This test method covers determination of the strains that are produced by causes other than externally applied forces and temperature changes in hardened hydraulic-cement paste, mortar, and concrete specimens tested in the laboratory and exposed to controlled temperature and moisture conditions. Autogenous strain and drying shrinkage strain are the two main components of total shrinkage of cementitious materials, and both can be measured with this test method. This test method allows the measurement of early-age strains immediately following final setting, which is important to accurately measure autogenous strains. The values stated in either inch-pound or SI units are to be regarded separately as standard. An exception is with regard to sieve sizes and nominal size of aggregate, in which the SI values are the standard, as stated in specification ASTM E11. Within the text, the inch-pound units are shown in parentheses. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other, without combining values in any way. The text of this standard refers to notes and endnotes that provide explanatory material. These notes and endnotes (excluding those in tables and figures) shall not be considered as requirements of the standard. 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. The quality of the results produced by this standard is 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.