scope:

This test method allows for the detection of coarse aggregates that have the potential to form expansive alkali-silica reaction (ASR) gels if used in concrete. This method represents a completely new approach. Unlike current standard tests like ASTM 1260, ASTM 1293, and T 380, this test method relies on purely chemical tests rather than measurement of the physical expansion of mortar and concrete specimens. No concrete or mortar specimens are required. The test is also conducted in a sealed environment inside a test tube which overcomes the alkali leaching problems of some current test methods. The test is completed in 21 days compared to 16 days for ASTM C1260, 56 days for T 380, and 365 days for ASTM C1293.

Units-The values stated in SI units are to be regarded as standard except for sieve sizes where the more familiar non-SI units are used.

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.