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Expert Task Group on Asphalt Mixtures & Construction; Asphalt Binders; and Models Technology Agenda September 2000 Attachment F - Questionnaire on Dust to Binder Ratio for HMA
As a member of the Superpave Mix and Aggregate Expert Task Group, I have been asked to review the background on dust to binder specifications and the potential impact of this criteria being raised from 0.6 - 1.2 to 0.8 - 1.6 for some HMA mixtures. I am requesting your assistance with this matter by asking you or the appropriate person in your office to complete the short questionnaire enclosed with this letter. You may return the survey via mail or fax to the address/phone number listed above. I would appreciate your response by August 18, 2000. Thank you very much for your time and for sharing this information. Please feel free to call me if you have any questions.
Superpave Mix & Aggregate Expert Task Group Questionnaire On Dust to Binder Ratio or Dust Proportion (DP)
1 (a). Prior to implementation of Superpave, did your HMA specifications contain mix design limits for dust to binder ratio or a similar parameter? Yes: 23, No: 13
1 (b). If so, briefly describe or show the formula for the parameter? -200/total AC:15 -200/eff. AC:3
1 (c). What were the criteria (specified mix design limits) for the parameter? 0.6 to 1.2: 9
2 (a). Prior to implementation of Superpave, did your HMA specification contain mix production control limits for dust to binder ratio or a similar parameter? Yes: 11, No: 25
2 (b). If so, what were the criteria (specified production control limits) for the parameter? Same as design: 6
3 (a). If your state has implemented the Superpave system, does your specifications follow the
current AASHTO MP-2 and PP-28 for dust to binder ratio? Yes: 8, No: 16
3 (b). If your state has a different specification for dust to binder ratio, please identify your criteria. Responses Varied
4. Has there been any mix performance problems for mixtures produced outside of the original Superpave limits of 0.6 - 1.2? If so, please briefly describe the problem. Yes :6, No or none known: 24
5. Has there been any mix performance problems, attributed to DP, for mixtures produced within the new limits of 0.8 to 1.6? If so, please briefly describe the problem. Yes: 3, No or none known: 17
6. Please identify any research and/or documented experience, that has influenced your position or your specifications on the use of dust to binder ratio. None or left blank: 16, undocumented experience: 5
7. Please rate the importance of this issue in your state. Rate on a scale of 1 to 5, with 1 corresponding to not an issue, to 5 being a critical and controversial issue.