ISO 25619-1:2021

INTERNATIONAL ISO
STANDARD 25619-1
Second edition
2021-02
Geosynthetics — Determination of
compression behaviour —
Part 1:
Compressive creep properties
Géosynthétiques — Détermination du comportement en
compression —
Partie 1: Propriétés de fluage en compression
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 Test specimens. 2
4.1 Sampling . 2
4.2 Number and dimensions of test specimens . 2
4.3 Conditioning . 6
5 Normal compressive load method . 6
5.1 Principle . 6
5.2 Apparatus . 7
5.3 Procedure . 8
5.4 Calculations . 9
5.5 Test report .10
6 Combined normal and shear load method .11
6.1 Principle .11
6.2 Apparatus .11
6.3 Procedure .12
6.4 Calculations .13
6.5 Test report .14
Annex A (informative) Variations to the index test procedure for site-specific tests .16
Annex B (informative) Typical curves .17
Foreword
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iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 221, Geosynthetics, in collaboration with
the European Committee for Standardization (CEN) Technical Committee CEN/TC 189, Geosynthetics,
in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
This second edition cancels and replaces the first edition (ISO 25619-1:2008) which has been technically
revised.
The main changes compared to the previous edition are as follows:
— normative references have been updated;
— dimension and shape of the specimen for different types of geosynthetics have been introduced;
— calculation of the correct area for structure in which loading is resisted at defined points or at
defined lines have been introduced;
— the drawing of a test apparatus for compressive shear test that was not described in the test has
been deleted.
A list of all parts in the ISO 25619 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2021 – All rights reserved

INTERNATIONAL STANDARD ISO 25619-1:2021(E)
Geosynthetics — Determination of compression
behaviour —
Part 1:
Compressive creep properties
1 Scope
This document specifies index test methods for determining the compressive creep properties of
geosynthetic products. The test specimens are subjected either to normal compressive loading or to a
combination of normal compressive loading and shear loading.
The test method with a normal load only (see Clause 5) is the standard method.
The test method in which combined normal and shear loads are applied (see Clause 6) is intended for
products that are sensitive to shear failure, i.e. which have a columnar or cuspated structure.
The tests are carried out on dry specimens or on specimens immersed in water. The test is intended
to be carried out with the specimen immersed in water when any part of the geosynthetic product
contains a hydrophilic polymer.
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 554, Standard atmospheres for conditioning and/or testing — Specifications
ISO 3696, Water for analytical laboratory use — Specification and test methods
ISO 9862, Geosynthetics — Sampling and preparation of test specimens
ISO 9863-1, Geosynthetics — Determination of thickness at specified pressures — Part 1: Single layers
ISO 10318-1, Geosynthetics — Part 1: Terms and definitions
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 10318-1 and the following 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/
3.1
thickness
d
distance between the two rigid plates in contact with the specimen at any stage of the test
Note 1 to entry: See Figures 1 and 2.
Note 2 to entry: Thickness is measured in millimetres.
3.2
initial thickness
d
i
thickness (3.1) of the specimen under an applied normal stress of 2 kPa
Note 1 to entry: Initial thickness is measured in millimetres, in accordance with ISO 9863-1.
3.3
initial compressed thickness
d
thickness (3.1) measured 1 min after loading (normal loading) or 4 min after loading (combined normal
and shear loading)
3.4
total compressive strain
ε
time-dependent change in thickness (3.1)
Note 1 to entry: Total compressive strain is expressed as a percentage of the initial thickness, d .
i
3.5
compressive creep strain
ε
cc
time-dependant change in thickness (3.1) of a material subjected to a constant compressive load (after
reaching the initial compressed thickness (3.3), d , of the specimen)
Note 1 to entry: Compressive creep strain is expressed as a percentage of the initial compressed thickness, d .
3.6
compressive creep collapse
occurrence of a sudden increase in the speed of change of thickness (3.1) of a specimen subjected to a
constant compressive load
3.7
machine direction
MD
direction of manufacture of a geosynthetic product (the warp direction for woven geotextiles)
3.8
cross-machine direction
CMD
direction perpendicular to the direction of manufacture of a geosynthetic product (the weft direction
for woven geotextiles)
4 Test specimens
4.1 Sampling
Specimens shall be taken in accordance with ISO 9862.
4.2 Number and dimensions of test specimens
Cut two specimens from the test sample for each test load; a new specimen is required for each test.
Each specimen shall satisfy the following criteria with regard to dimensions:
— the specimen shall be square and have a minimum size of 100 mm × 100 mm (see Figures 1 and 2);
2 © ISO 2021 – All rights reserved

— if the specimen has a structure in which loading is resisted at defined points or areas, then the
loading plate shall cover at least three complete points or areas in both directions (see Figure 1 and
Figure 3 a);
— if the specimen has a structure in which loading is resisted at defined lines, then the specimen shall
have a minimum of three contact lines on top loading plate and at least four complete lines on the
fixed base plate(see Figure 2 and Figure 3 b);
— specimens shall be cut with the sides parallel in MD and CMD of the sample. MD and CMD direction
shall be indicated on the sample.
a) Plan view of the specimen, with indication of defined points or areas where loading is
resisted
b) Cross-section of the specimen
Key
d thickness of the specimen, in millimetres
a
100 mm minimum, or at least three contact points in each direction.
Figure 1 — Dimensions of general test specimen
a) Plan view of the specimen, with indication of defined lines where loading is resisted
b) Cross-section of the specimen
4 © ISO 2021 – All rights reserved

c) Plan view of the specimen, with structure in which loading is resisted at defined lines in
diagonal directions
Key
1 specimen width
2 representative width of the specimen
d thickness of specimen, in millimetres
a
100 mm minimum, or a minimum of three contact lines on the top plate and a minimum of four contact lines on
the base plate.
b
100 mm minimum, or a minimum of three ribs connecting each side to the perpendicular side, for each set of ribs.
Figure 2 — Size of specimen with a structure in which loading is resisted at defined lines in MD
or CMD direction, or with a structure in which loading is resisted at defined lines in diagonal
directions
a) Example for a specimen with a structure in which loading
...