ASTM C470/C470M-23

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Designation: C470/C470M − 15 C470/C470M − 23
Standard Specification for
Molds for Forming Concrete Test Cylinders Vertically
This standard is issued under the fixed designation C470/C470M; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope*
1.1 This specification covers molds for use in forming cylindrical concrete specimens. The provisions of this specification include
the requirements for both reusable and single-use molds.
NOTE 1—Sizes included are molds having diameters from 50 mm [2 in.] to 900 mm [36 in.].
1.2 The text of this standard references refers to notes and footnotes that which provide explanatory material. These notes and
footnotes (excluding those in tables and figures) shall not be considered as requirements of the standard.
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 may not beare not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be
used independently of the other. Combining other, and the values from the two systems may result in non-conformance with the
standard. The inch-pound units are shown in brackets.shall not be combined.
1.4 The following safety hazards caveat pertains only to the test method described in this specification: 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.
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.
2. Referenced Documents
2.1 ASTM Standards:
C31/C31M Practice for Making and Curing Concrete Test Specimens in the Field
C33C33/C33M Specification for Concrete Aggregates
C125 Terminology Relating to Concrete and Concrete Aggregates
C192/C192M Practice for Making and Curing Concrete Test Specimens in the Laboratory
C1077 Practice for Agencies Testing Concrete and Concrete Aggregates for Use in Construction and Criteria for Testing Agency
Evaluation
This specification is under the jurisdiction of ASTM Committee C09 on Concrete and Concrete Aggregates and is the direct responsibility of Subcommittee C09.61 on
Testing for Strength.
Current edition approved Feb. 1, 2015June 1, 2023. Published March 2015July 2023. Originally approved in 1961. Last previous edition approved in 20092015 as
C470/C470M – 09. DOI: 10.1520/C0470_C0470M-15.15. DOI: 10.1520/C0470_C0470M-23.
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 the ASTM website.
*A Summary of Changes section appears at the end of this standard
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C470/C470M − 23
D256 Test Methods for Determining the Izod Pendulum Impact Resistance of Plastics
D570 Test Method for Water Absorption of Plastics
3. Terminology
3.1 Definitions:
3.1.1 For definitions of terms used in this test specification, refer to Terminology C125.
4. General Requirements
4.1 The following provisions apply to both reusable and single-use molds:
4.1.1 Molds shall be constructed in the form of right circular cylinders which stand with the cylindrical axis vertical and the top
open to receive the concrete. They shall be made of materials that do not react with concrete containing portland or other hydraulic
cements. They shall be watertight and sufficiently strong and tough to permit their use without tearing, crushing, or deforming.
NOTE 2—Reusable lids may be used on molds to reduce moisture loss.
4.1.2 Molds shall have a nominal inside height equal to twice the nominal inside diameter. The diameter of a mold, consisting of
the average of two measurements taken at right angles to each other at the top of the mold, shall not differ from the nominal
diameter by more than 1 %. The height, determined by averaging two measurements taken 180° apart, shall not differ from the
nominal height by more than 2 %. The planes of the top rim of the mold and the bottom shall be perpendicular to the axis of the
mold within 0.5 degrees—approximately equivalent to 3 mm in 300 mm [ ⁄8 in. in 12 in.]. No diameter of a mold shall differ from
any other diameter of the same mold by more than 2 % except that molds that fail to meet this requirement may be used when
the user is able to demonstrate that no diameter of hardened concrete specimen produced in a similar mold differs from any other
diameter on the same specimen by more than 2 % (see Note 3).
NOTE 3—Certain single-use molds may require the use of a special device such as a tube of heavy-gage metal around the mold during molding to maintain
the dimensional tolerances specified in 3.1.24.1.2.
4.1.3 The bottom inside surface of the mold shall not depart from a plane by more than 2 mm in 150 mm [ ⁄16 in. in 6 in.] (1 %
of the diameter of the mold).
5. Reusable Molds
5.1 Reusable molds are those which are designed to be used more than a single time. Reusable molds shall be made of
nonabsorptive materials, and constructed as either one piece or several pieces (see Note 4).
