prEN ISO 24576
(Main)Geosynthetic - Test method for determining the resistance of polymeric geosynthetic barriers to environmental stress cracking (ISO/DIS 24576:2017)
Geosynthetic - Test method for determining the resistance of polymeric geosynthetic barriers to environmental stress cracking (ISO/DIS 24576:2017)
This document specifies a test method for screening the resistance of polymeric geosynthetic barriers to stress cracking. The test is applicable to polyethylene based products which meets at least one of the following requirements:
- there is a pronounced yield point;
- density of the final product is > 0.939 g/cm3.
NOTE The described method is suitable for conformance testing of smooth surfaced (non-textured) geosynthetic barriers. However the resistance to stress cracking of the resin used in the manufacture of structured surface materials can be evaluated by carrying out the test where structuring is carried out as a separate processing step, on a preformed smooth surface geosynthetic barrier, the test can be performed on the intermediate smooth material.
The data are suitable for screening and determination of conformity but not for deriving performance data such as lifetime, unless supported by further evidence
Geokunststoffe - Prüfverfahren zur Bestimmung der Beständigkeit von geosynthetischen Kunststoffdichungsbahnen gegen umweltbedingte Spannungsrissbildung (ISO/DIS 24576:2017)
Géosynthétiques - Méthode déssai pour la détermination de la résistance des géomembranes polymériques à la fissuration sous contrainte environnementale (ISO/DIS 24576:2017)
Geosintetika - Preskusna metoda za ugotavljanje odpornosti polimernih geosintetičnih ovir proti razpokam zaradi okoliških napetosti
General Information
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Standards Content (Sample)
SLOVENSKI STANDARD
oSIST prEN 14575:2017
01-april-2017
*HRVLQWHWLND3UHVNXVQDPHWRGD]DXJRWDYOMDQMHRGSRUQRVWLSROLPHUQLK
JHRVLQWHWLþQLKRYLUSURWLUD]SRNDP]DUDGLRNROLãNLKQDSHWRVWL
Geosynthetics - Test method for determining the resistance of polymeric geosynthetic
barriers to environmental stress cracking
Geokunststoffe - Prüfverfahren zur Bestimmung der Beständigkeit von geosynthetischen
Kunststoffdichtungsbahnen gegen umweltbedingte Spannungsrissbildung
Géosynthétiques - Méthode d'essai pour la détermination de la résistance des
géomembranes polymériques à la fissuration sous contrainte environnementale
Ta slovenski standard je istoveten z: prEN ISO 24576
ICS:
59.080.70 Geotekstilije Geotextiles
oSIST prEN 14575:2017 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
oSIST prEN 14575:2017
oSIST prEN 14575:2017
DRAFT
EUROPEAN STANDARD
prEN 14576
NORME EUROPÉENNE
EUROPÄISCHE NORM
February 2017
ICS 59.080.70 Will supersede EN 14576:2005
English Version
Geosynthetics - Test method for determining the
resistance of polymeric geosynthetic barriers to
environmental stress cracking
Géosynthétiques - Méthode d'essai pour la Geokunststoffe - Prüfverfahren zur Bestimmung der
détermination de la résistance des géomembranes Beständigkeit von geosynthetischen
polymériques à la fissuration sous contrainte Kunststoffdichtungsbahnen gegen umweltbedingte
environnementale Spannungsrissbildung
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 189.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2017 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 14576:2017 E
worldwide for CEN national Members.
oSIST prEN 14575:2017
prEN 14576:2017 (E)
Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Principle . 5
4 Requirements . 5
4.1 Apparatus . 5
4.1.1 Blanking die . 5
5 Notch depth (0,2 × d). 6
5.1.1 Notching device . 6
5.1.2 Stress cracking apparatus . 7
5.2 Test temperatures . 8
5.3 Reagent . 8
5.4 Test duration . 8
5.5 Specimens . 8
5.5.1 Tensile test specimens . 8
5.5.2 NCTL-specimens . 9
5.6 Notching procedure . 10
5.6.1 Destructive notch depth evaluation . 10
5.6.2 Non-destructive notch depth evaluation . 10
5.7 Test procedure . 10
6 Test report . 11
Annex A (informative) Accelerated test method . 13
A.1 Test temperature . 13
A.2 Reagent . 13
Bibliography . 14
oSIST prEN 14575:2017
prEN 14576:2017 (E)
European foreword
This document (prEN 14576:2017) has been prepared by Technical Committee CEN/TC 189
“Geosynthetics”, the secretariat of which is held by NBN.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 14576:2005.
oSIST prEN 14575:2017
prEN 14576:2017 (E)
Introduction
Stress cracking is a phenomenon observed in most thermoplastic materials. It is defined as internal or
external cracking of the material caused by tensile stresses less than the short time mechanical strength
of the material. Stress cracking may limit the durability of e.g. geosynthetic barriers. In addition to the
influence of the stress, stress cracking is accelerated by elevated temperature and the presence of
certain molecular species, such as surfactants, in the surrounding environment.
