AASHTO PP76:13(2020) Standard Practice for T roubleshooting Asphalt Specimen VolumetricI Differences between Superpave Gyratory Compactors (SGCs) Used in the Design and the Field Management of Superpave Mixtures

AASHTO PP76:13(2020) Standard Practice for T roubleshooting Asphalt Specimen VolumetricI Differences between Superpave Gyratory Compactors (SGCs) Used in the Design and the Field Management of Superpave Mixtures. 6.3.1. Laboratory-Prepared Mix—A mix similar to the anticipated production mix should he used. The mix should use the same asphalt hinder anticipated for production. One laboratory shall prepare sufficient mix for four SGC specimens per evaluation. Compact each SGC specimen to 115 ± 5 mm in height and 150 mm in diameter. (See Note 1.) Note 1—T 312 specimen tolerances are ±5 mm. Within this tolerance, all specimen final heights being within 2 mm of each other have been reported to improve correlation results. 6.3.1.1. The mixing temperature shall be determined according to T 312. 6.3.1.2. The laboratory-prepared mix shall be conditioned for volumetric mix design prior to compaction according to R 30. 6.3.2. Plant-Produced Mix—A mix similar to the anticipated production mix should be used. The mix should use the same asphalt binder anticipated for production. One sample shall be taken from a production haul vehicle, according to T 168, of sufficient size to fabricate four SGC specimens per evaluation. Compact each SGC specimen to 115 ± 5 mm in height and 150 mm in diameter. (See Note I.) 6.3.2.1. The production mixing temperature shall be recorded and compared to the recommended mixing temperature determined in Section 6.3.1.1. 6.3.2.2. Short-term conditioning is not required for plant produced mix. 6.4. The laboratory-prepared or production mix shall he split in accordance with T 168 and provided to each laboratory. Logistics in the laboratory may result in the cooling of mix samples prior to compaction. The cooling and reheating of asphalt mixes can affect the measured volumetric properties. Reheating of the mix is not part of the mix design as specified in R 35. Any differences in handling shall be recorded. If possible, an observer from either the specifying agency or contractor should assist in recording any within-procedure differences. 6.5. The mix shall be heated to the required temperature determined in Section 6.3.1.1. Heating may be performed in either the SGC mold or in a pan. The method employed by each laboratory and operator shall be the same and shall he recorded. In addition, the make and model of the OVCfl used shall he recorded. 6.6. Compact four specimens in each SGC according to T 312 to the design number of gyrations (N) anticipated for...