ASTM D5731-08
(Test Method)Standard Test Method for Determination of the Point Load Strength Index of Rock and Application to Rock Strength Classifications
Standard Test Method for Determination of the Point Load Strength Index of Rock and Application to Rock Strength Classifications
SIGNIFICANCE AND USE
The uniaxial compression test (see Test Method D 7012) is used to determine compressive strength of rock specimens. However, it is a time-consuming and expensive test that requires significant specimen preparation and the results may not be available for a long time after the samples are collected. When extensive testing and/or timely information is required for preliminary and reconnaissance information, alternative tests such as the point load test can be used to reduce the time and cost of compressive strength tests, when used in the field. Such data can be used to make timely and more informed decisions during the exploration phases and more efficient and cost effective selection of samples for more precise and expensive laboratory tests.
The point load strength test is used as an index test for strength classification of rock materials. The test results should not be used for design or analytical purposes.
This test method is performed to determine the point load strength index of rock specimens and, if required, the point load strength anisotropy index.
Rock specimens in the form of either core (the diametral and axial tests), cut blocks (the block test), or irregular lumps (the irregular lump test) are tested by application of concentrated load through a pair of truncated, conical platens. Little or no specimen preparation is required and can therefore be tested shortly after being obtained and any influence of moisture condition on the test data minimized. However, the results can be highly influenced by how the specimen is treated from the time it is obtained until the time it is tested. Therefore, it may be necessary to handle specimens in accordance with Practice D 5079 and to document moisture conditions in some manner in the data collection.
Note 1—The quality of the result produced by this standard is dependent upon the competence of the personnel performing it, and the suitability of the equipment and facilities used. Agencies that meet the c...
SCOPE
1.1 This test method covers the guidelines, requirements, and procedures for determining the point load strength index of rock. This is an index test and is intended to be used to classify rock strength.
1.2 Specimens in the form of rock cores, blocks, or irregular lumps with a test diameter from 30 to 85 mm can be tested by this test method.
1.3 This test method can be performed in either the field or laboratory. The test is typically used in the field because the testing machine is portable, little or minimal specimen preparation is required, and specimens can be tested within a short time frame of being collected.
1.4 This test method applies to medium strength rock (compressive strength over 15 MPa (2200 psi)).
1.5 This test method does not cover which type of specimen should be tested or whether anisotropic factors should be considered. The specifics of the point load test program need to be developed prior to testing and possibly even before sampling. Such specifics would be dependent on the intended use of the data, as well as possible budgetary constraints and possible other factors, which are outside the scope of this test method.
1.6 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D 6026.
1.7 The method used to specify how data are collected, calculated, or recorded in this standard is not directly related to the accuracy to which the data can be applied in design or other uses, or both. How one applies the results obtained using this standard is beyond its scope.
1.8 The values stated in the SI units are to be regarded as standard.
1.9 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.
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Designation:D5731 −08
Standard Test Method for
Determination of the Point Load Strength Index of Rock and
1
Application to Rock Strength Classifications
This standard is issued under the fixed designation D5731; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* 1.9 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 This test method covers the guidelines, requirements,
responsibility of the user of this standard to establish appro-
andproceduresfordeterminingthepointloadstrengthindexof
priate safety and health practices and determine the applica-
rock.This is an index test and is intended to be used to classify
bility of regulatory limitations prior to use.
rock strength.
1.2 Specimensintheformofrockcores,blocks,orirregular
2. Referenced Documents
lumps with a test diameter from 30 to 85 mm can be tested by 2
2.1 ASTM Standards:
this test method.
D653 Terminology Relating to Soil, Rock, and Contained
1.3 This test method can be performed in either the field or
Fluids
laboratory. The test is typically used in the field because the D2216 Test Methods for Laboratory Determination of Water
testing machine is portable, little or minimal specimen prepa-
(Moisture) Content of Soil and Rock by Mass
ration is required, and specimens can be tested within a short D3740 Practice for Minimum Requirements for Agencies
time frame of being collected. Engaged in Testing and/or Inspection of Soil and Rock as
Used in Engineering Design and Construction
1.4 This test method applies to medium strength rock
D5079 Practices for Preserving and Transporting Rock Core
(compressive strength over 15 MPa (2200 psi)).
Samples
1.5 This test method does not cover which type of specimen
D6026 Practice for Using Significant Digits in Geotechnical
should be tested or whether anisotropic factors should be
Data
considered.Thespecificsofthepointloadtestprogramneedto
D7012 Test Methods for Compressive Strength and Elastic
be developed prior to testing and possibly even before sam-
Moduli of Intact Rock Core Specimens under Varying
pling. Such specifics would be dependent on the intended use
States of Stress and Temperatures
of the data, as well as possible budgetary constraints and
E18 Test Methods for Rockwell Hardness of Metallic Ma-
possible other factors, which are outside the scope of this test
terials
method.
