These tests determine the optimum water content and maximum density (unit weight) to be used for molding soil-cement specimens in accordance with Test Methods D559 and D560.

Note 1-Since these tests are used in conjunction with Test Methods D559 and D560 and the criteria referenced therein, the test differs in several aspects from Test Method D698. There are three main differences between this standard and Test Method D698. Firstly, this standard allows a maximum particle size of ¾-in. (19.0 mm) for a 4-in. (101.6-mm) mold while Test Method D698 allows a maximum particle size of ³/₈-in. (9.5-mm) for the same size mold. Secondly, this standard permits the material leftover after the water content specimen has been obtained to be mixed with the rest of the sample and reused for the next determination. Test Method D698 does not permit the material to be reused. Thirdly, this standard allows the material that is retained on the ¾-in. (19.0-mm) and passing the 3-in. (75-mm) to be discarded (scalping technique) and replaced with an equal mass of material that passes the ¾ -in. (19.0-mm) sieve and is retained on the No.4 (4.75-mm) sieve. Test Method D698 does not permit the scalp and replacement technique.

Note 2-The quality of the result produced by this standard is dependent on the competence of the personnel performing it, and the suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with Practice D3740 does not in itself assure reliable results. Reliable results depend on many factors; Practice D3740 provides a means of evaluating some of those factors.