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23 Table 6. Binders for validation of proposed new method for establishing mixing and compaction temperatures. Producer's Producer's Producer's Recommended Recommended Binder Reported Mixing Compaction Modification Crude I.D. Binder Grade Temperature Temperature Type Source W PG 82-22 345 325 SBS Venezuela X PG 70-28 308-315 279-285 Elvaloy North Sea Y PG 64-22 314-327 293-302 None Venezuela Z PG 76-22 347-353 317-322 SBS + Air Blown West Texas uate how the consistency of the binders affects mixing and com- mixture tests were used to establish relationships among tem- paction behavior. The mixture tests were a means to an end, the perature and coating, workability, and compactability. The end being an independent set of measurements on the coatabil- mixture experiments included ity and compactability to assess the predicted mixing and compaction temperatures from the candidate binder test meth- · Mix coating tests using a laboratory bucket mixer and a ods. Unless noted otherwise, all testing was conducted at the laboratory pugmill mixer. National Center for Asphalt Technology (NCAT) laboratory. · Mix workability tests with the Instrotek workability device. · Mix compaction tests using a specially equipped Pine Part 1: Binder Tests Instruments SGC model AFG1A (i.e., baby Pine). · Indirect tensile creep compliance and strength tests in accor- For each binder, a series of tests or experiments were used dance with AASHTO T 322. to characterize properties of the binder and evaluate changes in high temperature binder properties. These tests were per- Most of the mixture tests were based on a fine-graded Super- formed at temperatures that span typical mixing and com- pave mix design containing a blend of NCAT's lab standard paction temperatures used for asphalt mixtures. The binder granite aggregate. The mix design for this baseline mix is in- tests include the candidate procedures and additional tests to cluded in Appendix B. To further evaluate the effects of aggre- assess binder degradation. gate type, aggregate gradation, and RAP content, an additional The binder tests were compaction experiment was conducted with a subset of four binders. The subset of four binders selected for this mixture ef- · Viscosity measurements using AASHTO T 316 to estimate fects experiment were based on binders that exhibited dis- traditional equiviscous temperatures. tinctly different behaviors. A description of the mixtures used · Steady shear flow viscosity from a DSR extrapolated to in this subset of tests is shown in Table 7. Fine and coarse gra- higher temperatures. dations were to assess how aggregate particle size distributions · Viscosity at various shear rates from a rotational visco- affect mixing and compaction. The two aggregate types (gran- meter extrapolated to high shear rates. ite and gravel) are distinctively different with respect to texture, · Phase angle master curve from oscillation frequency sweeps shape, and absorption. Recycled asphalt pavement (RAP) also using a DSR. was included to evaluate the interaction of new asphalt and · Opacity (smoke) and mass loss measurements from the aged RAP binder. SEP test. · Binder grading in accordance with AASHTO M 320 and Multiple Stress Creep Recovery (MSCR) tests following Table 7. Mixture variations used in AASHTO TP 70 on binder samples before and after the SEP Compaction Experiment B. test to evaluate degradation. Aggregate Type Gradation Type RAP Content Granite Fine none Part 2: Mixture Tests Granite Fine 15% Granite Coarse 15% Mixture tests were included in the experimental plan to Gravel Fine 15% validate the predicted mixing and compaction temperatures from the candidate binder tests. For each of the study binders, Gravel Coarse 15%