E122 Practice for Calculating Sample Size to Estimate,With
Specified Precision, the Average for a Characteristic of a
1.6 All observed and calculated values shall conform to the
Lot or Process
guidelines for significant digits and rounding established in
Practice D6026. 2.2 ISRM Standard:
3
Suggested Methods for Determining Point Load Strength
1.7 The method used to specify how data are collected,
calculated, or recorded in this standard is not directly related to
3. Terminology
theaccuracytowhichthedatacanbeappliedindesignorother
3.1 For definitions of terms used in this test method refer to
uses, or both. How one applies the results obtained using this
Terminology D653.
standard is beyond its scope.
3.2 Definitions of Terms Specific to This Standard:
1.8 The values stated in the SI units are to be regarded as
standard.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
1
ThistestmethodisunderthejurisdictionofASTMCommitteeD18onSoiland Standards volume information, refer to the standard’s Document Summary page on
Rock and is the direct responsibility of Subcommittee D18.12 on Rock Mechanics. the ASTM website.
3
Current edition approved Jan. 1, 2008. Published February 2008. Originally “Suggested Methods for Determining Point Load Strength”, International
approved in 1995. Last previous edition approved in 2007 as D5731 – 07. DOI: Society for Rock Mechanics Commission on Testing Methods, Int. J. Rock. Mech.
10.1520/D5731-08. Min. Sci. and Geomechanical Abstr., Vol 22, No. 2, 1985, pp. 51–60.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
D5731−08
3.2.1 diameter—D, for point load tests,thedimensionofthe be highly influenced by how the specimen is treated from the
specimen between the opposing conical, test platens when time it is obtained until the time it is tested. Therefore, it may
placed in the test machine be necessary to handle specimens in accordance with Practice
D5079andt
...
This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation:D5731–07 Designation: D 5731 – 08
Standard Test Method for
Determination of the Point Load Strength Index of Rock and
1
Application to Rock Strength Classifications
This standard is issued under the fixed designation D 5731; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This test method covers the guidelines, requirements, and procedures for determining the point load strength index of rock.
This is an index test and is intended to be used to classify rock strength.
1.2 Specimens in the form of rock cores, blocks, or irregular lumps with a test diameter from 30 to 85 mm can be tested by
this test method.
1.3 This test method can be performed in either the field or laboratory. The test is typically used in the field because the testing
machine is portable, little or minimal specimen preparation is required, and specimens can be tested within a short time frame of
being collected.
1.4 This test method applies to medium strength rock (compressive strength over 15 MPa (2200 psi)).
1.5 This test method does not cover which type of specimen should be tested or whether anisotropic factors should be
considered. The specifics of the point load test program need to be developed prior to testing and possibly even before sampling.
Such specifics would be dependent on the intended use of the data, as well as possible budgetary constraints and possible other
factors, which are outside the scope of this test method.
1.6 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice
D 6026.
1.7 The method used to specify how data are collected, calculated, or recorded in this standard is not directly related to the
accuracy to which the data can be applied in design or other uses, or both. How one applies the results obtained using this standard
is beyond its scope.
1.8 The values stated in the SI units are to be regarded as standard.
1.9 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.
2. Referenced Documents
2
2.1 ASTM Standards:
D 653 Terminology Relating to Soil, Rock, and Contained Fluids
D 2216 Test Methods for Laboratory Determination of Water (Moisture) Content of Soil and Rock by Mass
D 3740 Practice for Minimum Requirements forAgencies Engaged in the Testing and/or Inspection of Soil and Rock as Used
in Engineering Design and Construction
D 5079 Practices for Preserving and Transporting Rock Core Samples
D 6026 Practice for Using Significant Digits in Geotechnical Data
D 7012 Test Method for Compressive Strength and Elastic Moduli of Intact Rock Core Specimens under Varying States of
Stress and Temperatures
E 18 Test Methods for Rockwell Hardness of Metallic Materials
E 122 Practice for Calculating Sample Size to Estimate, With Specified Precision, the Average for a Characteristic of a Lot or
Process
2.2 ISRM Standard:
1
This test method is under the jurisdiction of ASTM Committee D18 on Soil and Rock and is the direct responsibility of Subcommittee D18.12 on Rock Mechanics.
Current edition approved Feb.Jan. 1, 2007.2008. Published April 2007.February 2008. Originally approved in 1995. Last previous edition approved in 20052007 as
D 5731 – 057.
2
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
---------------------- Page: 1 ----------------------
D5731–08
3
Suggested Methods for Determining Point Load Strength
3. Terminology
3.1 For definitions of terms used in this test method refer to Terminology D 653.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 diameter—D, for point load tests, the dimension of the specimen between the opposing conical, test platens when placed
in the test machine
3.2.2 point load strength anisotropy index— I , the
...
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