Asphalt Binder Aging Methods to Accurately Reflect Mixture Aging (2021) / Chapter Skim
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Pages 155-165
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From page 155... ...
155 Findings Short-Term Conditioning The primary concerns with AASHTO T 240 are: (1) binders of different consistencies could be treated differently because the film thickness and its renewal vary with the consistency of the binder, and (2)
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156 Asphalt Binder Aging Methods to Accurately Reflect Mixture Aging 5. Heating the binder and the containers before AASHTO T 240 conditioning increased the binder aging index about 6 percent.
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Figure 102. AASHTO T 240 online survey.
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158 Asphalt Binder Aging Methods to Accurately Reflect Mixture Aging Agency Tests per Year Binder Flow Susceptible Grades Percent Number 1 600 30 180 64-28, 70-22, 70-28. Both 70 grades are modified.
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Findings and Application 159 Agency Percent with Binder Flow Levelness Check Precoat Container Cool Horizontally 1 30 Every 6 months. Yes Yes 2 1 We calibrate it two times per year.
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160 Asphalt Binder Aging Methods to Accurately Reflect Mixture Aging Agency Percent with Binder Flow Issues with AASHTO T 240 1 30 2 1 Not much to complain. 3 0 We have a thermometer (LIG)
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Findings and Application 161 Long-Term Conditioning The primary improvement to AASHTO R 28 identified by the evaluation of long-term conditioning procedures was to increase the amount of aging simulated by the PAV to better match the properties of binders near the surface of the pavement after approximately 10 years in service. Feasibility experiments found novel approaches of using acoustic, sonic, and ultrasonic mixing to accelerate oxidation reactions were not successful; therefore, further development work investigated changing PAV operating parameters to accelerate aging.
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162 Asphalt Binder Aging Methods to Accurately Reflect Mixture Aging Based on the findings of the PAV operating parameters experiment, the long-term conditioning calibration experiment was conducted. The objective of this experiment was to determine appropriate conditioning temperatures for 12.5 g, 20-hour, 2.1 MPa PAV conditioning for various climates.
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Findings and Application 163 simulate production aging. The survey of highway agency technicians revealed users are generally satisfied with AASHTO T 240, but they would like to see additional improvement, primarily in the areas of temperature measurement, calibration, and binder recovery.
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164 Asphalt Binder Aging Methods to Accurately Reflect Mixture Aging for these binders was formed by heating the pan leveled to 0.00042 mm/mm under industrial nitrogen for 30 minutes at 135°C before PAV conditioning. If 12.5 g PAV conditioning is to be adopted, PAV equipment should be modified and automated to allow this coating step to be performed automatically.
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From page 165... ...
Findings and Application 165 in the AASHTO re:source proficiency sample testing, is 78.18 kPa (11.34 psi)
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