BS EN 989-1996 Determination of the bond behaviour between reinforcing bars and autoclaved aerated concrete by the push-out test《采用推挤试验法测定增强棒材和热压充气混凝土胶合力》.pdf

1、BRITISH STANDARD BS EN 989:1996 Determination of the bond behaviour between reinforcing bars and autoclaved aerated concrete by the “push-out” test The European Standard EN 989:1995 has the status of a British Standard ICS 91.080.40; 91.100.30BS EN989:1996 This British Standard, having been prepared

2、 under the directionof the Sector Board forBuilding and Civil Engineering, was published underthe authority of the Standards Board and comes into effect on 15 April 1996 BSI 11-1999 The following BSI references relate to the work on this standard: Committee reference B/523 Draft for comment 93/10097

3、6 DC ISBN 0 580 25350 3 Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee B/523, Prefabricated components of reinforced autoclaved aerated concrete and lightweight aggregate concrete with open structure, upon which the foll

4、owing bodies were represented: Aggregate Concrete Block Association Autoclaved Aerated Concrete Products Association British Masonry Society British Precast Concrete Federation Ltd. Department of the Environment (Building Research Establishment) Institution of Structural Engineers Local Authority Or

5、ganizations Amendments issued since publication Amd. No. Date CommentsBS EN989:1996 BSI 11-1999 i Contents Page Committees responsible Inside front cover National foreword ii Foreword 2 Text of EN 989 3 List of references Inside back coverBS EN989:1996 ii BSI 11-1999 National foreword This British S

6、tandard has been prepared by Technical Committee B/523 and is the English language version of EN989:1995 Determination of the bond behaviour between reinforcing bars and autoclaved aerated concrete by the “push-out” test, published by the European Committee for Standardization (CEN). A British Stand

7、ard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross-references Publication referred to Corresponding B

8、ritish Standard EN 678:1993 BS EN 678:1994 Determination of the dry density of autoclaved aerated concrete EN 679:1993 BS EN 679:1994 Determination of compressive strength of autoclaved aerated concrete Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, th

9、eEN title page, pages 2 to 8, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 989 May 1995

10、 ICS 91.080.40; 91.100.30 Descriptors: Concrete, cellular concrete, reinforced concrete, armatures, metal bars, tests, adhesion, procedure English version Determination of the bond behaviour between reinforcing bars and autoclaved aerated concrete by the “Push-Out” test Dtermination par un essai dad

11、hrence par pousse du comportement dadhrence entre lesarmatures et le bton cellulaire autoclav Bestimmung des Verbundverhaltens zwischen Bewehrungsstahl und dampfgehrtetem Porenbeton mit Hilfe der Ausdrckprfung This European Standard was approved by CEN on 1995-04-14. CEN members are bound to comply

12、with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secret

13、ariat or to any CEN member. This European Standard exists 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 Central Secretariat has the same status as the offici

14、al versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de No

15、rmalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1995 All rights of reproduction and communication in any form and by any means reserved in all countries to CEN and its members. Ref. No. EN 989:1995 EEN989:1995 BSI 11-1999 2 Foreword This European S

16、tandard was prepared by the Technical Committee CEN/TC 177, Prefabricated reinforced components of autoclaved aerated concrete or lightweight aggregate concrete with open structure, of which the secretariat is held by DIN. This European Standard shall be given the status of a national standard, eith

17、er by publication of an identical text or by endorsement, at the latest by November1995, and conflicting national standards shall be withdrawn at the latest by November1995. In order to meet the performance requirements as laid down in the product standard for prefabricated components of lightweight

18、 aggregate concrete with open structure a number of standardized test methods are necessary. According to the CEN/CENELEC Internal Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy,

19、 Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Contents Page Foreword 2 1 Scope 3 2 Normative references 3 3 Principle 3 4 Apparatus 3 5 Test specimens 3 5.1 Sampling 3 5.2 Shape and size of test specimens 3 5.3 Number of test specimens 3 5.4 Preparati

