1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN 772-18:2011Methods of test for masonryunitsPart 18: Determination of freeze-thawresistance of calcium silicate masonry unitsBS EN 772-18:2011 BRITISH STANDARDNational forew
2、ordThis British Standard is the UK implementation of EN 772-18:2011. Itsupersedes BS EN 772-18:2000 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee B/519/1, Masonry units.A list of organizations represented on this committee can beobtained on request to
3、 its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. BSI 2011ISBN 978 0 580 70260 0ICS 91.080.30; 91.100.25Compliance with a British Standard cannot confer immunity fromlegal obligations.This British
4、Standard was published under the authority of theStandards Policy and Strategy Committee on 31 May 2011.Amendments issued since publicationDate Text affectedBS EN 772-18:2011EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 772-18 May 2011 ICS 91.100.25 Supersedes EN 772-18:2000English Version Me
5、thods of test for masonry units - Part 18: Determination of freeze-thaw resistance of calcium silicate masonry units Mthodes dessai des lments de maonnerie - Partie 18: Dtermination de la rsistance au gel/dgel des lments de maonnerie en silico-calcaire Prfverfahren fr Mauersteine - Teil 18: Bestimmu
6、ng des Frostwiderstandes von Kalksandsteinen This European Standard was approved by CEN on 25 December 2010. 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 altera
7、tion. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made
8、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
9、, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPIS
10、CHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2011 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 772-18:2011: EBS EN 772-18:2011EN 772-18:2011 (E) 2 Contents Page Foreword 31 Scope 42 Normative refe
11、rences 43 Principle 44 Symbols 45 Apparatus .46 Sampling 46.1 Sampling 46.2 Specimens for freeze-thaw testing .46.3 Specimens for compressive strength testing.57 Procedure 58 Evaluation of results 59 Test report .6Annex A (informative) Significant technical changes between this European standard and
12、 the previous edition .7BS EN 772-18:2011EN 772-18:2011 (E) 3 Foreword This document (EN 772-18:2011) has been prepared by Technical Committee CEN/TC 125 “Masonry”, the secretariat of which is held by BSI. This European Standard shall be given the status of a national standard, either by publication
13、 of an identical text or by endorsement, at the latest by November 2011, and conflicting national standards shall be withdrawn at the latest by November 2011. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shal
14、l not be held responsible for identifying any or all such patent rights. This document supersedes EN 772-18:2000. Annex A provides details of significant technical changes between this European Standard and the previous edition. According to the CEN/CENELEC Internal Regulations, the national standar
15、ds organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Pol
16、and, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN 772-18:2011EN 772-18:2011 (E) 4 1 Scope This European Standard specifies a method of determining the freeze-thaw resistance of calcium silicate masonry units. 2 Normative references The following ref
17、erenced 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 771-2:2003, Specification for masonry units Part 2: Calcium sil
18、icate masonry units EN 772-1, Methods of test for masonry units Part 1: Determination of compressive strength 3 Principle Calcium silicate masonry units are conditioned by immersion in water in a prescribed way and are then subjected to repeated cycles of freezing and thawing. Damage is assessed vis
19、ually. For samples where visual damage is apparent the compressive strength of the units can be compared with similar samples that have not been subjected to the freeze-thaw regime. 4 Symbols Rc is the reduction in strength (%); fn is the compressive strength of the sample that is set aside, (N/mm2)
20、; ff is the compressive strength of the sample that is subjected to the freeze-thaw cycling, (N/mm2); N is the total number of freeze-thaw cycles. 5 Apparatus Freezing cabinet, of net effective volume at least five times that of the volume of the samples to be tested and which is capable of developi
21、ng an even air temperature of -15 C in between 3 h and 5 h. 6 Sampling 6.1 Sampling The method of sampling shall be stated in the test report. The minimum number of specimens shall be as given in 6.2 below, but a larger minimum number may be specified in the product specification, in which case that
