ASTM C661-98

Standard Test Method for Indentation Hardness of Elastomeric-Type Sealants by Means of a Durometer

SCOPE
1.1 This test method describes a laboratory procedure for determining indentation hardness of joint sealing compounds, (single- and multicomponent), intended for use in building construction.  
1.2 The values stated in SI units are to be regarded as the standard. The values in parentheses are for information only.  
1.3 This standard does not purport to address the safety problems 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.

General Information

• Status: Historical
• Publication Date: 09-May-1998
• ICS: 83.060 - Rubber
• ICS: 91.100.50 - Binders. Sealing materials
• Technical Committee: C24 - Building Seals and Sealants
• Drafting Committee: C24.20 - General Test Methods

Relations

• Replaced By: ASTM C661-06 - Standard Test Method for Indentation Hardness of Elastomeric-Type Sealants by Means of a Durometer
• Effective Date: 01-Jan-2006
• Referred By: ASTM C1193-16(2023) - Standard Guide for Use of Joint Sealants
• Effective Date: 10-May-1998
• Referred By: ASTM C1021-08(2023) - Standard Practice for Laboratories Engaged in Testing of Building Sealants
• Effective Date: 10-May-1998
• Referred By: ASTM C1184-23 - Standard Specification for Structural Silicone Sealants
• Effective Date: 10-May-1998
• Referred By: ASTM C920-18 - Standard Specification for Elastomeric Joint Sealants
• Effective Date: 10-May-1998
• Referred By: ASTM D5893/D5893M-16(2021) - Standard Specification for Cold-Applied, Single-Component, Chemically Curing Silicone Joint Sealant for Portland Cement Concrete Pavements
• Effective Date: 10-May-1998
• Referred By: ASTM C1311-22 - Standard Specification for Solvent Release Sealants
• Effective Date: 10-May-1998
• Referred By: ASTM C1369-19 - Standard Specification for Secondary Edge Sealants for Structurally Glazed Insulating Glass Units
• Effective Date: 10-May-1998

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:C661–98
Standard Test Method for
Indentation Hardness of Elastomeric-Type Sealants by
Means of a Durometer
This standard is issued under the fixed designation C 661; 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.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope 5.2 Rectangular Brass Frame, with inside dimensions 130
1 1
by 40 by 6 mm (approximately 5 by 1 ⁄2 by ⁄4 in.).
1.1 This test method describes a laboratory procedure for
5.3 Aluminum Plates, two 16 to 24 gage, 80 by 150 mm
determining indentation hardness of joint sealing compounds,
(approximately 3 by 6 in.).
(single- and multicomponent), intended for use in building
5.4 Thin-Bladed Knife.
construction.
5.5 Metal Straightedge.
1.2 The values stated in SI units are to be regarded as the
standard. The values in parentheses are for information only.
6. Standard Test Conditions
1.3 This standard does not purport to address the safety
6.1 Unless otherwise specified by those authorizing the
concerns, if any, associated with its use. It is the responsibility
tests, standard conditions for test are room temperature: 23 6
of the user of this standard to establish appropriate safety and
2°C (73.4 6 3.6°F) and 50 6 5 % relative humidity.
health practices and determine the applicability of regulatory
limitations prior to use.
7. Procedure
7.1 Test for Hardness of Multicomponent Sealants:
2. Referenced Documents
7.1.1 Condition at least 250 g of base compound and
2.1 ASTM Standards:
2 appropriate amounts of curing agent for at least 24 h at
C 717 Terminology of Building Seals and Sealants
standard conditions; then mix the components thoroughly for 5
D 2240 Test Method for Rubber Property—Durometer
3 min.
Hardness
7.1.2 Fill the brass frame, after centering it on the aluminum
3. Terminology plate, with a portion of the conditioned compound and strike it
off flat with a metal straightedge. Lift the frame from the
3.1 Definitions—See Terminology C 717 for applicable
sealant after separating it by running a thin-bladed knife along
definitions of the following terms: compound, elastomeric,
the inside of the frame. Prepare two such specimens and cure
hardness, joint, non-sag sealant, self-levling sealant.
them for 14 days at standard conditions.
4. Significance and Use
NOTE 1—In the case of a self-leveling sealant or compound, do not lift
4.1 The results obtained by this test method are simply a
the brass frame until the sealant is sufficiently cured so that it will not
spread on the plate.
measure of the indentation into the sealant material of the
indentor under load; they are not generally considered a
7.1.3 At the end of the curing period, take three hardness
measure of abrasion or wear resistance of the sealant.
readings on each specimen at standard conditions. Hold the
durometer on the surface of the specimen and press it firmly
5. Apparatus
against the surface using a force of about 1.3 kgf (3 lbf). Keep
5.1 Durometer, Type A-2, with a dial graduated in units from
the pressure foot parallel to the surface of the specimen. Take
0 to 100. (See Test Method D 2240 for a description of the
the instantaneous indentation reading immediately after mak-
indentor and a method of calibration of the durometer.)
ing firm contact between the pressure foot and the specimen.
After taking the first reading, shift the durometer (or specimen)
to a new position in order to avoid errors due to fatigue and
ThistestmethodisunderthejurisdictionofASTMCommitteeC24onBuilding
surface effects from the previous indentation. Take readings on
Seals and Sealants and is the direct responsibility of Subcommittee C24.20 on
General Test Methods.
smooth portions of the surface no closer than 13 mm ( ⁄2 in.)
Current edition approved May 10, 1998. Published August 1998. Originally
fromtheedgesofthesealantpatandalsonocloserthan25mm
published as C 661 – 70. Last previous edition C 661 – 93.
2 (1 in.) from each other. Note the individual values, each
Annual Book of ASTM Standards, Vol 04.07.
rounded off to the nearest unit on the scale.
Annual Book of ASTM Standards, Vol 09.01.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C661–98
NOTE 2—The highest precision in this test can be obtained when the
7.2.3 Cure the test specimens for a total of 21 days as
durometer is supported by a rigid stand and a dead weight is fastened
follows: 7 days at standard conditions; 7 days in a chamber
directly to the instrument with the center of gravity of the weight acting
controlled at 38 6 2°C (100 6 3.5°F) and 95 % relative
in line of the indentor point. A freely acting total deadweight load of
humidity; and 7 days at standard conditions.
approximately 1.3 kgf (3 lbf) has been found satisfactory for the testing of
various sealants (Fig. 1).
NOTE 4—The manufacturer may request combinations of temperature
NOTE 3—The values obtained in the test method described in 7.1.3 are
and relative humidity for curing purposes other than those specified,
known as “instantaneous” values. Occasionally a purchaser may request
provided that (1) the curing period is not longer than 21 days and (2) the
“delayed” values such as these taken aftera5or 10-s del
...