20、on of test specimens 3 5.5 Conditioning of test specimens 6 6 Procedure 6 7 Test results 6 8 Test report 7 Figure 1 Suggested arrangement for push-out test 4 Figure 2 Holder for transducer 5 Figure 3 Hemispherical metal piece 5EN989:1995 BSI 11-1999 3 1 Scope This European Standard specifies a metho

21、d of determining the bond behaviour between reinforcing bars and autoclaved aerated concrete (AAC) 1) . The test may be used for quality control purposes. Values to be used in design cannot be derived from the test results. 2 Normative references This European Standard incorporates by dated or undat

22、ed references, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when

23、incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. EN 678, Determination of the dry density of autoclaved aerated concrete. EN 679, Determination of the compressive strength of autoclaved aerated concrete. 3 Principle Test s

24、pecimens are taken from reinforced components by cutting them in transverse direction. A compressive force is applied onto the cut end of a reinforcing bar while the opposite surface of the test specimen is supported in such a way that pushing-out of the loaded bar is not hindered. The force is incr

25、eased at a prescribed steady rate until the bond fails and the bar is pushed out. The slip of the bar relative to the concrete is measured at the free end, and the load-slip curve is recorded. 4 Apparatus a) Saw, for cutting test specimens from reinforced AAC components without excessive heating, vi

26、bration or shock. b) Testing machine or loading device, capable of applying a compression force at the required steady rate without shock and with an accuracy of2% of the ultimate push-out force. c) Distance frame, to be inserted between the upper surface of the test specimen and the upper bearing b

27、lock of the testing machine. The frame consists of two sufficiently rigid steel platens which are connected by bolts long enough to provide sufficient space for the accommodation of the slip measuring device. d) Intermediate layer of soft fibre board, (thickness 10mm to20mm, density250kg/m 3to300kg/

28、m 3 , with four holes of20mm diameter) between the upper surface of the test specimen and the distance frame. e) Hemispherical metal piece,e.g.the head of a cup-headed bolt for centering and transmission of the load to the reinforcing bar. f) Device, for measuring the slip between the reinforcing ba

29、r and the AAC with an accuracy of 1/100mm and for recording the load-slip curve. g) Ventilated drying oven, maintainable at a temperature of (105 5) C. h) Balance, for weighing test specimens to an accuracy of0,1%. 5 Test specimens 5.1 Sampling The test specimens shall be taken from reinforced compo

30、nents in such a manner that they are representative of the products to be investigated. 5.2 Shape and size of test specimens The test specimens are prismatic sections taken from reinforced AAC components in such a way that the cross section of the test specimen corresponds to the section of the comp

31、onent. The length of the test specimens shall be200mm. The bond length to be tested shall be (180 5)mm. 5.3 Number of test specimens The number of test specimens shall be such that bond behaviour can be determined on at least five sections of longitudinal reinforcing bars. At least three different l

32、ongitudinal bars shall be tested. 5.4 Preparation of test specimens The test specimens are obtained by cutting the component in transverse direction with a saw as specified in4 a). Care shall be taken that there are no cross bars connected with the longitudinal bars to be tested. To avoid undue infl

33、uence of burrs, each end of the bars to be tested shall be separated from the surrounding AAC to a depth of about10mm,e.g.by means of a core drill of suitable diameter (seeFigure 1). 1) A standard about prefabricated reinforced components of autoclaved aerated concrete is in preparation.EN989:1995 4

34、 BSI 11-1999 Dimensions in millimetres 1 Distance frame 2 Displacement transducer 3 Holder for transducer (see Figure 2) 4 Soft fibre board 5 Recess 6 AAC test specimen 7 Reinforcing bar with diameter d 8 Concrete cover 9 Hemispherical metal piece (see Figure 3) 10 Temporary support (wedges) to loca

