MODIFICATION OF THE ASPHALT INSTITUTE BITUMINOUS MIX MODULUS PREDICTIVE EQUATION (DISCUSSION)

The dynamic modulus test results for five bituminous mix types (crushed stone, gravel, slag, sand-low P sub 200, sand-high P sub 200) were compared with modulus values predicted by using the Asphalt Institute regression model. Results of this comparison showed an excellent correlation for crushed stone, which was the primary mix type in the model development. For other materials, slag and snad, the results were poor. A correction methodology was developed based on statistical methods to minimize the mean square error between the measured moduli and those predicted by using the model. The model parameter used as the means for correction was the percentage of asphalt content, chosen because it had been shown that the asphalt content range used in model development was narrower than the range encountered in the laboratory study and that, mathematically, it had the greatest effect on the resultant modulus of all the model variables. A unique, material-dependent constant was calculated for each of the five mix types in the study that would be subtracted from the actual asphalt content of the mix for calculating the modulus. A more desirable, generalized method for determining the correction constant was developed based on the difference between the Marshall optimum asphalt content and the actual asphalt content of the mix instead of relying on mix nomenclature (e.g., slag asphalt, sand asphalt). The correction scheme produced a correlation coefficient of 0.891 for all 1179 data points used in this study. This is an excellent result for practical engineering applications. (Author)

• Record URL:
  http://onlinepubs.trb.org/Onlinepubs/trr/1983/911/911-004.pdf
• Record URL:
  https://scholar.google.com/scholar_lookup?title=MODIFICATION+OF+THE+ASPHALT+INSTITUTE+BITUMINOUS+MIX+MODULUS+PREDICTIVE+EQUATION+(DISCUSSION)&author=J.+Miller&author=J.+Uzan&author=M.+Witczak&publication_year=1983
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• Supplemental Notes:
  • Publication of this paper sponsored by Committee on Characteristics of Bituminous Paving Mixtures to Meet Structural Requirements. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved
• Authors:
  • Miller, John S
  • Uzan, Jacob
  • Witczak, Matthew W
• Discussers:
  • Uddin, Waheed
• Publication Date: 1983

Media Info

• Media Type: Print
• Features: Figures; References; Tables;
• Pagination: pp 27-36
• Monograph Title: Asphalt materials, mixtures, construction, moisture effects and sulfur
• Serial:
  • Transportation Research Record
  • Issue Number: 911
  • Publisher: Transportation Research Board
  • ISSN: 0361-1981

Subject/Index Terms

• TRT Terms: Asphalt content; Bituminous mixtures; Crushed rock; Equations; Forecasting; Granulated slag; Gravel; Modulus; Sand
• Uncontrolled Terms: Modifications
• Subject Areas: Construction; Highways; Materials; I31: Bituminous Binders and Materials;

Filing Info

• Accession Number: 00390787
• Record Type: Publication
• ISBN: 0309035546
• Files: TRIS, TRB
• Created Date: Dec 30 1984 12:00AM