【国外标准】 Standard Test Method for Determining Cement Content of Fresh Soil-Cement (Heat of Neutralization Method) (Withdrawn 2024)

5.1 This procedure provides a means for reliably determining the cement content of soil-cement in approximately 15 to 20 min. The procedure can be used to determine the cement content of soil-cement to ±1 percentage point by mass of dry sample of the actual cement content, that is generally adequate for most construction control applications.5.2 The buffer solution reacts with the calcium hydroxide in the cement and may react with calcareous material in the soil to produce heat. Any reaction from calcareous soil is accommodated in the calibration curve but below 3 % cement content there is usually insufficient temperature reaction for reliable results. Because Class F pozzolan may not contain any calcium hydroxide for reaction, this test method will not determine percentage Class F pozzolan in the mix.NOTE 1: The quality of the result produced by this test method 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/ and the like. Users of this standard are cautioned that compliance with Practice D3740 does not in itself ensure reliable results. Reliable results depend on many factors; Practice D3740 provides a means of evaluating some of those factors.1.1 This test method covers the procedure for determining the cement content of fresh soil-cement. This test method can be used for determining the cement content of specimens that contain 3 to 16 % cement. This test method is appropriate for soil-cement containing up to 55 % plus 4.75 mm (No. 4) sieve-size particles with a maximum particle size of 75 mm (3 in.). It should not be used for determining the Class F pozzolan content of these mixtures.1.2 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026.1.2.1 The procedures used to specify how data are collected/recorded and calculated in this test method 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; it is common practice to increase or reduce significant digits of reported data commensurate with such considerations. It is beyond the scope of this test method to consider significant digits used in analysis methods for engineering design.1.3 Units—The values stated in SI units are to be regarded as the standard. The values given in parentheses are mathematical conversions to inch-pound units, which are provided for information only and are not considered standard. Reporting of test results in units other than SI shall not be regarded as nonconformance with this standard.1.3.1 The converted inch-pound units use the gravitational system of units. In this system, the pound (lbf) represents a unit of force (weight), while the unit for mass is slugs. The converted 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. As stated, 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 in lbm/ft3 shall not be regarded as nonconformance with this standard.1.4 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 and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Section 8.