35、te test specimens to be removed after applying sufficient preload to hold the test specimens in upright position Figure 1 Suggested arrangement for push-out testEN989:1995 BSI 11-1999 5 Dimensions in millimetres Holder for transducer with three legs supported on the surface of AAC test specimen. Tra

36、nsducer and legs are exchangeable. If the transducer is mounted in positions 1 or 3 when bars near the edges are tested, a counterweight has to be applied at 3 or 1, respectively. Figure 2 Holder for transducer Dimensions in millimetres Figure 3 Hemispherical metal pieceEN989:1995 6 BSI 11-1999 5.5

37、Conditioning of test specimens The test specimens shall be stored in such a manner that, when tested, they have a temperature of(20 5) C (see note1) and a moisture content of(6 2)% by mass (see note2). If necessary, the test specimens shall be dried or moistened until their mass lies within the calc

38、ulated limits (see note2). Subsequently, they shall be stored prior to testing for at least3d in plastic bags or similar sealing to achieve a sufficiently uniform moisture distribution within the AAC. The actual moisture content shall be verified by determining the mass of the test specimens in the

39、humid state immediately before the test and after drying at (105 5) C until constant mass has been obtained. The error in determining the mass shall not exceed 0,1% of the mass of the test specimen. The mass of the test specimen is considered constant if after24h of further drying the mass has not c

40、hanged by more than0,2%. The moisture content m is calculated as follows: where NOTE 1Other temperatures may be chosen in special cases. This shall be indicated in the test report. NOTE 2In order to achieve the prescribed moisture content within the test specimens, the following procedure is recomme

41、nded. The required humid mass of the test specimen is calculated using the following equation: where 6 Procedure A suggested testing arrangement is shown inFigure 1. The hemispherical metal piece is fixed on top of the bar to be pushed out,e.g.by means of adhesive tape. Then the test specimen is pla

42、ced upside down on the lower bearing block of the testing machine or loading device, respectively, where it rests on the hemispherical metal piece and two or more auxiliary wedges which are used to hold the test specimen in position at the beginning of the test. The fibre board is placed on top of t

43、he test specimen with the hole for the feeler or the transducer over the bar to be tested. Then the distance frame for the accommodation of the slip measuring device is brought into position, the four holes in the bottom plate coinciding with the corresponding holes in the fibre board. The slip meas

44、uring device is applied, the three legs resting on the concrete surface and the feeler of the transducer being in contact with the end of the reinforcing bar. Then a certain preload is applied which is sufficiently high to press the test specimen and the distance frame firmly enough against the bear

45、ing blocks of the testing machine to hold them securely in an upright position. The auxiliary wedges are removed and the load is increased at an approximately steady rate calculated to achieve rupture after60s to 90s. During the loading procedure, the load-slip curve is recorded. 7 Test results The

46、bond strength f bis calculated as follows: where The bond strength f bof the individual bars tested and the mean value shall be expressed to the nearest0,1N/mm 2 . m is the moisture content, in per cent by mass; m h is the mass of the test specimen in the humid state, in kilograms; m d is the mass o

47、f the dried test specimen immediately after removal from the drying oven, in kilograms; m s is the mass of the steel reinforcement contained in the test specimen, in kilograms. m h,r is the required mass of the test specimen in the humid state, in kilograms; m d,ref is the dry mass of a reference sp

48、ecimen with the same dimensions and the same reinforcement taken from the same component, the dry mass, in kilograms, being determined according to the last paragraph of 5.5; m s is the mass of the reinforcement, determined either by weighing or by calculation from the dimensions of the reinforcing

49、bars and the density of steel (7850 kg/m 3 ), in kilograms; m is the prescribed moisture content, in per cent by mass (6 2)% by mass. f b is the bond strength, in newtons per square millimetre; F u is the maximum load carried by the bar, in newtons; L is the effective bond length (total length of the test specimen minus the depth of the recesses at the ends of the bar), in millimetres, determined to the nearest mm; d is the nominal diameter of the reinforcing bar (not including coating), in millimetres, determined to the