The ability of a material to withstand stress cracking is known as its stress crack resistance. Stress crack
resistance is measured by the time required to failure when a specimen of the material is immersed in a
particular medium at elevated temperature while under a defined stress. Stress crack resistance is
primarily a function of the resin (thermoplastic raw material) type but may be adversely influenced by
the geosynthetic barrier manufacturing process particularly certain procedures for friction
enhancement.
To meet the requirement to accurately quantify and differentiate the performance of modern resins the
Geosynthetics Institute (formerly Geosynthetics Research Institute) developed an alternative method
GRI-GM5. The GRI method is frequently referred to as the “notched constant tensile load” (NCTL) test as
the apparatus used ensures a constant level of stress in the specimen throughout the test and the
specimen is notched to provide a concentration point for stress and failure. The NCTL test is used
extensively throughout the geosynthetic barrier industry.
The NCTL test can be performed under two separate procedures that are described in GRI-GM 5(a) and
5(b). In the procedure GRI-GM 5(a), the so-called “full curve test”, specimens are immersed in the test
liquid at a range of stresses, typically from 20 % to 65 % of the yield stress of the material. The time to
failure and the failure mode (brittle or ductile) is recorded at each level of stress. Failure time is plotted
against stress. Typically the resulting curve will show an abrupt change in slope at a point that coincides
with a change in failure mode. The time at which this occurs is recorded as the “transition time”.
The second variant of the test, GRI-GM 5(b), which is simpler and quicker to perform, is known as the
“single point” test. In this case the specimens are tested at 30 % of the measured yield stress of the
material at normal room temperature, and the time to failure is recorded. The procedure described in
this document is based on GRI-GM 5(b).
oSIST prEN 14575:2017
prEN 14576:2017 (E)
1 Scope
This European Standard specifies a test method for screening the resistance of polymeric geosynthetic
barriers to stress cracking. The test is applicable to polyethylene based products which meets at least
one of the following requirements:
— there is a pronounced yield point;
— density of the final product is > 0,939 g/cm3.
NOTE The described method is suitable for conformance testing of smooth surfaced (non-textured)
geosynthetic barriers. However the resistance to stress cracking of the resin used in the manufacture of structured
surface materials can be evaluated by carrying out the test where structuring is carried out as a separate
processing step, on a preformed smooth surface geosynthetic barrier, the test can be performed on the
intermediate smooth material.
The data are suitable for screening and determination of conformity but not for deriving performance
data such as lifetime, unless supported by further evidence
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
EN ISO 527-3, Plastics - Determination of tensile properties - Part 3: Test conditions for films and sheets
(ISO 527-3)
EN ISO 9862, Geosynthetics - Sampling and preparation of test specimens (ISO 9862)
EN ISO 9863-1:2016, Geosynthetics - Determination of thickness at specified pressures - Part 1: Single
layers (ISO 9863-1:2016)
3 Terms and definitions
Not applicable.
4 Principle
Dumbbell shaped notched NCTL-specimens cut from the polymeric geosynthetic barrier are subjected
to a constant tensile load in the presence of a surface-active agent at an elevated temperature. The time
to failure of each NCTL-specimen is recorded.
5 Requirements
5.1 Apparatus
5.1.1 Blanking die
A die suitable for cutting NCTL-specimens to the dimensions and tolerances is shown in Figure 1.
The length of the NCTL-specimen can be changed to suit the design of the test apparatus. However,
there should be a constant width neck section at least 13 mm long. The width of the neck section should
be (3,20 ± 0,02) mm. The tab widths may be enlarged to accommodate grommets of different sizes with
which to attach hooks for the purpose of loading.
oSIST prEN 14575:2017
prEN 14576:2017 (E)
Dimensions may be varied to suit equipment with the exception of the neck dimensions shown*
Key
d thickness
d hinge thickness (0,8 × d)
h
1 notch depth (0,2 × d)
Figure 1 — Dimensions (in millimetres) of NCTL-specimen - left: top view, right: side view
Other specimens may also be used in the test, provided that the parties involved mutually agree to the
changes and state the specific details in the final report.
For the application of the test in factory production control (FPC) the test specimen according to
Figure 1 is recommended.
5.1.2 Notching device
A device or machine that can produce a consistent hinge thickness shall be used.
The notch should consist of a single cut with a thin blade. There should be no removal of the NCTL-
specimen material. An evaluation of the depth produced by the notching device is absolutely necessary.
Different methods can be used for this evaluation: e.g. quenching a notched specimen in liquid nitrogen
and then fracturing it and then measuring the notch depth and the ligament thickness under a reflected
light microscope. In this case the notch depth can readily be measured by examining the fracture
surface. Or alternatively measuring the notch depth and the ligament thickness from both sides of the
NCTL-specimen under light microscope without destroying the specimen.
oSIST prEN 14575:2017
prEN 14576:2017 (E)
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