ASTM C1604/C1604M-05(2019)

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.
Designation: C1604/C1604M − 05 (Reapproved 2019)
Standard Test Method for
Obtaining and Testing Drilled Cores of Shotcrete
This standard is issued under the fixed designation C1604/C1604M; 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 C174/C174M Test Method for MeasuringThickness of Con-
crete Elements Using Drilled Concrete Cores
1.1 This test method covers obtaining, preparing, and test-
C496/C496M Test Method for Splitting Tensile Strength of
ing cores drilled from shotcrete for length, compressive
Cylindrical Concrete Specimens
strength, or splitting tensile strength determinations.
C617/C617M Practice for Capping Cylindrical Concrete
1.2 The values stated in either inch-pound units or SI units
Specimens
shall be regarded separately as standard. SI units are shown in
C670 Practice for Preparing Precision and Bias Statements
brackets. The values stated in each system may not be exact
for Test Methods for Construction Materials
equivalents; therefore, each system must be used indepen-
C823/C823M Practice for Examination and Sampling of
dently of the other. Combining values from the two systems
Hardened Concrete in Constructions
may result in nonconformance with the standard.
C1140/C1140M Practice for Preparing and Testing Speci-
mens from Shotcrete Test Panels
1.3 The text of this standard references notes and footnotes
that provide explanatory material. These notes and footnotes C1231/C1231M Practice for Use of Unbonded Caps in
Determination of Compressive Strength of Hardened Cy-
(excluding those in tables and figures) shall not be considered
as requirements of the standard. lindrical Concrete Specimens
2.2 ACI Standards:
1.4 This standard does not purport to address all of the
318 Building Code Requirements for Structural Concrete
safety concerns, if any, associated with its use. It is the
506.2 Specification for Shotcreting
responsibility of the user of this standard to establish appro-
506.4R Guide for the Evaluation of Shotcrete
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
3. Terminology
1.5 This international standard was developed in accor-
dance with internationally recognized principles on standard-
3.1 For definitions of terms used in this standard, refer to
ization established in the Decision on Principles for the
Terminology C125.
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
4. Significance and Use
Barriers to Trade (TBT) Committee.
4.1 This test method provides standardized procedures for
obtaining cored specimens to determine the compressive
2. Referenced Documents
strength and splitting tensile strength of shotcrete during
2.1 ASTM Standards:
pre-construction, during construction, and from older shotcrete
C39/C39M Test Method for Compressive Strength of Cylin-
structures.
drical Concrete Specimens
4.2 Generally, test specimens are obtained in situ when
C42/C42M Test Method for Obtaining and Testing Drilled
doubt exists about the in-place shotcrete quality due either to
Cores and Sawed Beams of Concrete
low strength test results during construction or signs of distress
C125 Terminology Relating to Concrete and Concrete Ag-
in the structure. Other uses of this method are to provide
gregates
specimens for acceptance testing, construction control and to
assess the condition, quality and uniformity of the shotcrete in
This test method is under the jurisdiction of ASTM Committee C09 on
Concrete and ConcreteAggregates and is the direct responsibility of Subcommittee
accordance with Practice C823/C823M (see Note 1).
C09.46 on Shotcrete.
4.3 Specimens obtained by this method are used to verify
Current edition approved Dec. 15, 2019. Published December 2019. Originally
approved in 2005. Last previous edition approved in 2012 as C1604/
the thickness of shotcrete and aid in the visual assessment of
C1604M–05(2012). DOI: 10.1520/C1604_C1604M-05R19.
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
Standards volume information, refer to the standard’s Document Summary page on Available fromAmerican Concrete Institute (ACI), P.O. Box 9094, Farmington
the ASTM website. Hills, MI 48333-9094, http://www.concrete.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1604/C1604M − 05 (2019)
the shotcrete quality, workmanship, defects, shotcrete-to- 5.3 Grinding wheel, to trim and clean plain and fiber-
substrate bond and the condition of any reinforcement used in reinforced shotcrete specimens that conform to prescribed
the shotcrete. tolerances without significantly disturbing the aggregates, ma-
trix or fiber-reinforcement.
