scope:

This method covers the determination of the degree of particle coating in an asphalt mix on the basis of the percentage of coarse aggregate particles that are completely coated. Determination of the percentage of coated particles for varying mixing times may be used to establish the least mixing time required to produce satisfactory coating of the aggregate for a given set of conditions. This test method applies to mixtures containing aggregate of a nominal maximum aggregate size less than 38 mm (1¹/₂ in.).

The values stated in SI units are to be regarded as the standard.

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.