BS EN 12350-7-2009 Testing fresh concrete nPart 7 Air content — Pressure nmethods《新拌混凝土试验 第7部分 空气含量 压力法》.pdf

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1、BS EN12350-7:2009ICS 91.100.30NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDTesting fresh concretePart 7: Air content PressuremethodsThis British Standardwas published under theauthority of the StandardsPolicy and StrategyCommittee on 31 May 2009 BSI 2009ISBN

2、978 0 580 58794 8Amendments/corrigenda issued since publicationDate CommentsBS EN 12350-7:2009National forewordThis British Standard is the UK implementation of EN 12350-7:2009. Itsupersedes BS EN 12350-7:2000 and which is withdrawn.The UK participation in its preparation was entrusted to TechnicalC

3、ommittee B/517/1, Concrete production and testing.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are responsible for its correct application.Compliance with

4、 a British Standard cannot confer immunityfrom legal obligations.BS EN 12350-7:2009EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 12350-7April 2009ICS 91.100.30 Supersedes EN 12350-7:2000 English VersionTesting fresh concrete - Part 7: Air content - Pressure methodsEssais pour bton frais - Partie

5、 7 : Teneur en air - Mthodede la compressibilitPrfung von Frischbeton - Teil 7: Luftgehalte -DruckverfahrenThis European Standard was approved by CEN on 20 January 2009.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanSt

6、andard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN Management Centre or to any CEN member.This European Standard exists in three official versions (English, Frenc

7、h, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Cze

8、ch Republic, Denmark, Estonia, 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 STANDARDIZATIONCOMIT EUROPEN

9、 DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: Avenue Marnix 17, B-1000 Brussels 2009 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 12350-7:2009: EBS EN 12350-7:2009EN 12350-7:2009 (E) 2 Contents Page Foreword 3

10、1 Scope 5 2 Normative references 5 3 Principles 5 4 Water column method .5 5 Pressure gauge method 9 6 Calculation and expression of results 13 7 Test report . 14 8 Precision 14 Annex A (Normative) Aggregate correction factor water column method 16 Annex B (Normative) Aggregate correction factor pre

11、ssure gauge method 18 Annex C (Normative) Calibration of apparatus water column method 20 Annex D (Normative) Calibration of apparatus pressure gauge method . 23 BS EN 12350-7:2009EN 12350-7:2009 (E) 3 Foreword This document (EN 12350-7:2009) has been prepared by Technical Committee CEN/TC 104 “Conc

12、rete and related products”, 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 October 2009, and conflicting national standards shall be withdrawn at the late

13、st by October 2009. 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 shall not be held responsible for identifying any or all such patent rights. This document supersedes EN 12350-7:2000. The results of a laborat

14、ory inter-comparison, in part funded by the EC under Measurement and Testing Programme, Contract MAT1-CT-94-0043 which investigated these two methods of measuring air content, did not find significant difference between them. However, it was found in this programme that the use of an internal vibrat

15、or to compact specimens of air entrained fresh concrete should only be done with caution, if loss of entrained air is to be avoided. The determination of the aggregate correction value for the two methods has been included in normative Annexes A and B. The method of calibrating the two types of appa

16、ratus has been included in normative Annexes C and D. This standard is one of a series concerned with testing fresh concrete. This series EN 12350 includes the following parts. EN 12350 Testing fresh concrete Part 1: Sampling; Part 2: Slump-test; Part 3: Vebe test; Part 4: Degree of compactability;

17、Part 5: Flow table test; Part 6: Density; Part 7: Air content Pressure methods; Part 8: Self-compacting concrete - Slump-flow test (in preparation); Part 9: Self-compacting concrete - V-funnel test (in preparation); Part 10: Self-compacting concrete - L-box test (in preparation); Part 11: Self-compa

18、cting concrete - Sieve segregation test (in preparation); Part 12: Self-compacting concrete - J-ring test (in preparation). BS EN 12350-7:2009EN 12350-7:2009 (E) 4 CAUTION When cement is mixed with water, alkali is released. Take precautions to avoid dry cement entering the eyes, mouth and nose whil

19、st mixing concrete. Prevent skin contact with wet cement or concrete by wearing suitable protective clothing. If cement or concrete enters the eye, immediately wash it out thoroughly with clean water and seek medical treatment without delay. Wash wet concrete off the skin immediately The following a

20、mendments have been made to the 2000-04 edition of this standard: editorial revision detailing and clarification of filling and compacting procedures of concrete in the container According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bo

21、und to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden,

22、Switzerland and the United Kingdom. BS EN 12350-7:2009EN 12350-7:2009 (E) 5 1 Scope This European Standard describes two methods for determination of air content of compacted fresh concrete, made with normal weight or relatively dense aggregate of maximum size up to 63 mm. NOTE Neither method is app

23、licable to concretes made with lightweight aggregates, air cooled blast-furnace slag, or aggregates with high porosity, because of the magnitude of the aggregate correction factor, compared with the entrained air content of the concrete. 2 Normative references The following referenced documents are

24、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 12350-1, Testing fresh concrete Part 1: Sampling EN 12350-6, Testing fresh concrete P

25、art 6: Density 3 Principles 3.1 General There are two test methods, both of which use apparatus which employ the principle of Boyle-Mariottes law. For the purpose of reference, the two methods are referred to as the water column method and the pressure gauge method and the apparatus as a water colum

