On season 2 episode 35 we discuss common nonconformities for the Standard Method of Test for Determining the Rheological Properties of Asphalt Binder Using a Dynamic Shear Rheometer (DSR) and how to resolve them.
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Printer Version: Top Nonconformities for AASHTO T 315 and ASTM D7175
SAMPLE PREP
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Nonconformity
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Resolution
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The sample was not covered to prevent contamination after being poured into the silicone mold.
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The laboratory must submit confirmation that technician and other staff have been retrained and have been observed preventing contamination in practice as described in the standards.
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TEMPERATURE
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Nonconformity
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Resolution
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The portable thermometer presented was not verified every 6 months at intervals of approximately 6°C over the range of test temperatures. The portable thermometer was verified every 12 months.
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The laboratory must submit a corrective action report along with records. The records must conform to AASHTO R 18, T 315, and ASTM D7175 requirements where appropriate. For example, calibration records for the reference thermometer must be provided by an ISO/IEC 17025-accredited calibration agency and include measurement uncertainty.
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Records of the verification of the temperature transducer of the rheometer, performed every 6 months, were not presented.
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PLATE DIAMETER
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Nonconformity
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Resolution
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The method specifies that the test plate diameters shall be measured to the nearest 0.01 mm and the smallest of the measured dimensions of the top and bottom plates shall be entered into the DSR software for use in the calculations. The test plates had been measured, but the measurements were not entered into the DSR software.
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These are procedural nonconformities must be resolved by retraining the technicians on the step(s) that were incorrectly performed. The laboratory must submit the records for checking the plates and show that the values have been entered into the software. All records must conform to the requirements of AASHTO R 18.
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The test plate diameter was not measured to the nearest 0.02 mm at three equally spaced locations approximately 120° apart. The test plate diameter was only measured at one location.
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