【国外标准】 Standard Test Method for Determination of Relative Density and Absorption of Fine, Coarse, and Blended Aggregate Using Combined Vacuum Saturation and Rapid Submersion

4.1 Relative density (specific gravity) is the characteristic generally used for calculation of the volume occupied by the aggregate in various mixtures containing aggregate, including portland cement concrete, bituminous concrete, and other mixtures that are proportioned or analyzed on an absolute volume basis. Relative density (specific gravity) is also used in the computation of voids in aggregate in Test Method C29/C29M. Relative density (specific gravity) saturated surface dry (SSD) is used if the aggregate is at SSD, that is, if its absorption has been satisfied. Conversely, the relative density (specific gravity) oven dry (OD) is used for computations when the aggregate is dry or assumed to be dry.4.2 Apparent density and apparent relative density (apparent specific gravity) pertain to the solid material making up the constituent particles not including the pore space within the particles which is accessible to water.4.3 Absorption values are used to calculate the change in the mass of an aggregate due to water absorbed in the pore spaces within the constituent particles, when it is deemed that the aggregate has been in contact with water long enough to satisfy the absorption potential. The laboratory standard for absorption is that obtained after submerging dry aggregate for a prescribed period of time.NOTE 1: There are other test methods that have been used and continue to be used to determine these aggregate properties: Test Methods C127 and C128. This test method may result in values for these properties that are close to or divergent from values from other test methods.NOTE 2: The quality of the results produced by this standard are dependent upon the competence of the personnel performing the procedure and the capability, calibration, and the maintenance of the equipment used. Agencies that meet the criteria of Specification D3666 are generally considered capable of competent and objective testing, sampling, inspection, etc. Users of this standard are cautioned that compliance with Specification D3666 alone does not completely ensure reliable results. Reliable results depend on many factors; following the suggestions of Specification D3666 or similar acceptable guideline provides a means of evaluating and controlling some of those factors.1.1 This test method covers the determination of relative density and absorption of fine aggregates by Method A and coarse and blended aggregates by Method B.1.2 A multi-laboratory precision and bias statement for coarse and combined aggregate tests in this standard has not been developed at this time. Therefore, this standard should not be used for acceptance or rejection of coarse and combined aggregate materials for purchasing purposes.1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined. Some values have only SI units because inch-pound equivalents are not used in practice.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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.5 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.