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Table 3 Summary responses to environmental and sustainability programmatic questions Do you have an Does your agency agency-wide use environmental "sustainability" Does your agency performance to select program that Does your agency use PMS software maintenance and/or includes pavement have sustainable to monitor preservation maintenance maintenance environmental program practices? activities? specifications? performance No Yes No Yes No Yes No Yes Canada 7 0 5 2 7 0 7 0 U.S. 40 2 38 4 41 1 36 6 Total 47 2 43 6 48 1 43 6 Percentage 96% 4% 88% 12% 98% 2% 88% 12% PMS = Pavement Management System. to maintenance but rather to construction or planning There is a need for pavement preservation and of pavements. A closer look at some of those programs maintenance-specific research to furnish shows that the agency-wide program is focused on agency pavement maintenance engineers with sustainable design and construction with little specific the fundamental data on the relative environ- guidance being given to environmental sustainability mental sustainability of common treatments. within pavement preservation and maintenance. This There is a need to develop a pavement preser- leads to the identification of a need for future efforts to vation and maintenance-specific life-cycle develop the programmatic guidelines and specifica- assessment and cost analysis method that tions needed to implement sustainable pavement includes values for factors such as carbon preservation and maintenance programs. sequestration, resource renewability, and other salient elements of environmental sustainabil- ity to furnish a rational approach to treatment Summary selection. Although agencies are becoming more aware of the significance of the concept of environmental sus- QUANTIFYING ENVIRONMENTAL tainability, this does not translate to direct measures SUSTAINABILITY IN PAVEMENT for use within their maintenance programs. More PRESERVATION AND MAINTENANCE than 80% of responding agencies indicated that their agency did not use environmental performance, nor Introduction did they have agency-wide environmental sustain- This chapter presents the seven environmental ability or sustainable maintenance specifications. sustainability impact factor areas and the extent to which the survey responses used them in their con- Conclusions struction and maintenance decisions. Environmental The following conclusion was reached in this stewardship considers the use of renewable resources chapter: at below their rates of regeneration and nonrenewable resources below rates of development of substitutes Environmental sustainability research that is as noted by the first two environmental sustainability related specifically to post-construction oper- impact factor areas. In addition, the need to provide a ations is an emerging field. clean environment from both an air quality and water quality perspective could be included in an environ- Future Research Needs mental monitoring plan, as well as including pollution The following research needs were identified in prevention, climate protection, habitat preservation this chapter: and aesthetics (Ramani et al. 2009). 10

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Recycling, reusing, and reclaiming of existing level of alternative material usage in agency pavement materials is crucial to advance sustainable develop- preservation and maintenance programs in Canada ment (Carpenter and Gardner 2007). Construction and the United States. Table 5 shows that alternative materials can be expensive and now some resources materials have a lower level of use than recycled are in limited supply, making it important to make materials, probably awaiting further research into good use of available materials. One of the concerns their long-term performance in maintenance applica- with the use of recycled material is potential uncer- tions. Table 5 reflects the relatively widespread use of tainty regarding the actual composition of a recycled fly ash in concrete, as well as asphalt shingles and material when compared with the virgin material it recycled rubber tires in hot-mix asphalt pavements. would replace. As a result, some agencies have with- However, the use of other alternative materials held permission to use recycled materials, whereas remains relatively uncommon. These results suggest others have limited the amount of recycled material that future research into applications and performance that can be incorporated into the pavement structure of alternative materials could be of value. (Melton and Morgan 1996; Smith and Romine 2009). Minimizing or eliminating noise pollution is Several successful uses of recycled asphalt pavement