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Title: USE OF RECLAIMED ASPHALT PAVEMENT IN SUPERPAVE HOT-MIX ASPHALT APPLICATIONS
Accession Number: 00780172
Record Type: Component
Record URL: Availability: Transportation Research Board Business Office 500 Fifth Street, NW Find a library where document is available Abstract: Implementation of the Superpave mix design method has encouraged the use of coarser hot-mix asphalt (HMA) mixtures, which require tight control of both the overall gradation and the percent passing the 0.075-mm (No. 200) screen. There is some concern that use of reclaimed asphalt pavement (RAP) in Superpave mixtures may be seriously limited because stockpiles of RAP may have widely variable gradations as well as high percentages of minus 0.075-mm material. The possibility of splitting RAP stockpiles by using the coarser RAP fraction in a typical 12.5 mm below-the-restricted-zone Superpave gradation has been evaluated. The finer RAP fraction was used in an above-the-restricted-zone 12.5-mm Superpave gradation. Two sources of RAP (Georgia and Minnesota) were used so that a wide range of asphalt and aggregate properties would be represented. Screening the RAP allowed up to 40% of the coarse RAP fraction to be used and still meet below-the-restricted-zone Superpave gradation requirements. This was mainly due to the significant reduction in the finer aggregate fractions, especially the minus 0.075-mm material. The use of RAP in these mixtures resulted in a savings of between 18 and 25% in the required neat asphalt. A noticeable increase in mixture stiffness with as little as 15% RAP was observed. This change in mixture properties suggested that a softer grade of neat binder might be needed. A maximum of 15% of the fine RAP fraction was used to produce an acceptable above-the-restricted-zone Superpave gradation. The net savings in neat asphalt content was 25%. Little change was observed in tensile strengths because of the addition of this RAP fraction. However, there was a substantial increase in mixture stiffness at intermediate to warm temperatures. This increase was also observed as a 20% reduction in the asphalt pavement analyzer rut depth when RAP was used. The indirect tensile creep compliance decreased when RAP was added. Although there was little difference in compliance at -20 deg C, there were decreases of about 30 and 50% at -10 deg C and 0 deg C test temperatures, respectively.
Supplemental Notes: This paper appears in Transportation Research Record No. 1681, Hot-Mix Asphalt Mixtures.
Language: English
Corporate Authors: Transportation Research Board 500 Fifth Street, NW Authors: Stroup-Gardiner, MaryWAGNER, CPagination: p. 1-9
Publication Date: 1999
Serial: ISBN: 0309071070
Features: Figures
(5)
; References
(3)
; Tables
(9)
TRT Terms: Uncontrolled Terms: Subject Areas: Highways; Materials; I31: Bituminous Binders and Materials
Files: TRIS, TRB, ATRI
Created Date: Dec 2 1999 12:00AM
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