclusions, 22 Future Research Needs, 22 References, 23 Glossary of Acronyms and Terms, 25 Appendices A and B, 26 SUMMARY Today’s transportation agencies, faced with the difficulty of meeting pavement maintenance and performance goals with limited budgets, are further challenged to ensure that their efforts contribute to their organizations’ desire for environmental sustainability. In 1987, the Bruntdland Commission provided the following global definition for sustainability: “Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs.” Sustainable transporta- tion according to the FHWA is defined as “. . . providing exceptional mobility and access in a manner that meets development needs without compromising the quality of life of future generations. A sustainable transportation system is safe, healthy, affordable, renewable, operates fairly, and limits emissions and the use of new and nonrenewable resources.” This synthesis reports on the state of the practice in sustainable pavement main- tenance and preservation. It is concerned and directed at quantifying and understand- ing how pavement maintenance and preser- vation practices minimize environmental impacts. The FHWA differentiates between pavement preservation and pavement main- tenance and uses this to allocate federal funds accordingly. Although Canadian agencies recognize and practice the con- cepts of pavement preservation, there is no regulatory differentiation between it and maintenance as compared with the United States. Pavement preservation promotes environmental sustainability by conserv- ing energy, virgin materials, and reducing greenhouse gases by keeping good roads good. Therefore, the foundation of a sus- tainable pavement maintenance program is to commit personnel and resources to pave- ment preservation. Currently, public agencies in the United States and Canada have done little to extend the knowledge gained from research and practice in sustainable highway project delivery beyond construction completion and into the pavement preservation and maintenance phase of a road’s life cycle. Therefore, there are many opportunities for future research and enormous potential for agencies to accrue benefits in this area of practice. These potential benefits are diverse and of strategic importance as they encom- pass improvements to virgin material usage, alternative material usage, pavement in- service monitoring and management, noise, air quality, water quality, and energy usage. Treatments identified in this report are pri- marily related to preservation and mainte- nance. However, these are not exclusive to preservation and maintenance and can be used in pavement rehabilitation. SUSTAINABLE PAVEMENT MAINTENANCE PRACTICES This digest contains excerpts from a study conducted for NCHRP Project 20-05, “Synthesis of Information Related to Highway Problems.” The study was conducted by Susan L. Tighe, University of Waterloo, Waterloo, Ontario, Canada, and Douglas D. Gransberg, Iowa State University, Ames, Iowa. Jo Allen Gause is the Senior Program Officer for this study. Senior Program Officer: Nanda Srinivasan

The synthesis provides the summary results of a comprehensive literature review, a survey of U.S. state and Canadian provincial highway agencies, and presentation of eight case studies of agencies that are implementing environmental sustainability programs that involve pavement preservation and maintenance practices. Although the highlighted case studies primarily focus on environmental sus- tainability and how it relates to pavement design and pavement construction, they provide an excellent basis for future application to pavement preservation and maintenance treatment. The survey was issued to state and provincial maintenance engineers in the United States and Canada. A total of 49 responses were received, 42 from U.S. state departments of transportation (DOTs) and 7 from Canadian provin- cial ministries of transportation, yielding response rates of 84% and 70%, respectively. The eight case studies of sustainable pavement programs included four U.S. DOTs (Arizona, New York, Oregon, and Washington State), the Ministry of Transportation in Ontario (MTO), the city of Philadelphia, a Penn- sylvania state-level program for sustainable dirt and gravel road maintenance, and the New Zealand Transport Agency. Each case study demonstrates promotion of environmental performance utilized by the agency that also provides technical and eco- nomic benefits. The major conclusions identified in this report are summarized as follows: • Environmental sustainability research that is related specifically to post-construction oper- ations is an emerging field. • Thin asphalt overlays are the most prevalent preventive maintenance treatment for asphalt and composite pavements. • Diamond grinding and joint sealing are the most commonly used treatments for concrete pavements. • Regrading and regraveling are the most preva- lent treatments for graveled roads, whereas chip seals are the preferred treatment for surface- treated roads. • Quantification of sustainability with pavement preservation and maintenance programs is not commonly practiced in the United States and Canada. • Various construction and design sustainability initiatives are available in the literature; how- ever, an assessment tool to properly quantify environmental sustainability in the pavement preservation and maintenance context is both missing and required. • The case studies demonstrate that environmen- tal sustainability can be incorporated into pave- ment preservation and maintenance practices. One purpose of this synthesis study was to iden- tify gaps in the knowledge of sustainable pavement preservation and maintenance treatments and suggest possible research to address these gaps. Following is a summary of the seven major research needs pre- sented in the report: • There is a need for pavement preservation and maintenance-specific research to furnish agency pavement maintenance engineers with the fundamental data on the relative environ- mental sustainability of common treatments. • There is a need to develop pavement preserva- tion and maintenance-specific life-cycle assess- ment and cost analysis methods that include values for factors such as carbon sequestration, resource renewability, and other salient ele- ments of environmental sustainability to furnish a rational approach to treatment selection. • Research is needed to develop training and information to be disseminated throughout the United States and Canada that quantifies the importance of preservation and maintenance treatments in the environmental sustainability impact factor areas discussed in this report. • There is a need to complete research in adapt- ing recycled and alternate materials for use in pavement preservation and maintenance treatments. • There is a need for research to identify and develop appropriate noise standards for pave- ment preservation and maintenance operations and life-cycle assessment. • There is a specific need for research to quantify the contribution that crack sealing makes to the environmental sustainability of all types of pavement surfaces to demonstrate its impor- tance in sustainable pavement preservation and maintenance. • There is a need to research policies, technology, materials, specifications, standards, equipment, capacity-building, recycling/waste reduction, emissions reduction (air pollution), and life- cycle cost analysis. In this regard, it is necessary to incorporate sustainable pavement mainte- nance elements into on-going and future pave- ment maintenance research. 2