1、BSI Standards PublicationPD CEN/TS 14418:2014Geosynthetic Barriers Test method for thedetermination of the influenceof freezing-thawing cycleson the permeability of claygeosynthetic barriersPD CEN/TS 14418:2014 PUBLISHED DOCUMENTNational forewordThis Published Document is the UK implementation of CE
2、N/TS 14418:2014. It supersedes DD CEN/TS 14418:2005 which iswithdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee B/553, Geotextiles and geomembranes.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does
3、 not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2014. Published by BSI StandardsLimited 2014ISBN 978 0 580 85550 4ICS 59.080.70Compliance with a British Standard cannot confer immunity fromlegal ob
4、ligations.This Published Document was published under the authority of theStandards Policy and Strategy Committee on 31 October 2014.Amendments issued since publicationDate Text affectedPD CEN/TS 14418:2014TECHNICAL SPECIFICATION SPCIFICATION TECHNIQUE TECHNISCHE SPEZIFIKATION CEN/TS 14418 October 2
5、014 ICS 59.080.70 Supersedes CEN/TS 14418:2005English Version Geosynthetic Barriers - Test method for the determination of the influence of freezing-thawing cycles on the permeability of clay geosynthetic barriers Gosynthtiques bentonitiques - Mthode dessai pour la dtermination de linfluence de cycl
6、es gel/dgel sur la permabilit des gosynthtiques bentonitiques Geosynthetische Dichtungsbahnen - Prfverfahren zur Bestimmung des Einflusses von Frost-Tau-Zyklen auf die Wasserdurchlssigkeit von geosynthetischen Tondichtungsbahnen This Technical Specification (CEN/TS) was approved by CEN on 21 July 20
7、14 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 require
8、d 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 conver
9、sion of the CEN/TS into an EN is reached. 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, Luxe
10、mbourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Bruss
11、els 2014 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. CEN/TS 14418:2014 EPD CEN/TS 14418:2014CEN/TS 14418:2014 (E) 2 Contents Page Foreword 3 Introduction .4 1 Scope 5 2 Normative references 5 3 Terms and definitions .5 4 Principle
12、 5 5 Apparatus .5 6 Reagent .6 7 Procedure .6 7.1 Specimen preparation .6 7.2 Specimen hydration 6 7.3 Specimen freezing .7 7.4 Specimen thawing .7 7.5 Repetition .7 7.6 Preparation of specimen for flux testing .7 8 Calculation and expression of results .8 8.1 Recording of data 8 8.2 Calculation and
13、 expression of results .8 9 Test Report .8 PD CEN/TS 14418:2014CEN/TS 14418:2014 (E) 3 Foreword This document (CEN/TS 14418:2014) has been prepared by Technical Committee CEN/TC 189 “Geosynthetics”, the secretariat of which is held by NBN. Attention is drawn to the possibility that some of the eleme
14、nts of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes CEN/TS 14418:2005. According to the CEN-CENELEC Internal Regulations, the national standards organizations of the followi
15、ng countries are bound to announce this Technical Specification: 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
16、, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. PD CEN/TS 14418:2014CEN/TS 14418:2014 (E) 4 Introduction This Technical Specification defines a method for testing the influence of freezing-thawing cycles on the flux of clay geosynth
17、etic 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 flux of saturated clay geosynthetic barriers may increase in conseque
18、nce of repeated freezing-thawing cycles. The 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 standard to establish appropriate safety and health practices and to comply with any regulations
19、or legislation regardless of the wording in the technical specification. The flux determined using this test method is not considered to be representative of the in-service flux of GBR-Cs. This test determines the influence of freezing-thawing cycles in the absence of any other phenomena, for exampl
20、e cation exchange. PD CEN/TS 14418:2014CEN/TS 14418:2014 (E) 5 1 Scope This Technical Specification describes an index test to determine the influence ratio of freezing-thawing cycles on the flux through saturated clay geosynthetic barriers. This test method is applicable to GBR-C products with no a
21、dditional sealing layers attached. 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 refer
22、enced document (including any amendments) applies. EN 16416, Geosynthetic clay barriers Determination of water flux index Flexible wall permeameter method at constant head EN ISO 3696, Water for analytical laboratory use Specification and test methods (ISO 3696) EN ISO 10320, Geotextiles and geotext
23、ile-related products - Identification on site (ISO 10320) ISO 554, Standard atmospheres for conditioning and/or testing Specifications 3 Terms and definitions For the purposes of this document, the following term and definition applies. 3.1 influence ratio ratio of the flux of a specimen exposed to
24、freezing-thawing cycles to that of 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 unexpo
25、sed reference specimens. A specimen either square with an edge length not less than 200 mm or circular with a diameter not less than 200 mm to a tolerance of 0,5 % is hydrated under a pressure of (4 0,2) kPa for 48 h at constant room temperature. After hydration, the specimen is stored in the freeze
