CEN/TS 14418:2005

SLOVENSKI STANDARD
01-marec-2006
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Geosynthetic barriers - Test method for the determination of the influence of freezing-
thawing cycles on the permeability of clay geosynthetic barriers
Geosynthetische Dichtungsbahnen - Prüfverfahren zur Bestimmung des Einflusses von
Frost-Tau-Wechselbeanspruchungen auf die Durchlässigkeit von geosynthetischen
Tondichtungsbahnen
Barrieres géosynthétiques - Méthode d'essai pour la détermination de l'influence de
cycles de gelée-dégel sur la perméabilité a l'eau des barrieres géosynthétiques
bentonitiques
Ta slovenski standard je istoveten z: CEN/TS 14418:2005
ICS:
59.080.70 Geotekstilije Geotextiles
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL SPECIFICATION
CEN/TS 14418
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
December 2005
ICS 59.080.70
English Version
Geosynthetic barriers - Test method for the determination of the
influence of freezing-thawing cycles on the permeability of clay
geosynthetic barriers
Barrières géosynthétiques - Méthode d'essai pour la Geosynthetische Dichtungsbahnen - Prüfverfahren zur
détermination de l'influence de cycles de gelée-dégel sur la Bestimmung des Einflusses von Frost-Tau-
perméabilité à l'eau des barrières géosynthétiques Wechselbeanspruchungen auf die Durchlässigkeit von
bentonitiques geosynthetischen Tondichtungsbahnen
This Technical Specification (CEN/TS) was approved by CEN on 3 April 2005 for provisional application.
The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit their
comments, particularly on the question whether the CEN/TS can be converted into a European Standard.
CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS available
promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the CEN/TS)
until the final decision about the possible conversion of the CEN/TS into an EN is reached.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
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EUROPÄISCHES KOMITEE FÜR NORMUNG
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© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 14418:2005: E
worldwide for CEN national Members.

Contents Page
Foreword .3
Introduction.4
1 Scope .5
2 Normative references .5
3 Terms and definitions.5
4 Principle.5
5 Reagent.5
6 Apparatus .6
7 Procedure .8
8 Calculation and expression of results.10
9 Test report .11
Bibliography.12

