【国外标准】 Standard Test Methods for Moisture-Density (Unit Weight) Relations of Soil-Cement Mixtures

5.1 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/D559M and D560/D560M.NOTE 1: Since these tests are used in conjunction with Test Methods D559/D559M and D560/D560M 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 3/4-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 3/4-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 3/4-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.1.1 These test methods cover the determination of the relationship between the water content and the density of soil-cement mixtures when compacted before cement hydration as prescribed.1.2 A 0.0333-ft3 [944-cm3] mold and a 5.50-lbf [24.5-N or mass of 2.5-kg] rammer dropped from a height of 12.0 in. [30.5 cm] are used and two methods, depending on soil gradation, are covered, as follows:  SectionsTest Method A, using soil material passing a No. 4 [4.75-mm] sieve. This method shall be used when 100 % of the soil sample passes the No. 4 [4.75-mm] sieve   8Test Method B, using soil material passing a 3/4-in. [19.0-mm] sieve. This method shall be used when part of the soil sample is retained on the No. 4 [4.75-mm] sieve. This test method may be used only on materials with 30 % or less retained on the 3/4-in. [19.0-mm] sieve   91.3 Units—The values stated in inch-pound units or SI units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard.1.3.1 The gravitational system of inch-pound units is used when dealing with inch-pound units. In this system, the pound (lbf) represents a unit of force (weight), while the unit for mass is slugs. The slug unit is not given, unless dynamic (F=ma) calculations are involved.1.3.2 It is common practice in the engineering/construction profession to concurrently use pounds to represent both a unit of mass (lbm) and of force (lbf). This implicitly combines two separate systems of units; that is, the absolute system and the gravitational system. It is scientifically undesirable to combine the use of two separate sets of inch-pound units within a single standard. This standard includes the gravitational system of inch-pound units and does not use/present the slug unit for mass. However, the use of balances or scales recording pounds of mass (lbm) or recording density in lbm/ft3 shall not be regarded as nonconformance with this standard.1.4 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026.1.4.1 The procedures used to specify how data are collected/recorded and calculated in this standard are regarded as the industry standard. In addition, they are representative of the significant digits that should generally be retained. The procedures used do not consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the user’s objectives; and it is common practice to increase or reduce significant digits of reported data to be commensurate with these considerations. It is beyond the scope of this standard to consider significant digits used in analysis methods for the engineering design.1.5 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.1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.