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December 2011 NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM Senior Program Officer: Nanda Srinivasan Research Results Digest 365 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. SUMMARY agencies recognize and practice the con- cepts of pavement preservation, there is no Today's transportation agencies, faced regulatory differentiation between it and with the difficulty of meeting pavement maintenance as compared with the United maintenance and performance goals with States. Pavement preservation promotes limited budgets, are further challenged to ensure that their efforts contribute to their environmental sustainability by conserv- organizations' desire for environmental ing energy, virgin materials, and reducing C O N T E N T S sustainability. In 1987, the Bruntdland greenhouse gases by keeping good roads Summary, 1 Commission provided the following global good. Therefore, the foundation of a sus- Introduction, 3 definition for sustainability: "Sustainable tainable pavement maintenance program is Synthesis Objective, 3 Background, 3 development is development that meets the to commit personnel and resources to pave- Key Definitions, 4 needs of the present without compromising ment preservation. Sustainability Impact Factor Areas, 5 the ability of future generations to meet Currently, public agencies in the United Study Approach, 6 their own needs." Sustainable transporta- States and Canada have done little to extend Summary of Literature Review tion according to the FHWA is defined as the knowledge gained from research and and Survey and Results, 6 Introduction, 6 ". . . providing exceptional mobility and practice in sustainable highway project Opportunities to Implement access in a manner that meets development delivery beyond construction completion Sustainability in Maintenance, 7 Sustainability Within Agency needs without compromising the quality of and into the pavement preservation and Maintenance Programs, 9 Summary, 10 life of future generations. A sustainable maintenance phase of a road's life cycle. transportation system is safe, healthy, Therefore, there are many opportunities for Quantifying Environmental Sustainability in Pavement affordable, renewable, operates fairly, and future research and enormous potential for Preservation and Maintenance, 10 Introduction, 10 limits emissions and the use of new and agencies to accrue benefits in this area of Summary, 13 nonrenewable resources." practice. These potential benefits are diverse Case Studies, 13 This synthesis reports on the state of and of strategic importance as they encom- Case Study Descriptions, 13 Results from Case Studies, 20 the practice in sustainable pavement main- pass improvements to virgin material usage, Summary, 22 tenance and preservation. It is concerned alternative material usage, pavement in- Conclusions and Future and directed at quantifying and understand- service monitoring and management, noise, Research Needs, 22 Conclusions, 22 ing how pavement maintenance and preser- air quality, water quality, and energy usage. Future Research Needs, 22 vation practices minimize environmental Treatments identified in this report are pri- References, 23 impacts. The FHWA differentiates between marily related to preservation and mainte- Glossary of Acronyms pavement preservation and pavement main- nance. However, these are not exclusive to and Terms, 25 tenance and uses this to allocate federal preservation and maintenance and can be Appendices A and B, 26 funds accordingly. Although Canadian used in pavement rehabilitation.
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The synthesis provides the summary results of preservation and maintenance context is both a comprehensive literature review, a survey of U.S. missing and required. state and Canadian provincial highway agencies, · The case studies demonstrate that environmen- and presentation of eight case studies of agencies tal sustainability can be incorporated into pave- that are implementing environmental sustainability ment preservation and maintenance practices. programs that involve pavement preservation and One purpose of this synthesis study was to iden- maintenance practices. Although the highlighted tify gaps in the knowledge of sustainable pavement case studies primarily focus on environmental sus- preservation and maintenance treatments and suggest tainability and how it relates to pavement design and possible research to address these gaps. Following is pavement construction, they provide an excellent a summary of the seven major research needs pre- basis for future application to pavement preservation sented in the report: and maintenance treatment. The survey was issued to state and provincial maintenance engineers in the · There is a need for pavement preservation United States and Canada. A total of 49 responses and maintenance-specific research to furnish were received, 42 from U.S. state departments of agency pavement maintenance engineers with transportation (DOTs) and 7 from Canadian provin- the fundamental data on the relative environ- cial ministries of transportation, yielding response mental sustainability of common treatments. rates of 84% and 70%, respectively. The eight case · There is a need to develop pavement preserva- studies of sustainable pavement programs included tion and maintenance-specific life-cycle assess- four U.S. DOTs (Arizona, New York, Oregon, and ment and cost analysis methods that include Washington State), the Ministry of Transportation values for factors such as carbon sequestration, in Ontario (MTO), the city of Philadelphia, a Penn- resource renewability, and other salient ele- sylvania state-level program for sustainable dirt ments of environmental sustainability to furnish and gravel road maintenance, and the New Zealand a rational approach to treatment selection. Transport Agency. Each case study demonstrates · Research is needed to develop training and promotion of environmental performance utilized information to be disseminated throughout the by the agency that also provides technical and eco- United States and Canada that quantifies the nomic benefits. importance of preservation and maintenance The major conclusions identified in this report treatments in the environmental sustainability are summarized as follows: impact factor areas discussed in this report. · There is a need to complete research in adapt- · Environmental sustainability research that is ing recycled and alternate materials for use related specifically to post-construction oper- in pavement preservation and maintenance ations is an emerging field. treatments. · Thin asphalt overlays are the most prevalent · There is a need for research to identify and preventive maintenance treatment for asphalt develop appropriate noise standards for pave- and composite pavements. ment preservation and maintenance operations · Diamond grinding and joint sealing are the and life-cycle assessment. most commonly used treatments for concrete · There is a specific need for research to quantify pavements. the contribution that crack sealing makes to · Regrading and regraveling are the most preva- the environmental sustainability of all types of lent treatments for graveled roads, whereas chip pavement surfaces to demonstrate its impor- seals are the preferred treatment for surface- tance in sustainable pavement preservation and treated roads. maintenance. · Quantification of sustainability with pavement · There is a need to research policies, technology, preservation and maintenance programs is not materials, specifications, standards, equipment, commonly practiced in the United States and capacity-building, recycling/waste reduction, Canada. emissions reduction (air pollution), and life- · Various construction and design sustainability cycle cost analysis. In this regard, it is necessary initiatives are available in the literature; how- to incorporate sustainable pavement mainte- ever, an assessment tool to properly quantify nance elements into on-going and future pave- environmental sustainability in the pavement ment maintenance research. 2