Click for next page ( 37


The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement



Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 36
36 CHAPTER FIVE BENEFITS AND BARRIERS BENEFITS oxide/nitrogen dioxide by 54%, and sulfur dioxide by 61% compared with the mill and overlay option. CIREAM also A number of advantages to using in-place recycling pro- reduces the typical curing time from about 1 to 2 weeks cesses are routinely cited in the literature. Survey questions for CIR to 2 days for CIREAM (Lane and Kazmierowski were included to assess state and contractor perceptions of 2005b). benefits. The most frequently cited benefit is a savings of virgin materials (Table 37). Other benefits include shorter lane closures, reduced fuel consumption, and reduced emis- sions. Potential cost savings with recycling are addressed in the following section. TABLE 37 STATE AND CONTRACTOR RESPONSES FOR TYPE OF SURFACE TREATMENT USED Question: Environmental Benefits: Indicate environmental benefits, which you have documented on your projects Surface Treatments Agency Responses AK, AR, CA, DC, DE, FL, GA, IA, ID, IL, KY, MD, MN, MO, MT, NC, NE, FIGURE 30 Environmental benefits from in-place recycling Saves Virgin Materials NV, NY, ONT, OR, UT, VT, WY reported by agencies and contractors. Percentages are based Reduces Fuel CA, DC, ID, KY, MN, NV, ONT, UT, VT on the total survey respondents. Consumption Reduces Emissions CA, DC, ID, MN, NV, ONT, UT, VT The agency and contractor responses were used to rank and summarize the benefits gained from in-place recycling Shortens Lane Closures CA, DC, FL, ID, IL, MN, NV, ONT, UT (Table 39). Other AZ, NV TABLE 39 Contractors noted benefits associated with in-place recy- BENEFITS FROM IN-PLACE RECYCLING cling more frequently than did state agencies (Figure 30). The agency written responses suggest that agencies sub- Benefits from In-Place Recycling Frequency of Benefit jectively assume that benefits are achieved, but they do not Saves new materials Frequently specifically measure the benefits (Table 38). On the other Shortens lane closure times Often* hand, contractors provided a number of specific quantifiable Reduces fuel consumption Often* examples of environmental benefits. Reduces emissions Often* Additional information on environmental benefits was Rarely = lower than 10% average of agency and contractor with experience. Sometimes = between 10% and 25% average of agency and contractor with found in the literature. Alkins et al. (2008) reported that CIR experience. and CIR-expanded asphalt mixes (CIREAM) had twice the Often = between 25% and 50% average of agency and contractor with experience. production rate compared with the traditional mill and over- Frequently = greater than 50% average of agency and contractor with lay option, reducing traffic disruptions and worker exposure experience. *Contractor response was significantly higher than agency with experience. to traffic. These processes generate less noise and conserve natural resources by using recycled materials on the road- way. An evaluation of emissions using PaLATE found a Contractor project records can be used to provide quan- reduction in greenhouse gases. CIR and CIREAM programs tifiable environmental benefits from in-place recycling. in Ontario, Canada, reduced carbon dioxide by 52%, nitric Future research is needed to quantify benefits.