4.1 The geologic characteristics and the intended use of the rock core samples determine the extent and type of preservation and transportation required. If engineering properties are to be determined for the core, it must be handled and preserved in such a way that the measured properties are not significantly influenced by mechanical damage, changes in chemistry, and environmental conditions of moisture and temperature, from the time that the core is recovered from the drill core barrel and until testing is performed. Drill core is also the sample record for the subsurface geology at the borehole location, and as such must be preserved for some period of time, in some cases indefinitely, for future geologic study or core showings for design or the bidding process.

4.2 This practice presents a selection of curatorial requirements and chain of custody procedures applicable to most projects. The requirements are given for a variety of rock types and core sizes and project types ranging from small to large and from noncritical to critical. Project specific objectives, site conditions, and schedules may require adoption of more conservative handling and curatorial procedures. Guidance is given for the selection of those specific requirements which should be followed for a given project.

Note 1: 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 facility used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing/sampling/inspection. Reliable results depend on many factors; Practice D3740 provides a means of evaluating some, but not all, of those factors.

1.1 These practices cover the preservation, transportation, storage, cataloging, retrieval, and post-test disposition of rock core samples obtained for geotechnical site characterization, investigations, explorations, and design purposes including for use in visual classification and laboratory testing.

1.2 These practices apply to all types and conditions of rock, but exclude ice and permafrost.

1.3 Limitations: 

1.3.1 These practices, while relevant in general, do not apply to those situations in which changes in volatile gas components, contamination components, contamination of the pore fluids, or stress relaxation are critical to the intended use for the core.

1.3.2 These practices apply in general to all core sizes, however, they are mainly written for common N to P size, 1-⁷/₈ in. (47.6 mm) to 3-³/₈ in. (85 mm), drill core samples. Larger core diameters will have their own special requirements, for example, the use of a forklift may be needed to handle the core samples and containers.

1.4 Units—The values stated in inch-pound units are to be regarded as standard, except as noted below. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. Reporting of test results in units other than inch-pound shall not be regarded as nonconformance with this test method.

1.4.1 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.

1.5 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026.

1.6 This practice offers a set of instruction for performing one or more specific operations. This document cannot replace education or experience and should be used in conjunction with professional judgement. Not all aspects of this practice may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this document be applied without consideration of a project's many unique aspects. The word “Standard” in the title of this document means only that the document has been approved through the ASTM consensus process.

1.7 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.

1.8 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.