EN 680-2005 en Determination of the drying shrinkage of autoclaved aerated concrete《高压蒸养加气混凝土干燥收缩的测定》.pdf

1、BRITISH STANDARDBS EN 680:2005Determination of the drying shrinkage of autoclaved aerated concreteThe European Standard EN 680:2005 has the status of a British StandardICS 91.100.30g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g3

2、6g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN 680:2005This British Standard was published under the authority of the Standards Policy and Strategy Committee on 16 January 2006 BSI 16 January 2006ISBN 0 580 47515 8National forewordThis British Standard is the

3、official English language version of EN 680:2005. It supersedes BS EN 680:1994 which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee B/523, Prefabricated components of reinforced autoclaved aerated concrete and lightweight aggregate concrete with open struct

4、ure, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary.Cross-referencesThe British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under th

5、e section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct applicati

6、on. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests informed; monitor re

7、lated international and European developments and promulgate them in the UK.Summary of pagesThis document comprises a front cover, an inside front cover, the EN title page, pages 2 to 10, an inside back cover and a back cover.The BSI copyright notice displayed in this document indicates when the doc

8、ument was last issued.Amendments issued since publicationAmd. No. Date CommentsEUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 680December 2005ICS 91.100.30 Supersedes EN 680:1993 English VersionDetermination of the drying shrinkage of autoclaved aeratedconcreteDtermination du retrait de schage du

9、 bton cellulaireautoclavBestimmung des Schwindens von dampfgehrtetemPorenbetonThis European Standard was approved by CEN on 26 October 2005.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a nation

10、al standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Central Secretariat or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any ot

11、her language made by translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, Fra

12、nce,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManag

13、ement Centre: rue de Stassart, 36 B-1050 Brussels 2005 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 680:2005: EEN 680:2005 (E) 2 Contents Page Foreword 3 1 Scope .4 2 Normative references .4 3 Principle.4 4 Apparatus 4 5 Test spec

14、imens .5 5.1 Sample .5 5.2 Shape and size of the test specimens.5 5.3 Number of test specimens .5 5.4 Preparation of test specimens .6 5.5 Measurement of dimensions of test specimens and determination of their volume.6 5.6 Conditioning of test specimens.7 6 Testing procedure.7 6.1 Drying storage in

15、a climate at (20 2) C and (45 5) % relative humidity and determination of length changes and variations of mass7 6.2 Drying of test specimens at (105 5) C .7 7 Test results8 7.1 Calculation of relative length change8 7.2 Calculation of moisture content 8 7.3 Determination of the conventional referen

16、ce value of drying shrinkage .8 7.4 Determination of the total value of drying shrinkage.9 7.5 Calculation of the dry density9 8 Test report .9 EN 680:2005 (E) 3 Foreword This European Standard (EN 680:2005) has been prepared by Technical Committee CEN/TC 177 “Prefabricated reinforced components of

17、autoclaved aerated concrete or light-weight aggregate concrete with open structure”, the secretariat of which is held by DIN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by June 2006, and conflic

18、ting national standards shall be withdrawn at the latest by June 2006. This document supersedes EN 680:1993. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Cze

19、ch 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. EN 680:2005 (E) 4 1 Scope This Euopean Standard specifies

20、 a method for measuring the relative length changes due to drying (drying shrinkage) of autoclaved aerated concrete manufactured according to EN 771-4 or prEN 12602. The shrinkage characteristics determined according to this method are the following: The conventional reference value of drying shrink

21、age is the relative length change between two specified moisture contents. The total value of drying shrinkage is the relative length change due to drying from the saturated state until reaching constant length under specified climatic conditions. Other drying shrinkage values may be determined betw

22、een other parameters to meet other specified national requirements. 2 Normative references The following referenced documents are indispensable for the application of this European Standard. For dated references, only the edition cited applies. For undated references, the latest edition of the refer

23、enced document (including any amendments) applies. EN 678, Determination of dry density of autoclaved aerated concrete EN 771-4, Specification for masonry units Part 4:Autoclaved aerated concrete masonry units prEN 12602, Prefabricated reinforced components of autoclaved aerated concrete 3 Principle

24、 Prismatic test specimens are cut from products from new production. For conditioning they are saturated in water at (20 2) C for a period of at least 72 h and then stored in sealed plastic for a period of (24 2) h. Subsequently they are dried in air at (20 2) C and (45 5) % relative humidity (dryin

25、g period under reference shrinkage storage conditions) until constant length is reached. At the end of the conditioning period and in suitable time intervals during the drying period the length changes and the mass of the test specimens are determined. Finally, the test specimens are dried to consta

26、nt mass at (105 5) C in order to determine the dry density of the autoclaved aerated concrete and to enable the calculation of the moisture content of the test specimens at each measuring date from the difference between the mass in the actual moist state and the dry mass. A graph relative length ch

27、ange versus moisture content is plotted, and from the curve the conventional reference value of drying shrinkage, cs,ref, is determined as the relative length change between the two moisture contents 30 % by mass and 6 % by mass. Where the total value of drying shrinkage is required, the relative le

28、ngth change of the test specimens from the end of the conditioning period until reaching constant length under reference shrinkage storage conditions at (20 2) C and (45 5) % relative humidity shall also be measured. 4 Apparatus a) saw with rotating carborundum or diamond blade or other equipment fo

