Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures (2022) / Chapter Skim
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From page 85... ...
A-1 Introduction The purpose of this appendix is to present a discussion of how binder tests were selected for in-depth evaluation as potential fatigue specification tests for NCHRP Project 09-59, "Relating Asphalt Binder Fatigue Properties to Asphalt Mixture Fatigue Performance." Review of Current Binder Fatigue Tests The following paragraphs briefly describe a number of promising binder tests that have been proposed as fatigue specification tests. This is not intended to be a complete list but provides several examples of potential asphalt binder fatigue tests.
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A-2 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures The yield energy test is a binder strength test performed using the DSR. In this test, the energy required to cause yielding in an asphalt binder specimen is measured.
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Review of Existing Binder Fatigue Tests and Selection for Further Evaluation as Part of NCHRP 09-59 A-3 as a function of shear strain, as is used to determine yield energy (Gibson et al., 2012)
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A-4 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures this is a relatively new test procedure and the procedure recommended by researchers involved in developing the test is frequently revised. The procedure to be used in NCHRP 09-59 will be determined in consultation with researchers at North Carolina State University and the University of Wisconsin–Madison.
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Review of Existing Binder Fatigue Tests and Selection for Further Evaluation as Part of NCHRP 09-59 A-5 an indication of the inherent fracture toughness of the material. The slope of the plot gives the plastic work of fracture.
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A-6 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures became extremely large. The simple extension data show r2 values of 99% with both CTOD values, and the r2 values with the ALF cracking data are essentially identical to those for the CTOD data.
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Review of Existing Binder Fatigue Tests and Selection for Further Evaluation as Part of NCHRP 09-59 A-7 compared to 100 mm/min will produce results that differ significantly in their correlation to mixture fatigue performance, and the lower rate will make the test much easier to implement because it will then be possible to perform the test on commercially available equipment. The two test temperatures selected will allow a comparison of the DENT failure properties with temperature and other binder properties such as modulus, and it will also allow for the estimation of DENT properties at some standard reference condition.
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From page 92... ...
A-8 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures In Australia, asphalt binders are currently classified according to viscosity at 60°C. Other tests included in the specification (AS 2008 -- 1997)
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Review of Existing Binder Fatigue Tests and Selection for Further Evaluation as Part of NCHRP 09-59 A-9 devised to provide information on the fracture toughness of asphalt binders. The extended BBR test is similar to the standard method but involves testing after conditioning at the test temperature for extended periods of time -- 24 and 72 hours.
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A-10 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures 3. Correlation with performance.
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Review of Existing Binder Fatigue Tests and Selection for Further Evaluation as Part of NCHRP 09-59 A-11 Table A-7. Description of criteria for technical difficulty/ease of implementation.
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A-12 Relationships Between the Fatigue Properties of Asphalt Binders and the Fatigue Performance of Asphalt Mixtures and from several NCHRP 09-59 panel members that this test is in fact difficult and time consuming to perform and many people in the industry would react negatively to having it become a specification test. Selection of Final Asphalt Binder Tests The NCHRP 09-59 research team has emphasized from the beginning of the project -- even during writing the initial proposal -- that the funding and time allotted for the project was not adequate for the development, refinement, and validation of a completely new test procedure for evaluating the fatigue performance of asphalt binders.
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