Every Day Is Earth Day for Asphalt
In time for Earth Day, NAPA and FHWA have released a new survey of sustainable construction practices in the asphalt pavement industry. The survey, which covers the 2011 construction season, studies the usage of reclaimed asphalt pavement (RAP), recycled asphalt shingles (RAS), and warm-mix asphalt (WMA). The use of recycled materials in asphalt pavements saved taxpayers more than $2.2 billion dollars during the 2011 paving season.
According to the survey, about 21.2 million barrels of liquid asphalt binder were saved through the use of RAP and RAS during 2011. Also, about 19 percent of all asphalt produced in the country that year was made using WMA.
In 2011, RAP usage reached 66.7 million tons, a 7 percent increase from 2010 and a 19 percent increase from 2009. More than 99 percent of asphalt pavement reclaimed from roads was collected for use in new pavements. In the survey, 98 percent of producers reported using RAP in their mixes for new construction, pavement preservation, rehabilitation, and other projects.
RAS usage also continued to climb, increasing to 1.2 million tons in 2011 — an 8 percent increase over 2010, and a 52.5 percent increase since 2009. Since 2009, RAS usage has been reported in 36 states. RAS includes both manufacturers’ scrap shingles and post-consumer roofing shingles.
In 2011, total WMA tonnage in the U.S. was estimated at about 69 million tons, a 67 percent increase from 2010 and a nearly 309 percent increase since 2009. Almost all WMA in the U.S. was produced using a foaming process; warm-mix additive technologies accounted for a little more than 4 percent of the market.
The survey was conducted in mid-2012. Results from 203 companies with 1,091 plants in 49 states and Puerto Rico, along with data from 32 State Asphalt Pavement Associations, were used to calculate industry estimates for total tonnage. A copy of the full survey, including a state-by-state breakdown of the data, is available at www.asphaltpavement.org/recycling.
Thin Is In for Pavement Preservation
Thin asphalt overlays are a popular approach to pavement preservation because of their ability to provide improved ride quality, reduce pavement distresses, maintain surface geometrics, reduce noise levels, reduce life-cycle costs, and provide long-lasting service. Recently, NAPA helped organize a thin asphalt overlay using warm-mix asphalt and recycled materials in Nashville, Tenn.
Tenth Street in downtown Nashville, an urban pavement with many utility cuts, was given 10 years more of life with this green (economically and environmentally) thin asphalt overlay preservation treatment. This is a NAPA instructional demonstration for those interested in asphalt paving processes and procedures. Mike Huner, Director of Technical Services for the Tennessee Road Builders Association, is the presenter. Special thanks go to the contractor, LoJac Enterprises Inc. of Lebanon, Tenn. The Tenth Street project was completed in August 2012. For more information on thin asphalt overlays, visit www.asphaltpavement.org/ThinIsIn.
NAPA Economic Study Finds Flaws in Material-Specific Discount Rates LCCA Proposal
The National Asphalt Pavement Association has released a report on life-cycle cost analysis procedures which examines in depth the concept of the material-specific discount rate. "Material-Specific Discount Rate: Inappropriate for Life-Cycle Cost Analysis" (NAPA Special Report 203) outlines standard and customary life-cycle cost analysis models. It also shines a light on a “material-specific discount rate,” which is being promoted by the cement and concrete industries.
NAPA’s report reveals that the material-specific discount rate is not a concept economists use or accept. Instead, it was suggested in a 2011 report as a computational work-around by the Concrete Sustainability Hub (CSH). The CSH, located at the Massachusetts Institute of Technology, is funded by the Portland Cement Association and the National Ready Mixed Concrete Association.
The CSH report is being used to support legislation in Congress mandating the use of a material-specific discount rate in life-cycle cost analyses when comparing alternative designs for publicly funded projects, including pavements, bridges, and buildings. If adopted, a material-specific discount rate could skew life-cycle cost analyses for construction materials, including asphalt, concrete, steel, wood, and plastics.
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