1、BRITISH STANDARD BSEN 1355:1997 Determination of creep strains under compression of autoclaved aerated concrete or lightweight aggregate concrete with open structure The European Standard EN1355:1996 has the status of a British Standard ICS91.100.30BSEN1355:1997 This British Standard, having been pr
2、epared under the directionof the Sector Board forBuilding and Civil Engineering, was published underthe authority oftheStandards Board and comes into effect on 15 October1997 BSI10-1999 The following BSI references relate to the work on this standard: Committee referenceB/523 Draft for comment93/110
3、407DC ISBN 0 580 27477 2 Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical CommitteeB/523, Prefabricated concrete and lightweight aggregate concrete with open structure, upon which the following bodies were represented: Aggregate Con
4、crete Block Association Autoclaved Aerated Concrete Association British Masonry Society British Precast Concrete Federation Ltd. Department of the Environment (Building Research Establishment) Institution of Structural Engineers Local Authority Organizations Amendments issued since publication Amd.
5、No. Date CommentsBSEN1355:1997 BSI 10-1999 i Contents Page Committees responsible Inside front cover National foreword ii Foreword 2 Text of EN1355 3 List of references Inside back coverBSEN1355:1997 ii BSI 10-1999 National foreword This British Standard has been prepared under the direction of Tech
6、nical CommitteeB/523 and is the English language version of EN1355:1996 Determination of creep strains under compression of autoclaved aerated concrete or lightweight aggregate concrete with open structure, published by the European Committee for Standardization (CEN). A British Standard does not pu
7、rport 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 British Standard
8、 EN678:1993 BSEN678:1994 Determination of the dry density of autoclaved aerated concrete EN679:1993 BSEN679:1994 Determination of compressive strength of autoclaved aerated concrete EN992:1995 BSEN992:1996 Determination of dry density of lightweight aggregate concrete with open structure EN1354:1996
9、 BSEN1354:1997 Determination of compressive strength of lightweight aggregate concrete with open structure Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, theEN title page, pages2 to8, an inside back cover and a back cover. This standard has been updated
10、(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 EN1355 December1996 ICS91.100.30 Descriptors: Concrete, cellular concrete, aggregates, mechanical tests, compressio
11、n tests, creep tests, determination, creep strength English version Determination of creep strains under compression of autoclaved aerated concrete or lightweight aggregate concrete with open structure Dtermination du fluage en compression du bton cellulaire autoclav et du bton de granulats lgers st
12、ructure ouverte Bestimmung der Kriechverformungen unter Druckbeanspruchung von dampfgehrtetem Porenbeton und von haufwerksporigem Leichtbeton This European Standard was approved by CEN on1996-11-30. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditi
13、ons 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 Secretariat or to any CEN member. The European Standards exist in three off
14、icial 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 official versions. CEN members are the national standards bodies of Austria,
15、 Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and UnitedKingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de
16、Stassart 36, B-1050 Brussels 1996 Copyright reserved to CEN members Ref.No.EN1355:1996EEN1355:1996 BSI 10-1999 2 Foreword This European Standard has been prepared by Technical CommitteeCEN/TC177, Prefabricated reinforced components of autoclaved aerated concrete or lightweight aggregate concrete wit
17、h 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 June1997, and conflicting national standards shall be withdrawn at the latest by June1997
18、. In order to meet the performance requirements as laid down in the product standards for prefabricated components of autoclaved aerated concrete and of lightweight aggregate concrete with open structure, a number of standardized test methods are necessary. According to the CEN/CENELEC Internal Regu
19、lations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom C
20、ontents Page Foreword 2 1 Scope 3 2 Normative references 3 3 Principle 3 4 Apparatus 3 5 Test specimens 4 5.1 Sample 4 5.2 Shape and size of test specimens 4 5.3 Number of test specimens 4 5.4 Preparation of test specimens 4 5.5 Measurement of test specimens 5 5.6 Conditioning of test specimens 5 6
21、Creep test 5 6.1 Age at loading and duration of sustained load 5 6.2 Loading details 5 7 Investigations after the creep test 6 8 Test results 6 9 Test report 7 Figure 1 Sampling scheme 4EN1355:1996 BSI 10-1999 3 1 Scope This European Standard specifies a method of determining the longitudinal long-t
22、erm strains (creep strains) of test specimens taken from prefabricated components of autoclaved aerated concrete (AAC) 1)or lightweight aggregate concrete with open structure (LAC) according to prEN1520 due to a constant compression stress sustained over a long period of time. 2 Normative references
23、 This European Standard incorporates by dated or undated reference, 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 p
24、ublications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. EN678, Determination of dry density of autoclaved aerated concrete. EN679, Determination of compressive strength of aut
25、oclaved aerated concrete. EN992, Determination of dry density of lightweight aggregate concrete with open structure. EN1354, Determination of compressive strength of lightweight aggregate concrete with open structure. prEN1520, Prefabricated components of lightweight aggregate concrete with open str
26、ucture. 3 Principle Creep strains are determined on test specimens taken from prefabricated components. The creep strain at a given aget ( cc,t ) is defined as the total strain under compression at that age ( cc,tot,t ), less the instantaneous strain under the same stress occurring during the applic
27、ation of the load ( ci,t0 ), less the strains due to shrinkage from the time of loading to the considered age( cs,t ). The strains due to shrinkage are determined on unloaded control specimens identical to those used in the creep test which are taken from the same component and stored under the same
28、 conditions. 4 Apparatus a) Any saw, suitable for cutting reinforced AAC or LAC components; b) Callipers, capable of reading the dimensions of the test specimens to an accuracy of0,1mm; c) A straight-edge, feeler gauges(0,1mm for AAC,0,5mm for LAC, and1,0mm for both) and a square; d) A balance, capa
