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Increasing the amount of reclaimed asphalt binder in pavement mixes potentially impacts the <br />quality and longevity of the asphalt pavement, so increasing the allowed reclaimed asphalt binder <br />in mixes needs to be done with consideration as RAP contents greater than 20 to 30 percent is <br />an emerging technology without much research conducted on long-term impacts to the pavement <br />quality. Nationally, multiple organizations are experimenting with increasing the reclaimed asphalt <br />binder content, and Eugene provided pavement samples for research to the Asphalt Pavement <br />Association of Oregon in 2013. <br />In Eugene, typical RAP materials result in a one-to-one replacement of the virgin asphalt cement <br />needed for a typical dense graded asphalt pavement used on residential and collector streets in <br />Eugene. Since the asphalt cement generally makes up about a quarter of the cost of asphalt <br />pavement, reducing the amount of virgin asphalt cement used has the potential to decrease <br />materials costs as well as conserving virgin resources. <br />Based on positive test results on pilot projects constructed in 2013 to increase RAP usage, <br />Eugene will continue to select projects to increase the reclaimed binder in asphalt pavements. <br />The Eugene specifications allows flexibility for the contractors to meet the increased binder <br />replacement value using RAP or a combination of RAP and reclaimed asphalt shingles (RAS) <br />depending on the availability of materials and capabilities of the plant. <br />By its nature, reclaimed asphalt binders are stiffer and pavements that contain higher contents of <br />reclaimed asphalt binders are more susceptible to cracking. To compensate for this potential, the <br />grade of virgin asphalt binder typically used for Eugene paving with higher than 30 percent binder <br />replacement was replaced with a “softer” binder that should better resist cracking. <br />Eugene Public Works continues to test the limits and increase the percentage of reclaimed binder <br />content in city streets. While staff are on the forefront of this technology, they’re proceeding with <br />caution and choosing projects on a case-by-case basis. Typically they choose streets with lower <br />traffic volumes in order to minimize the chances of unintended consequences. <br />Nearly 8,200 tons of RAP was used on 2017 capital paving projects, reducing the need for nearly <br />490 tons of asphalt cement and 7,800 tons of aggregate to be mined, refined, processed and <br />subsequently shipped to the pavement producers. Using warm mix asphalt with typical reclaimed <br />asphalt pavement content resulted in an estimated reduction of 675 MT COe compared to using <br />2 <br />hot-mix asphalt pavement with no reclaimed pavement on 2017 capital paving projects. <br />Funding Status and Forecast <br />In 2012, project costs were estimated for each street for the purpose of selecting streets to be <br />included in the bond measure. These cost estimates were based on the overall surface condition <br />of each street as described in the City’s Pavement Management System. A unit cost was assigned <br />to each street based on whether the street rehabilitation treatment was assumed to be a <br />reconstruct or an overlay. Approximately 18 months prior to construction, more detailed pavement <br />testing is conducted to determine specific treatments to each street based on the existing <br />pavement structure, subgrade soil conditions and traffic loading. Actual rehabilitation treatments <br />may be different than the original assumptions, requiring more, less or a combination of <br />rehabilitation techniques. <br />2017 Report to the SRRP Page 7 <br /> <br />