scope:

This test method covers the determination of the interlayer shear strength of asphalt pavement layers using laboratory-prepared samples or core samples.

This test can be performed on 150-mm (6-in.) or 100-mm (4-in.) diameter specimens of asphalt pavement.

This test is applicable if the asphalt overlay layer and the base layer are both 50 ± 5 mm (2.0 ± 0.2 in.) thick. The total specimen thickness must not exceed 150 mm (6 in.). Layers may be saw cut to the recommended layer thickness.

This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all safety concerns associated with its use. It is the responsibility of the user of this procedure to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use.

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 R 18 are generally considered capable of competent and objective testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with R 18 alone does not completely assure reliable results. Reliable results depend on many factors; following the suggestions of R 18 or some similar acceptable guideline provides a means of evaluating and controlling some of those factors.