29、ble of determining the mass of the test specimens to an accuracy of0,1%; e) Equalizing layers of soft fibreboard (only in the case of LAC), with a thickness of(12 2)mm and a density of(250 to400)kg/m 3to be inserted between the loadbearing surfaces of the test specimens and the platens of the compre
30、ssion testing machine (not required in the case of levelling the loadbearing surfaces by grinding or capping); f) A loading frame, capable of applying and maintaining the required compressive load on the test specimen(s) for the required period of time (in general at least one year), despite any len
31、gth change of the test specimen(s) (seenote1). The header plates of the loading frame shall have sufficient stiffness, and their bearing surface shall not depart from a plane by more than0,1mm per100mm. In any loading frame several test specimens may be stacked for simultaneous loading. Means shall
32、be provided for measuring the load to the nearest3% of the total applied load. This may be a permanently installed pressure gauge or a hydraulic jack or load cell inserted temporarily in the frame when the load is applied or adjusted. When a hydraulic load-maintaining element is used, several frames
33、 may be loaded simultaneously through a central hydraulic pressure-regulating unit. When springs are used, care shall be taken to provide a spherical seated head, or a ball joint and end plates rigid enough to ensure uniform loading of the test specimens. g) A measuring device, for the determination
34、 of the longitudinal length changes (strains) of the test specimens. The apparatus may be portable or attached (seenote2). If portable apparatus is used, gauge points shall be attached to the test specimen in a positive manner which is normally done by glueing with rapid hardening glue. The gauge le
35、ngth shall be not less than100mm. The gauge points shall be provided accurately on the longitudinal axes of the four longitudinal surfaces of the prismatic test specimens, and they shall be attached equidistant from the ends, the distance from the adjacent end being not lessthan50mm. 1) A European S
36、tandard for prefabricated reinforced components of autoclaved aerated concrete is in preparation at CEN.EN1355:1996 4 BSI 10-1999 The device shall be capable of measuring strains to the nearest10 10 6 (0,01mm/m) for at least one year without change in calibration. h) a room, capable of maintaining a
37、 temperature of(20 2) C and a relative humidity of(60 5)%; i) a ventilated drying oven, capable of maintaining a temperature of(105 5) C (seenote3). NOTE 1A usual frame consists of header plates bearing on the ends of the loaded test specimens, a load maintaining element that may be either a spring
38、or a hydraulic capsule or ram, connected with a cylinder of high pressure nitrogen and a hydraulic pressure-regulating unit, and threaded rods to take the reactions of the loaded system. NOTE 2Systems in which the varying length changes or strains are compared with a constant-length standard bar are
39、 considered most reliable. NOTE 3In addition, a ventilated drying oven capable of maintaining a temperature of(40 to60) C can be helpful for conditioning of test specimens. 5 Test specimens 5.1 Sample The sample for the preparation of the test specimens (usually at least one prefabricated component)
40、 shall be taken in such a manner that it is representative of the product to be investigated. 5.2 Shape and size of test specimens The reference test specimens shall be prisms with a square cross-section of100mm 100mm and a height of300mm. Test specimens of other sizes or shape may be used, provided
41、 that the correlation to the results of tests on the above reference test specimens is established. 5.3 Number of test specimens At least two test specimens for determination of creep (creep specimens) and two control specimens for determination of shrinkage shall be prepared from the central part o
42、f the component (seeFigure 1). 5.4 Preparation of test specimens The specimens shall be cut not less than2d after autoclaving or casting, respectively. The dust or the slurry of the process shall be removed. They shall be taken in such a way that their longitudinal axis is: The specimens shall conta
43、in no reinforcing bars within the gauge length. (If unavoidable, bars which are perpendicular to the longitudinal axis may be accepted in exceptional cases. This shall be mentioned in the test report.) The loadbearing surfaces of the creep specimens shall be plane, parallel to each other and perpend
44、icular to the longitudinal surfaces of the specimens. Planeness of loadbearing surfaces shall be checked across the two diagonals using a straight-edge and, if necessary, a feeler gauge. Deviations exceeding0,2mm shall be adjusted by cutting and/or grinding or by capping. In the case of LAC, deviati
45、ons up to0,5mm may be tolerated, provided that equalizing layers of soft fibreboard according to4 e) are used. Deviations from planeness of the other surfaces shall not exceed1mm. in the case of AAC: perpendicular to the rise of the mass during the manufacture; in the case of LAC: in the plane of th
46、e compression force acting in the component when used in the structure. Figure 1 Sampling schemeEN1355:1996 BSI 10-1999 5 The angle between the loadbearing surfaces and the adjacent longitudinal surfaces of the creep specimens shall not deviate from a right angle by more than1mm per100mm. This shall
47、 be checked along both orthogonal middle axes of the loadbearing surfaces by means of a square and a1mm-feeler gauge or similar instrument. Larger deviations shall be corrected by cutting or grinding. 5.5 Measurement of test specimens The dimensions of the creep specimens and control specimens shall
48、 be measured to an accuracy of0,1mm, using callipers. Length and width of the cross-sectional area, A c , shall be measured at mid height at two opposite longitudinal sides. The cross-sectional area shall be calculated using the mean values of the results of the measurements. The height of the speci
49、mens shall be measured in the middle of two opposite longitudinal sides. The volume V of the specimen shall be calculated by multiplying A cby the mean value of the results of the height measurements. 5.6 Conditioning of specimens The test specimens shall be conditioned at a temperature not exceeding60 C until their mass related moisture content is(6 2)%. This may be estimated by comparing their moist density with the dry density determined in accordance with EN678 for AAC or with EN992 for LAC, respectively, on companion specimens extracte
