ISO 24068-1:2021

INTERNATIONAL ISO
STANDARD 24068-1
First edition
2021-05
Building and civil engineering
sealants — Determination of the
degree of cure —
Part 1:
Build-up of tensile properties in
dumbbell-shaped specimens
Reference number
©
ISO 2021
© ISO 2021
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Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Apparatus and materials. 1
6 Conditioning . 2
7 Preparation of test specimen . 2
8 Test procedure . 3
9 Calculation and expression of test result . 3
9.1 Tensile stress . 3
9.2 Tensile strength . 3
9.3 Degree of cure . 4
9.4 Rounding of results . 4
10 Test report . 4
Bibliography . 6
Foreword
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This document was prepared by Technical Committee ISO/TC 59, Buildings and civil engineering works,
Subcommittee SC 8, Sealants.
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iv © ISO 2021 – All rights reserved

INTERNATIONAL STANDARD ISO 24068-1:2021(E)
Building and civil engineering sealants — Determination of
the degree of cure —
Part 1:
Build-up of tensile properties in dumbbell-shaped
specimens
1 Scope
This document specifies a method for the determination of the degree of cure of one- and multi-
component sealants as indicated by the build-up of the tensile properties in dumbbell-shaped specimens
during cure.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 37, Rubber, vulcanized or thermoplastic — Determination of tensile stress-strain properties
ISO 5893, Rubber and plastics test equipment — Tensile, flexural and compression types (constant rate of
traverse) — Specification
ISO 6927, Building and civil engineering sealants — Vocabulary
ISO 80000-1:2009, Quantities and units — Part 1: General
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 6927 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
4 Principle
The degree of cure of a dumbbell-shaped test specimen of a (ambient temperature curing) sealant
is determined as the ratio between the value of engineering tensile stress (secant modulus), or
maximum tensile strength at any time during cure, and the corresponding value measured after a
reference cure period.
5 Apparatus and materials
5.1 Tensile-testing machine with recording device, conforming to ISO 5893 (force class 2 as defined
in ISO 7500-1, corresponding to a maximum permissible value of accuracy of ±2 %). The accuracy class
for elongation shall be class D. An appropriate load cell of suitable sensitivity for the sealants to be tested
shall be used.
It shall be possible to set the tensile-testing machine at one or more of the following rates of displacement
of the driven grip: (100 ± 10) mm/min, (200 ± 20) mm/
...