ASTM D7981-20 PDF Download

ASTM D7981-20 is a standard practice that describes the compaction of prismatic asphalt specimens using the Shear Box Compactor (SBC). The compacted specimens obtained through this practice can be used for various testing purposes, including bulk specific gravity, dynamic modulus, flow number, flow time, and fatigue performance characteristics. The dimensions of the specimens should be within a maximum width, length, and height of 150 mm, 450 mm, and 185 mm, respectively. The maximum height of the specimen depends on the mix type, target air voids, and equipment limitations.

There are two important notes mentioned in the standard practice. Note 1 highlights that the aggregate orientation in the specimens produced by this method may be different from samples produced by other laboratory compaction methods. Therefore, it is important to consider this difference when comparing the mechanical test results obtained from different compaction methods.

Note 2 emphasizes that the quality and reliability of the results obtained through this standard practice depend on the competence of the personnel performing the procedure and the capability, calibration, and maintenance of the equipment used. Compliance with Specification D3666 is recommended as it provides guidelines for evaluation and control of various factors affecting the reliability of test results. However, it is important to note that compliance with Specification D3666 alone does not guarantee reliable results.