26、r under a pressure of (4 0,2) kPa at 5 C for 24 h. After the freezing period the specimen is allowed to thaw under a pressure of (4 0,2) kPa at room temperature for 24 h. Then the specimen is hydrated again for 24 h at room temperature. This freezing-thawing cycle is performed four times before cutt
27、ing the test specimen. Eventually the test specimen and the unexposed reference specimen are tested in accordance with EN 16416. 5 Apparatus The apparatus shall consist of the following: a template of known dimensions to a tolerance of 0,5 % either square with an edge length not less than 200 mm or
28、circular with a diameter not less than 200 mm, a waterproof box large enough to accommodate the specimen, PD CEN/TS 14418:2014CEN/TS 14418:2014 (E) 6 a rigid chemically inert pressure plate of the same dimensions as the specimen, and not less than 10 mm thick, sufficient weights to exert a pressure
29、of (4 0,2) kPa on the specimen (allowing for the weight of the pressure plate), a mechanically bonded nonwoven geotextile with a mass per unit area of (250 50) g/m2, a freezer capable to maintain a temperature of (5 2) C. 6 Reagent De-ionized water in accordance with EN ISO 3696, grade 3. 7 Procedur
30、e 7.1 Specimen preparation Inspect the bulk clay geosynthetic barrier specimen to be tested and record any disturbance, irregularity or damage. Choose two representative sections of the specimen for testing, one for the reference specimen and one for the test specimen to be submitted to the freezing
31、-thawing cycles. Place the template on the selected section. Cut the specimens to the exact size of the template with a sharp knife or any other suitable instrument. Remove the specimens carefully to avoid loss of bentonite. The specimen size may be limited by safety restrictions on the total mass o
32、f the weights where these are to be transported manually. Seal the edges of the clay geosynthetic barrier specimens with waterproof tape or self-adhesive aluminium foil to prevent bentonite loss during further handling. 7.2 Specimen hydration Fill a waterproof box with water. Place a piece of mechan
33、ically bonded nonwoven geotextile with a mass per unit area of (250 50) g/m2on the bottom of the box and manually remove any air bubbles. Place the GBR-C sample on the nonwoven and then put a further piece of similar nonwoven geotextile on top of the GBR-C and manually remove any air bubbles. Place
34、a pressure plate on the “sandwich” of specimens. Place weights on the pressure plate to obtain a required pressure of (4 0,2) kPa. PD CEN/TS 14418:2014CEN/TS 14418:2014 (E) 7 Key 1 dead load 2 pressure plate 3 GBR-C sample 4 mechanically bonded nonwoven geotextile 5 waterproof box Figure 1 GBR-C hyd
35、ration setup NOTE The use of drainage mats instead of nonwoven geotextile results in unevenness in the surface of GBR-Cs. This could lead to incorrect measurements. Add de-ionized water to the box so that the water level is not above the top of the pressure plate. In order to maintain the GBR-C spec
36、imen submerged, add water at the rate it is absorbed by the GBR-C specimen. Keep the specimen submerged at room temperature selected according to ISO 554 and at a pressure of (4 0,2) kPa. 7.3 Specimen freezing After 48 h, remove the excess water from the box. Preset the freezer to a temperature of (
37、5 2) C prior to placing specimen inside it. Move the box containing the test specimen with the weights and the pressure plate to the freezer. Allow the test specimen to freeze for 24 h. The freezer temperature shall be (5 2) C. 7.4 Specimen thawing After the freezing period allow the specimen to tha
38、w for 24 h at room temperature selected according to ISO 554 without adding any water. Then add water again according to the procedure described in 7.2. Submerge the specimen again for a minimum of 24 h at room temperature selected according to ISO 554 without adding any water unless it can be shown
39、 that omitting this point has no influence on the test result. 7.5 Repetition Repeat steps from 7.2 to 7.4 a further three times. 7.6 Preparation of specimen for flux testing Remove the weights and the nonwoven geotextile pieces and the clay geosynthetic barrier specimen from the box and carefully p
40、lace the specimen on a flat smooth surface. PD CEN/TS 14418:2014CEN/TS 14418:2014 (E) 8 Take a (100 2) mm diameter specimen and perform the test in accordance with EN 16416. Perform the test in accordance with EN 16416 on an unexposed reference specimen. 8 Calculation and expression of results 8.1 R
41、ecording of data The following data shall be recorded for each test: a) the duration of the different conditioning periods (saturation, freezing, thawing); b) the freezer temperature; c) all flux values determined and the corresponding time periods. 8.2 Calculation and expression of results Calculat
42、e the influence ratio R of freezing-thawing cycles as follows: 100testreference()qRq= where qtestis the flux value (in m3/(m2.s) of the test specimen after exposure to the wetting-drying cycles; qreferenceis the flux value in (m3/(m2.s) of the reference specimen. 9 Test Report The test report shall
43、include the following particulars: a) number and date of this standard; b) identification of the sample in accordance with EN ISO 10320, date of receipt and date of testing; c) conditioning atmosphere; d) the results obtained, expressed in accordance with 8.2. This page deliberately left blankBSI is
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