5.2 Reusable molds shall be provided with a closure or base on the lower end at right angles to the axis of the cylinder. Molds
may be single piece molds or made from castings with a separate detachable base plate or a base that is an integral part of the
sidewall. The mold shall be either coated or made of a material that will prevent adherence to the concrete. At the time of use,
molds shall not leak water. An inside fillet, if any, at the bottom of the side wall shall have an indentation around the circumference
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no more than 3 mm [ ⁄8 in.] in the vertical direction or no more than 5 mm [ ⁄16 in.] in the horizontal direction.
5.3 Reusable molds shall be tested for water leakage as described in 6.47.4, for resistance to damage as described in 6.3.17.3.1,
and for dimensional stability in accordance with 3.1.24.1.2 and 3.1.34.1.3 initially and after every 50 uses or every six months,
whichever comes first.
NOTE 4—Satisfactory molds can be made from lengths of steel tubing or pipe that is slit on one side parallel to the axis and fitted with a means of closing
the vertical slit as well as a means of attaching a base plate. The required dimensional tolerances must be maintained after slitting, clamping, and attaching
the base plate. Other nonabsorptive materials which have been used include iron, brass, steel, and various plastics. Although aluminum and magnesium
alloys have been used, some of these alloys may be reactive with cement constituents and are therefore unacceptable.
6. Single-Use Molds
6.1 Single-use molds are molds designed to be used once and discarded. They are permitted to be made of sheet metal, plastic,
suitably treated paper products, or other materials and shall conform to the requirements of this specification.
C470/C470M − 23
6.2 Physical Requirements—The molds as prepared for use shall comply with the following:
6.2.1 Water Leakage—When tested as described in Section 67, there shall be no visible leakage.
6.2.2 Absorptivity—When tested as described in Section 67, the absorption shall not exceed the values given in Table 1.
Intermediate values are proportional to the square of the height.
6.2.3 Elongation—When tested as described in Section 67, the elongation after test shall not exceed 0.2 % of height.
6.3 Single-use Plastic Molds—Molds shall conform to the following additional requirements when plastic is the predominant
material used in construction:
6.3.1 Wall Thickness—The side walls shall be of sufficient stiffness to meet the requirements of 3.14.1 (See Note 5).
NOTE 5—This can be achieved through sufficient side wall thickness alone, or in combination with a stiffened top.
6.3.2 Bottom Design—The bottom shall be designed so that it will be flush with the bottom of the sidewall within a tolerance of
2 mm [ ⁄16 in.]. An inside fillet, if any, at the bottom of the sidewall shall have an indentation around the circumference no more
1 3
than 4 mm [ ⁄8 in.] in the vertical direction or no more than 5 mm [ ⁄16 in.] in the radial direction. The bottom shall be of adequate
rigidity to prevent permanent deformation when specimens are molded in accordance with the applicable provisions of Practice
C31/C31M or C192/C192M.
6.3.3 Material—The mold manufacturer shall certify that: (1) the plastic material used in molds has a maximum water absorption
of less than 0.5 % in 24 h when tested in accordance with Test Method D570; (2) the plastic has an Izod impact toughness of at
least 117 J/m [2.2 ft lb/in.] of notch for a 4 mm [ ⁄8 in.] thick specimen tested in accordance with Test Methods D256; and (3) after
being held at 12-12 °C [10 °F] for 24 h, the plastic shall not fracture when subject to tapping and jarring that is judged to be typical
of what occurs when specimens are molded in accordance with the applicable provisions of Practice C31/C31M or C192/C192M.
6.4 Paper Molds—When paper or other potentially absorptive fiber material is used as the primary structural material in the
construction of the side walls or bottom of the mold, the mold shall conform to the following additional requirements:
6.4.1 Side Walls—The side walls of paper molds shall be made with a minimum of three plies having a combined thickness of
not less than 2 mm [0.070 in.]. Seams on the inside of the mold shall not be open by more than 2 mm [ ⁄16 in.].
NOTE 6—The minimum thickness of material used in side walls and bottoms is considered adequate for cylinders up to 150 mm [6 in.] in diameter. For
larger cylinders thicker material may be required to meet requirements of 3.14.1.
6.4.2 Bottom Caps—The bottom cap of the mold shall
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