ASTM D6648-08

The temperatures for this test are based upon the winter temperature experienced by the pavement in the geographical area for which the asphalt binder is intended.

The flexural creep stiffness or flexural creep compliance, determined from this test, describes the low-temperature stress-strain-time response of asphalt binder at the test temperature within the range of linear viscoelastic response.

The low-temperature thermal cracking performance of asphalt pavements is related to the creep stiffness and the m-value of the asphalt binder contained in the mix.

The creep stiffness and the m-value are used as performance-based specification criteria for asphalt binders in accordance with Specification D 6373.

1.1 This test method covers the determination of the flexural-creep stiffness or compliance and m-value of asphalt binders by means of a bending beam rheometer. It is applicable to material having flexural-creep stiffness values in the range of 20 MPa to 1 GPa (creep compliance values in the range of 50 nPa^–1 to 1 nPa^–1) and can be used with unaged material or with materials aged using aging procedures such as Test Method D 2872 or Practice D 6521. The test apparatus may be operated within the temperature range from –36°C to 0°C.

1.2 Test results are not valid for test specimens that deflect more than 4 mm or less than 0.08 mm when tested in accordance with this test method.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.