4.4 Shotcrete strength is affected by the location of the
shotcrete in a structure. Vertical, sub-horizontal and overhead
6. Sampling
elements of the shotcrete structure may show variability. Core
strength is affected by core orientation relative to direction of 6.1 General:
shotcrete application. These factors shall be considered in 6.1.1 Sampling shall be planned in accordance with the
planning the locations for obtaining shotcrete samples and in applicable provisions of Practice C823/C823M.The number of
samples, sample locations and sampling procedures shall be
interpreting strength test results.
established in the plan.
4.5 Shotcrete is applied in single or multiple layers, as plain
6.1.2 Shotcretesamplesobtainedfromtestpanelsshallbein
shotcrete, reinforced shotcrete, or fiber-reinforced shotcrete.
accordance with the applicable provisions of Practice C1140/
Core samples containing wire-mesh and reinforcing bars shall
C1140M.
not be used for compressive strength testing.
6.1.3 Samples of hardened shotcrete for use in the prepara-
4.6 Thestrengthofshotcreteisaffectedbymoisturecontent,
tion of strength test specimens shall not be taken until the
the specified moisture conditioning procedure for cores is
shotcrete is strong enough to permit sample removal without
intended to provide test specimens with reproducible moisture
disturbing the bond between the mortar, coarse aggregate (see
contents that minimize within-laboratory and between-
Note 3) and fiber-reinforcement. When preparing strength test
laboratory variations.
specimens from samples of hardened shotcrete, samples that
4.7 Sample acquisition may require a combination of core- havebeendamagedintheprocessofremovalshallnotbeused.
Specimens of defective shotcrete that cannot be tested shall be
drilling, sawing, and grinding that may have the potential to
adverselyaffectthesampleconditionifcareisnottakenduring reported as such if the defects are representative of the in-place
condition of the shotcrete (see ACI 506.4R).
sampling and testing.
4.8 A sampling plan shall be established that indicates the
NOTE 3—It is not possible to specify a minimum age when shotcrete is
strong enough to withstand damage during removal, because the strength
number of samples and their locations (see Note 1). The
at any age depends on the strength grade and curing of the shotcrete. If
acceptance criteria for shotcrete core strengths shall be estab-
accelerating admixtures are used during shotcrete application, core speci-
lished by the specifier of tests (see Note 2).
mens may be obtained for testing at approximately 6 h. If this is not
practical, removal of shotcrete can proceed if cored or cut surfaces do not
NOTE 1—Practice C823/C823M provides guidance on the development
display erosion of the mortar and the exposed coarse aggregate particles
ofasamplingplanforconcreteinconstructions.Anumberofmethodsthat
are embedded firmly in the mortar. Nondestructive test methods may be
supplement the examination of hardened shotcrete by means of represen-
usedtoestimatelevelofin-placestrengthdevelopmentpriortoattempting
tative core samples and testing are discussed in ACI 506.4R.
removal of shotcrete core samples (see ACI 506.4R).
NOTE 2—The core strength acceptance criteria cited in ACI 318 are
based on a comparison of molded cylinder specimens and cores. Shotcrete
6.1.4 Specimens containing embedded reinforcement shall
strengths are always based on core specimens, therefore the 85 % factor
not be used for determining compressive or splitting tensile
used in core to cylinder comparisons is not relevant to the evaluation of
strength.
shotcrete core strengths. A typical shotcrete specification reflecting stan-
dard industry practice is contained in ACI 506.2.
6.2 Core Drilling—Drill core specimens perpendicular to
the surface and avoid drilling near formed joints or edge
5. Apparatus
placement. Record the approximate angle between the drilled
5.1 Core Drill, for obtaining cylindrical core specimens core axis and the plane of the shotcrete as placed.
with diamond impregnated bits attached to a core barrel. The
core drill shall have a rigid mounting base and be capable of 7. Measuring the Length of Drilled Cores
being operated in any orientation normal to the shotcrete
7.1 Cores for determining the thickness of shotcrete layers
structurethatisbeingsampled.Thecoredrillshallbefreefrom
or other structural elements shall have a diameter of at least 3.0
excessive vibration when in operation and shall have sufficient
in. [75 mm] when the lengths of such cores are to be measured
torque and consistent rotational speed to sustain uniform rates
in accordance with Test Method C174/C174M.
of penetration of the core drill. The core barrel shall be cooled
7.2 Forcoresthatarenotintendedfordeterminingstructural
and core cuttings flushed with water during operation.
dimensions,measurethelongestandshortestlengthsonthecut
5.2 Saw, for cutting core specimens to size for compressive
surface along lines parallel to the core axis. Record the average
strength. The saw shall have a diamond or silicon carbide
length to the nearest ⁄4 in. [5 mm].
cutting edge and shall be capable of cutting plain and rein-
forced specimens in a single pass that conform with the
8. Cores for Compressive Strength
prescribed dimensions, without excessive heating or shock.
