5.1 The critical strain energy release rate, J_c, is used to compare the cracking resistance of asphalt mixtures prepared with different binder and aggregate types prepared to meet the volumetric requirements of differing traffic levels tested at intermediate temperatures.

5.2 This engineering property is a performance indicator of intermediate temperature cracking.

Note 1: The quality of the results produced by this standard are dependent on the competence of the personnel performing the procedure and the capability, calibration, and maintenance of the equipment used. Agencies that meet the criteria of Specification D3666 are generally considered capable of competent and objective testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with Specification D3666 alone does not completely assure reliable results. Reliable results depend on many factors; following the suggestions of Specification D3666 or some similar acceptable guideline provides a means of evaluating and controlling some of those factors.

1.1 This test method covers the procedures for preparation, testing, and measurement of asphalt mixture cracking resistance at Long Term Pavement Performance (LTPP) database intermediate temperatures using semi-circular bend (SCB) geometry laboratory prepared or pavement core asphalt mix samples tested monotonically. The SCB sample is a half-disk with a notch cut parallel to the loading and vertical axis. The test method describes the determination of the critical strain energy release rate, J_c, and other parameters determined from the load-displacement curve. These parameters can be used to rank the resistance of asphalt mixtures to cracking.

1.2 The text of this standard references notes and footnotes which provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the standard.

1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.4 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.