another element of a sustainable design and con- and recycled concrete aggregate are available in the struction program, and it follows that standards literature and it can be noted that in addition to pro- imposed on construction may also be applicable to viding technical benefits, they improve the perfor- maintenance operations. Table 6 shows the results mance of the pavement (Beatty et al. 2002; Alkins of that portion of the survey. Only about 21% of the et al. 2008; Tighe et al. 2008; Smith and Tighe 2009; respondents believed that noise pollution is an impor- Scholz 2010). Further, both hot and cold in-place recy- tant/very important issue in their agencies. Only 7% cling are used by agencies for maintenance and reha- were aware of noise standards for their agencies' bilitation of pavements, minimizing the amount of pavement maintenance operations, whereas more than new materials for the work and reducing energy one-third of the survey respondents did not have any requirements for transporting materials to the job site. noise standards for maintenance operations. Relevant Table 4 shows that roughly 70% of the responding future research could help establish appropriate noise agencies permit the use of recycled materials in their standards for construction and maintenance opera- pavement preservation and maintenance programs. tions, and provide a tool for using noise considerations Alternative materials also hold the promise as part of treatment selection. As noted by the high of being able to enhance environmental sustainability number of respondents choosing the "no opinion" or in pavement preservation and maintenance. Research "don't know" categories, it could be suggested that has shown that materials such as recycled asphalt education and training be provided in this environ- shingles, recycled rubber tire, recycled glass, and mental sustainability impact factor area for mainte- reclaimed carbon from copier toner can be success- nance personnel. fully incorporated into new pavements (Chan and For the environmental sustainability factor of Tighe 2010). The incorporation of innovative materi- water quality, there is a similar unfamiliarity among als can also potentially enhance pavement perfor- the survey respondents about how agency policies are mance and reduce the demand for virgin materials applied to maintenance activities. Based on this eval- (Horvath 2004). Thus, the survey sought to find the uation, there are no current measures available that Table 4 Summary of recycled and alternative materials authorization Are Recycled Materials Allowed Are Alternative Materials Allowed in Your Current Program? in Your Current Program? No Yes No Yes Canada 0 7 2 5 U.S. 14 28 18 24 Total 14 35 20 29 Percentage 28.6 71.4 40.8 59.2 11

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TABLE 5 Summary of recycled and alternative material usage by pavement type Gravel Surface Treated Asphalt Recycled/Alternative Material Canada U.S. Canada U.S. Canada U.S. Fly Ash 0 0 0 1 1 0 Shingles 0 1 0 1 2 13 Tire Rubber 0 1 0 1 2 13 Glass 0 2 0 0 0 3 Foundry Sand 0 0 0 0 0 1 Carbon 0 0 0 0 0 1 Concrete Composite Recycled/Alternative Material Canada U.S. Canada U.S. Total Percentage Fly Ash 4 21 0 1 28 57.1 Shingles 0 0 0 0 17 34.7 Tire Rubber 0 0 0 0 17 34.7 Glass 0 1 0 0 6 12.2 Foundry Sand 0 2 0 0 3 6.1 Carbon 0 0 0 0 1 2.0 quantify the effects of pavement maintenance and indicates that coupling programmatic environmental preservation on water quality. The data indicate that sustainability with pavement preservation and main- the pavement preservation and maintenance treat- tenance programs has not yet happened in North ment's impact on water quality is considered less America. Again, this would reinforce the need to than half the time, probably because less than half the develop measures in this area for quantification. responding agencies indicated that they have agency The news with regard to air quality is better. A water quality guidelines. That roughly one-third of little over 60% of the agencies reported that they all respondents did not know if their agency consid- monitor air quality in the course of their pavement ered water quality or had water quality guidelines maintenance operations. However, only 25% of Table 6 Summary of noise pollution measures How important is noise distribution during pavement maintenance operations in your agency? Agency Noise Standards in Effect Not Even Considered Construction Noise Maintenance Noise No Noise Standard Very Important Not Important Traffic Noise Don't Know No Opinion Important Neutral Canada 0 1 3 0 2 1 2 1 0 4 0 U.S. 4 4 12 0 4 11 7 2 3 11 15 Total 4 5 15 0 6 12 9 3 3 15 15 Percentage 9.5 11.9 35.7 0.0 14.3 28.6 21.4 7.1 7.1 35.7 35.7 12