8.1 Diameter—The diameter of core specimens for the
determination of compressive strength in load bearing struc-
tural members shall be at least 3.0 in. [75 mm] (see Note 4).
Bartlett, F. M., and MacGregor, J. G., “Effect of Core Diameter on Concrete
Core diameters less than 3.0 in. [75 mm] shall be permitted as
Core Strengths,” ACI Materials Journal, Vol 91, No. 5, September–October 1994,
pp. 460–470. directed by the specifier of the tests.
C1604/C1604M − 05 (2019)
NOTE4—Thecompressivestrengthsof2-in[50-mm]diametercoresare
8.4 Sawing of Ends—The ends of core specimens to be
known to be somewhat lower and more variable than those of 3-in.
tested in compression shall be flat, and perpendicular to the
[75-mm] diameter cores. In addition, smaller diameter cores appear to be
longitudinal axis. If necessary, saw the ends of cores that will
more sensitive to the effect of the length-diameter ratio .
be capped so that the following requirements are met:
8.2 Length—The preferred length of the capped or ground
8.4.1 Projections, if any, shall not extend more than 0.2 in.
specimen is nominally two times the diameter.
[5 mm] above the end surfaces.
8.2.1 If the ratio of the length to the diameter (L/D) of the
8.4.2 The end surfaces shall not depart from perpendicular-
core exceeds 2.1, reduce the length of the core so that the ratio
ity to the longitudinal axis by a slope of more than 1:8d [or
of the capped or ground specimen is between 1.9 and 2.1. Core
1:0.3d], where d is the average core diameter in inches [or
specimens with length-diameter ratios equal to or less than
mm].
1.75 require corrections to the measured compressive strength
NOTE 6—This limitation is intended to avoid cap thicknesses that
(see. 8.8.1).Astrength correction factor is not required for L/D
exceed the requirements of Practice C617/C617M.
greater than 1.75. A core having a length of less than 95 % of
8.5 Capping—If the ends of the cores do not conform to the
its diameter before capping or a length less than its diameter
perpendicularity and planeness requirements of Test Method
after capping or end grinding shall not be tested unless so
C39/C39M, they shall be sawn or ground to meet those
directed by the specifyer of the tests.
requirements or capped in accordance with Practice C617/
8.2.2 For non-load bearing structural members or when it is
C617M. If cores are capped in accordance with Practice
impossible to obtain shotcrete cores with length-diameter ratio
C617/C617M, the capping device shall accommodate actual
(L/D) greater than or equal to 1.0, core specimens shall be
core diameters and produce caps that are concentric with the
subject to the approval of the specifier of the tests.
core ends. Measure core lengths to the nearest 0.1 in. [2 mm]
8.3 Moisture Conditioning—The following procedure is
before capping. Unbonded caps in accordance with Practice
intended to preserve the moisture of the drilled core and to
C1231/C1231M are not permitted.
provide a reproducible moisture condition that minimizes the
NOTE 7—Before capping, the density of a core may be estimated by
effects of moisture gradients introduced by wetting during
weighing it and dividing the mass by the volume calculated from the
drilling and specimen preparation.
average diameter and length.
8.3.1 The following procedure is used to obtain cores
8.6 Measurement—Before testing, measure the length of the
having a moisture condition that is representative of the
capped or ground specimen to the nearest 0.1 in. [2 mm] and
in-place shotcrete. After cores have been drilled, wipe off
use this length to compute the length-diameter (L/D) ratio.
surface water on the drilled core with a dry cloth and allow
Determine the average diameter by averaging two measure-
remaining surface moisture to evaporate. When surfaces ap-
ments taken at right angles to each other at the mid-height of
pear dry, but not later than 1 h after drilling, place cores in
the specimen. Measure core diameters to the nearest 0.01 in.
separate plastic bags or nonabsorbent containers and seal to
[0.2 mm] when the difference in core diameters does not
preve
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