29、r cutting test specimens; b) balance, capable of determining the mass of the test specimens to an accuracy of 0,1 %; c) callipers, capable of reading the dimensions of the test specimens to an accuracy of 0,1 mm; d) container, for immersion of the test specimens under water; EN 680:2005 (E) 5 e) tem

30、perature and moisture controlled room or cabinet, capable of maintaining a temperature of (20 2) C and a relative humidity of (45 5) % for storing the test specimens during the drying period and for performing the measurement of length changes (see note); f) measuring apparatus (comparator) for meas

31、uring length changes of test specimens. Any suitable measuring apparatus may be used provided the following requirements are met: Length changes shall be measured in the longitudinal axis of the test specimens. Positive contact shall be established with the gauge plugs attached in the centres of the

32、 end faces of the test specimens. Measurements shall be performed with an accuracy of L/L 105, where L is the variation in gauge length and L is the initial length of the test specimens between the gauge plugs. Measuring apparatus shall have sufficient range to allow for variations in the actual len

33、gth of various test specimens. Means shall be provided for checking the measuring apparatus at each measuring date against an invariable reference. g) gauge plugs, to be applied on the end faces of the test specimens, made of corrosion-resistant metal and shaped in such a way that a reliable positiv

34、e contact with the measuring apparatus used is ensured. h) ventilated drying oven, capable of maintaining a temperature of (105 5) C. NOTE The room according to e) need not necessarily be humidity-controlled. Alternatively, during the drying period, the test specimens may be stored in a closed conta

35、iner under the specified climatic conditions. For the reference conditions the specified relative humidity of (45 5) % in the container can be obtained by means of saturated potash solution (KCO3). 5 Test specimens 5.1 Sample The sample for the preparation of the test specimens shall be taken in suc

36、h a manner that it is representative of the production to be investigated. In the case of prefabricated reinforced components the test specimens are prepared from the components themselves. Alternatively, they may be taken from prefabricated nonreinforced components of the same mould. 5.2 Shape and

37、size of the test specimens The test specimens shall be prisms with a cross-section of 40 mm 40 mm and a length to suit the length of the measuring apparatus, but not less than 160 mm. 5.3 Number of test specimens The test set, taken from either prefabricated reinforced components, from prefabricated

38、 nonreinforced components of the same mould or from nonreinforced masonry units, shall consist of three test specimens. Whenever possible, one test specimen shall be prepared from the upper third, one from the middle and one from the lower third of the component or of the masonry unit in the directi

39、on of rise of the mass during manufacture (see Figure 1). EN 680:2005 (E) 6 Key 1 Direction of rise Figure 1 Sampling scheme 5.4 Preparation of test specimens The test specimens shall be cut by means of a rotating carborundum blade or other equipment. They shall not contain any reinforcement. All su

40、rfaces shall be plane and clean. The longitudinal axis of the test specimens taken from a reinforced component or from an unreinforced component of the same mould shall be perpendicular to the direction of rise and preferably in the longitudinal direction of the reinforced component. The longitudina

41、l axis of the test specimens taken from unreinforced masonry units shall be perpendicular to the direction of rise and preferably in the vertical direction of the unit corresponding to the height of the unit. Test specimens may be prepared from samples which have previously been used for other tests

42、, provided that they are cut at least 150 mm from an area where visible damage or changes to the normal structure and appearance have occurred. Gauge plugs according to 4g) for measuring length changes shall be firmly attached to the centres of the end faces of the test specimens using an adhesive s

43、uch that the adhesive does not influence the result. NOTE For the determination of the moisture content of the autoclaved aerated concrete according to 7.2 it is necessary to know the mass of the gauge plugs and of their fixation (adhesive). 5.5 Measurement of dimensions of test specimens and determ

44、ination of their volume The initial dimensions of the test specimens shall be measured to an accuracy of 0,1 mm, using callipers. Width and thickness shall be measured between the longitudinal middle axes of opposite longitudinal surfaces near both ends and in the middle of the length. The length L

45、shall be measured along the longitudinal middle axes of two opposite longitudinal surfaces. The volume V of the test specimens shall be calculated by multiplying the mean values of thickness, width, and length measurements. EN 680:2005 (E) 7 5.6 Conditioning of test specimens After their preparation

46、, the test specimens shall be saturated with moisture by water storage for a period of at least 72 h at (20 2) C. For this purpose they shall be stored during the first 24 h with one third of their thickness, during the second 24 h with two thirds of their thickness and during the last 24 h totally

47、under water. Subsequently the test specimens shall be stored at this temperature in sealed plastic for 24 h to achieve even distribution of moisture. 6 Testing procedure 6.1 Drying storage in a climate at (20 2) C and (45 5) % relative humidity and determination of length changes and variations of m

48、ass In order to avoid faulty readings due to the presence of dirt, the gauge plugs shall be wiped carefully before each measurement. The first reading of the gauge length (Lc0) and of the invariable reference (Linv,0) and the first determination of the mass (m0) of the test specimens shall be made a

49、fter conditioning according to 5.6. Subsequently, the test specimens shall be gradually dried by storing in air at (20 2) C and a relative humidity of (45 5) %. During this period, they shall be placed on a grid with enough clear space around each other, enabling sufficient circulation of air around test specimens. To enable drawing of the graph shown in Figure 2 at least five readings of the gauge length, the length of the invariable reference and accompanying weighings of the test specimens shall