Foreword
This Technical Specification (CEN/TS 14418:2005) has been prepared by Technical Committee CEN/TC 189
“Geosynthetics”, the secretariat of which is held by IBN/BIN.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to announce this CEN Technical Specification: Austria, Belgium, Cyprus, Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland
and United Kingdom.
Introduction
This Technical Specification defines a method for testing the influence of freezing-thawing cycles on the
permeability of clay geosynthetic barriers. Such resistance is a requirement for many uses of these products.
The influence ratio is an indication of the behaviour of the product when exposed to repeated freezing and
thawing cycles in earth constructions. The permeability of saturated clay geosynthetic barriers may increase in
consequence of repeated freezing-thawing cycles.
This Technical Specification does not purport to address all of the safety problems, if any, associated with its
use. It is the responsibility of the user of this document to establish appropriate safety and health practices
and determine the applicability of regulatory limitations prior to use.
The current Technical Specification has not yet been widely validated. The organisation of interlaboratory-
tests to acquire more experience is recommended.
1 Scope
This Technical Specification specifies an index test to determine the influence ratio of freezing-thawing cycles
on the flux through saturated clay geosynthetic barriers.
This test is applicable to clay geosynthetic barrier products with a geotextile backing. It is not necessarily
applicable to clay geosynthetic barrier products with a geomembrane backing.
2 Normative references
The following referenced documents are indispensable for the application 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.
EN ISO 10320, Geotextiles and geotextile-related products – Identification on site (ISO 10320:1999)
EN ISO 3696, Water for analytical laboratory use – Specification and test methods (ISO 3696:1987)
3 Terms and definitions
For the purposes of this Technical Specification, the following term and definition applies.
3.1
influence ratio
ratio of the flux value of a specimen exposed to wetting-drying cycles and divided by the flux through an
unexposed reference specimen, expressed in percent
4 Principle
The flux through 100 mm diameter clay geosynthetic barrier specimens is determined with a flexible wall
permeameter both on specimens exposed to freezing-thawing cycles and on unexposed reference specimens.
Geosynthetic clay barrier samples of 300 mm x 300 mm are saturated under a pressure of (4 ± 0,2) kPa for 48
h at constant room temperature. After saturation, one sample is stored in the freezer at –5 °C for 24 h, while
the reference sample remains at normal room temperature. After the freezing period the first sample is
allowed to thaw at room temperature for 24 h. Then the samples are submerged again for 24 h at room
temperature. This freezing-thawing cycle is performed four times before cutting the test specimens.
The specimen is mounted in a flexible-wall permeameter, subjected to a cell pressure of 550 kPa and a back
pressure of 515 kPa for a period of 48 h. Flow is initiated using deionized water by raising the pressure on the
inlet side of the test specimen to 530 kPa. The flux is determined when inflow and outflow are approximately
equal (within ± 25 %).
NOTE This test does not provide a hydraulic conductivity value. Hydraulic conductivity can be determined in a similar
way, but requires knowledge of the thickness of the specimen. This test does not include procedures for thickness
measurement of the clay geosynthetic barrier or of its clay component.
5 Reagent
De-aired, de-ionized water shall be in accordance with EN ISO 3696 grade 3.
Water is used to permeate the test specimen and also to exert a back pressure on the test specimen. As the
flux can be substantially influenced by the nature of the test liquid, de-aired, de-ionized water shall be used in
this test method.
The water shall be de-aired as well as de-ionized. The water is usually de-aired by boiling, by spraying a fine
mist of water in a vessel connected to a vacuum source, or by forceful agitation of water in a container
connected to a vacuum source. The de-aired water shall not be exposed to air for prolonged periods to
prevent the dissolving of air back into water.
6 Apparatus
NOTE The apparatus used in this test method is commonly used to determine the hydraulic conductivity of soil
specimens. However, flux values measured in this test are typically much lower than those commonly measured for
natural soils. The leakage rate of the apparatus should be less than 10 % of the flux.
6.1 Hydraulic system
The system shall be designed to facilitate rapid and complete removal of free air bubbles from flow lines and
be capable of maintaining constant hydraulic pressures within ± 5 %. It may be one of the following types:
 method A: a constant head system, e.g. the system specified in ASTM D 5887:2003; provided it meets
the criteria specified in this method;
 method B: a falling head method;
 method C: a constant rate of flow.
Pressures shall be measured by any device of suitable accuracy, e.g. a pressure gage or an electronic
pressure transducer.
The hydraulic system shall be capable to apply and to maintain a backpressure within ± 5 % on the specimen,
to facilitate saturation throughout the duration of the measurements.
The backpressure may be provided by a compressed gas supply, a dead-weight acting on a piston, or by any
other suitable means.
6.2 Flow measurement system
For the determination of flow volume within an accuracy of ± 5 %, a system shall be used with a graduated
accumulator, a graduated pipette, a vertical standpipe in conjunction with an electronic pressure transducer or
any other suitable device.
Both inflow and outflow volumes shall be measured unless the absence of leakage, the continuity of the flow
and the cessation of consolidation or swelling can be verified by other means.
6.3 Permeameter cell
An apparatus shall be used in which the specimen and porous end pieces, enclosed by a flexible membrane
sealed to the cap and base, are subjected to controlled fluid pressures.
The permeameter cell may allow for observation of changes in height of the specimen, either by observation
through the cell wall using a cathetometer or other instrument, or by monitoring of either a loading piston or an
extensometer extending through the top plate bearing on the top cap and connected to the dial indicator or
other measuring device. The piston or extensometer should pass through a bushing and seal incorporated
into the plate and shall be loaded with sufficient force to compensate for the cell pressure acting over the
cross-sectional area of the piston where it passes through the seal. If deformations are measured, the
deformation indicator shall be a dial indicator or cathetometer graduated to 0,3 mm or better and having an
adequate travel range, or any other suitable measuring device of the same accuracy.
6.4 Impermeable rigid top cap and base
This is intended to support the specimen, to provide for transmission of the permeant liquid and to form the
specimen.
The diameter or width of the top cap and the base shall be equal to the diameter of the specimen within ± 5 %.
The base shall prevent leakage, lateral motion or tilting and the top cap shall be designed to receive the piston
or extensometer if used, so that the contact area is concentric with the cap. The surface of base and top cap
in contact with the sealing membrane shall be smooth and free of scratches.
6.5 Flexible membrane
This membrane is intended to encase the specimen and to provide a reliable protection against leakage.
The membrane shall be carefully inspected prior to use and shall be discarded if any flaws or pinholes are
present. To minimize restrain of the specimen, the diameter shall be between 90 % and 95 % of that of the
specimen. The membrane shall be sealed to the specimen base and cap with rubber O-rings for which the
unstressed internal diameter or width is less than 90 % of the diameter or width of the base and cap.
6.6 Porous end pieces
These end pieces shall be made of silicon carbide, aluminium oxide or other material that is not attacked by
the specimen or the permeating liquid, with a diameter of (99 ± 1) mm and a thickness sufficient to prevent
breaking.
The end pieces shall have plane and smooth surfaces and be free of cracks, chips, and non-uniformities.
They shall be checked regularly to ensure that they are not clogged.
The hydraulic conductivity of the porous end pieces shall be substantially greater than that of the specimen to
be tested to avoid significant flow impedance.
6.7 Filter paper
This filter paper shall be used to prevent intrusion of
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