scope:

This method describes the determination of the loose uncompacted void content of a sample of fine aggregate. When measured on any aggregate of a known grading, void content provides an indication of that aggregate's angularity, sphericity, and surface texture compared with other fine aggregates tested in the same grading. When void content is measured on an as-received fine aggregate grading, it can be an indicator of the effect of the fine aggregate on the workability of a mixture in which it may be used.

Three procedures are included for the measurement of void content. Two use graded fine aggregate (standard grading or as-received grading), and the other uses several individual size fractions for void content determinations:

Standard Graded Sample (Method A)-This method uses a standard fine aggregate grading that is obtained by combining individual sieve fractions from a typical fine aggregate sieve analysis. See Section 9, Preparation of Test Samples, for the grading.

Individual Size Fractions (Method B)-This method uses each of three fine aggregate size fractions: (a) 2.36 mm (No. 8) to 1.18 mm (No. 16); (b) 1.18 mm (No. 16) to 600 μm (No. 30); and (c) 600 μm (No. 30) to 300 μm (No. 50). For this method, each size is tested separately.

As-Received Grading (Method C)-This method uses that portion of the fine aggregate finer than a 4.75-mm (No. 4) sieve.

See Section 5, Significance and Use, for guidance on the method to be used.

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

This standard does not purport to address all of the 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 its 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.