22、 larger number shall be used. 6.2 Specimens for freeze-thaw testing For units with a length 500 mm and/or height 300 mm, a total of three units is required from which representative portions may be cut in accordance with B.3 of EN 771-2:2003. BS EN 772-18:2011EN 772-18:2011 (E) 5 For units with a le
23、ngth 500 mm and a height 300 mm, the test shall be carried out on at least six whole units or on six specimens each of which is obtained by cutting in accordance with B.3 of EN 771-2:2003. 6.3 Specimens for compressive strength testing Sufficient specimens of either type, in accordance with EN 772-1
24、, shall be set aside and stored for compressive strength testing. 7 Procedure Mark any damage that may have been sustained by the specimens prior to the test. Immerse the specimens in water at 20 C 5 C oriented so that the longest dimension of each is in the vertical plane. Initially immerse to abou
25、t one quarter of their height and in such a way that water can circulate freely on all sides. After 1 h, immerse the specimens to about half the height of the specimens and after a further 1 h to three-quarters of their height. After 24 h, immerse the specimens fully in water. After a further 24 h r
26、emove them from the water or drain the water and then commence the freezing cycle with the specimens in the same position. Regulate the air temperature in the freezing cabinet so that it drops gradually in 3 h to 5 h to -15 C. Maintain this temperature for at least 2 h. After the freezing cycle, tha
27、w the specimens by immersing them fully in water at a temperature of 20 C 5 C for at least 1 h. Subject the specimens to the number of freeze-thaw cycles corresponding to the freeze-thaw category specified by the manufacturer, as described above. Note any visible damage to the specimens under the fo
28、llowing categories: loss of flatness, e.g. bulging of the surface of the specimens; cavities in excess of 5 mm diameter; cracking of the specimen (e.g. surface cracking). Ignore all previously marked damage. Evaluation of damage due to freezing and thawing shall be done only on the sides of the spec
29、imens that were not created by cutting. If the specimens do not exhibit any damage in any of the above-mentioned categories the testing may be terminated. When damage is noted, determine the compressive strength of the specimens that have been subjected to the freeze-thaw cycles and of those which h
30、ave been set aside (see Clause 6) in accordance with EN 772-1. 8 Evaluation of results Report any visual damage following the freeze thaw cycling. Calculate the reduction in compressive strength caused by the freeze-thaw cycling of the specimens where some or all were damaged from the untreated spec
31、imens set aside (see 6.2) as follows: BS EN 772-18:2011EN 772-18:2011 (E) 6 (%)100nfncff-f=RIf the specimens do not exhibit any damage in any of the above mentioned categories and the testing is terminated Rcmay be taken as Rc 20 % (by proxy visual assessment of damages, without calculation) 9 Test
32、report The test report shall include: a) name, title and date of issue of this European Standard; b) name of the organization that carried out the sampling and the method used; c) date of testing; d) type, origin and designation of the masonry unit by reference to EN 771-2 including whether facing o
33、r non-facing; e) number of specimens in the sample; f) date of delivery of the specimens to the testing laboratory; g) date of preparation of the specimens and the date of test; h) the total number of freeze thaw cycles to which the specimens were subjected; i) a description of any visual damage, af
34、ter freeze-thaw cycling, in accordance with Clause 7 or a statement that no damage has occurred; j) mean compressive strength of the specimens that have been subjected to freeze- thaw cycling, if necessary; k) mean compressive strength of the specimens that were set aside, if necessary; l) reduction
35、 in mean compressive strength, expressed as a percentage, to the nearest percent and whether the result was achieved by calculation or by proxy visual assessment of damages; m) remarks, if any. BS EN 772-18:2011EN 772-18:2011 (E) 7 Annex A (informative) Significant technical changes between this Eur
36、opean standard and the previous edition The number of freeze thaw cycles that the specimen is subjected to is determined by the category of freeze thaw resistance that is declared by the manufacturer in EN 771-2. Previously all specimens had been subjected to 50 cycles. In addition if no specimens a
37、re damaged as a result of the freeze thaw cycling the weight loss is taken to be less than 20 % without measurement. This page deliberately left blankThis page deliberately left blankBSI is the independent national body responsible for preparing British Standardsand other standards-related publicati
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