Impact of WMA Technology on the Use of RAP Mixtures in NC
https://apps.dot.state.nc.us/Projects/Research/ProjectInfo.aspx?ID=3082
Record Type: DOT
In the recent years, Recycled Asphalt Pavements (RAP) and Warm Mix Asphalt (WMA) have gained tremendous attention throughout the country. Research into these technologies is driven by their economic and environmental incentives. Many studies have proven the utility present in RAP recovered from construction sites and have shown that both aggregates and binder can be recycled for use in the construction of new asphalt pavements. WMA technology is relatively new as compared to RAP and it is being extensively researched in the United States after its success in Europe. For producing WMA, either a foamer device or additives like Sasobit® and synthetic zeolites are used to reduce the binder viscosity in order to lower mixing and compaction temperatures. The lower temperatures lead to lower energy consumption and emissions, creating a potential for WMA to reduce asphalt concrete production costs and carbon footprints. There has been speculation that use of WMA can lead to increased utilization of RAP. WMA technology deals with reducing the binder viscosity to facilitate mixing and compaction at lower temperatures. Thus, WMA used in conjunction with RAP (WMA-RAP) can lead to improved performance as well as increased usage of RAP. The potential cost reduction involved in utilizing two sustainable technologies may make contractors more willing to adopt higher percentages of RAP, even if it calls for reduction in binder grades. This study proposes to study the effect of using RAP in WMA. Various HMA and WMA mixtures, with and without RAP material, will be characterized with respect to fatigue life, resistance to permanent deformation, susceptibility to thermal cracking, and moisture susceptibility. The fatigue life and rut resistance of the mixtures will be evaluated by conducting dynamic modulus and flow number tests. The moisture-induced damage of the mixtures will be determined using the Tensile Strength Ration (TSR) as per AASHTO T-283 test procedure. Creep compliance obtained from the Indirect Tension Test will be used to characterize susceptibility of the mixtures to low temperature thermal cracking. A database of level 1 input for all the various mixtures will be developed for use in performance analysis using DARWin-ME. The study also proposes to conduct life cycle cost analyses to determine economy involved in using RAP material with WMA in asphalt concrete mixtures. Finally, the optimal type of mixture with the best possible combination of percentage RAP material and WMA technology for the North Carolina Department of Transportation (NCDOT) materials will be reported for use in the construction of new pavements.
Start date: 2012/8/16
End date: 2014/8/15
Status: Active
Contract/Grant Number: 2013-05
Total Dollars: 260000
Source Organization: North Carolina Department of Transportation
Date Added: 06/12/2012
Index Terms: Recycled materials, Warm mix paving mixtures, Tensile strength, Sasobit, Cracking, Moisture susceptibility, Pavement performance,
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North Carolina Department of Transportation
www.ncdot.org/doh/preconstruct/tpb/research/
Research and Development
1549 Mail Service Center
Raleigh, NC 27699-1549
USA
Phone: (919) 508-1790
Fax: (919) 715-0137
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Kadibhai, Mustansir A.
Phone: (919) 508-1819
Fax: (919) 715-0137
Email: mkadibhai@ncdot.gov
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North Carolina State University, Raleigh
Department of Civil Engineering, Campus Box 7908
Raleigh, NC 27695-7908
USA
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Tayebali, Akhtarhusein A.
Phone: (919) 515-7611
Fax: (919) 515-7908
Email: tayebali@eos.ncsu.edu
Khosla, N. P.
Phone: (919) 515-7835
Fax: (919) 515-7908
Email: khosla@eos.ncsu.edu
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