26、n meter and a pressure gauge meter. 3.2 Water column method Water is introduced to a predetermined height above a sample of compacted concrete of known volume in a sealed container and a predetermined air pressure is applied over the water. The reduction in volume of the air in the concrete sample i

27、s measured by observing the amount by which the water level is lowered, the water column being calibrated in terms of percentage of air in the concrete sample. 3.3 Pressure gauge method A known volume of air at a known pressure is merged in a sealed container with the unknown volume of air in the co

28、ncrete sample. The dial on the pressure gauge is calibrated in terms of percentage of air for the resulting pressure. 4 Water column method 4.1 Apparatus 4.1.1 Water column meter, (see Figure 1), consisting of: a) Container, a cylindrical vessel of steel or other hard metal, not readily attacked by

29、cement paste, having a nominal capacity of at least 5 l and a ratio of diameter to height of not less than 0,75 nor more than 1,25. The outer rim and upper surface of the flange and the interior surfaces of the vessel shall be machined to a smooth finish. The container shall be watertight and in add

30、ition it, and the cover assembly, BS EN 12350-7:2009EN 12350-7:2009 (E) 6 shall be suitable for an operating pressure of approximately 0,1 MPa (N/mm2) and be sufficiently rigid to limit the pressure expansion constant, e (see A.8), to not more than 0,1 % air content; b) Cover assembly, a flanged rig

31、id conical cover fitted with a standpipe. The cover shall be of steel or other hard metal not readily attacked by cement paste and shall have interior surfaces inclined at not less than 10 from the surface of the flange. The outer rim and lower surface of the flange and the sloping interior face sha

32、ll be machined to a smooth finish. The cover shall have provision for being clamped to the container to make a pressure seal without entrapping air at the joint between the flanges of the cover and the container; c) Standpipe, consisting of a graduated glass tube of uniform bore, or a metal tube of

33、uniform bore with a glass gauge attached. The graduated scale shall indicate air content of 0 % to at least 8 % and preferably 10 %. The scale shall be graduated with divisions every 0,1 %, the divisions being not less than 2 mm apart. A scale in which 25 mm represents 1 % of air content is convenie

34、nt; d) Cover, fitted with a suitable device for venting the air chamber, a non-return air inlet valve and a small valve for bleeding off water. The applied pressure shall be indicated by a pressure gauge connected to the air chamber above the water column. The gauge shall be graduated with divisions

35、 every 0,005 MPa (N/mm2), the divisions being not less than 2 mm apart. The gauge shall have a full scale reading of 0,2 MPa (N/mm2); e) Deflecting plate or spray tube, of a thin non-corrodible disc of not less than 100 mm diameter to minimize disturbance of the concrete when water is added to the a

36、pparatus. Alternatively a brass spray tube of appropriate diameter which may be an integral part of the cover assembly or provided separately. The spray tube shall be constructed so that when water is added to the container it is sprayed onto the walls of the cover in such a manner as to flow down t

37、he sides causing minimum disturbance to the concrete; f) Airpump, with a lead facilitating connection to the non return air inlet valve on the cover assembly. The meter shall be in calibration at the time of the test, using the procedure in Annex C. If the meter has been moved to a location which di

38、ffers in elevation by more than 200 m from the location at which it was last calibrated, it shall be recalibrated. BS EN 12350-7:2009EN 12350-7:2009 (E) 7 a) Zero pressure b) System operating at pressure P c) Zero pressure release of pressure P Key: 1 Non-return valve 2 Air vent or valve 3 Bleed val

39、ve 4 Mark 5 Water 6 Clamp 7 Concrete 8 Air pump 9 Pressure lowered level h1 (reading at pressure P) h2 (reading at zero pressure after release of pressure P) Figure 1 Water column method apparatus NOTE h1 h2 = A1 when the container holds concrete as shown in Figure 1 h1 h2 = G (aggregate correction

40、factor) when the container holds only aggregate and water A1 G = Ac (air content of concrete) 4.1.2 Means of compacting the concrete, which may be one of the following: a) Internal (poker) vibrator, with a minimum frequency of approximately 120 Hz (7 200 cycles per exceeding approximately one-quarte

41、r of the smallest dimension of the test specimen); b) Vibrating table, with a minimum frequency of approximately 40 Hz (2 400 cycles per minute); c) Compacting rod, of circular cross-section, straight, made of steel, having a diameter of approximately 16 mm, length of approximately 600 mm and with r

42、ounded ends; d) Compacting bar, straight, made of steel having a square cross-section of approximately 25 mm 25 mm and length of approximately 380 mm. BS EN 12350-7:2009EN 12350-7:2009 (E) 8 4.1.3 Scoop, approximately 100 mm width 4.1.4 Steel trowel or float 4.1.5 Remixing container, flat tray of ri

43、gid construction and made from a non-absorbent material not readily attacked by cement paste. It shall be of appropriate dimensions such that the concrete can be thoroughly re-mixed, using the square-mouthed shovel 4.1.6 Shovel, with square mouth NOTE The square mouth is required to ensure proper mi

44、xing of material on the remixing container 4.1.7 Filling frame (optional), filling may be simplified by using a filling frame fitted tightly to the container; 4.1.8 Container with spout, having a capacity of 2 l to 5 l to fill the apparatus with water; 4.1.9 Mallet, soft-faced. 4.2 Procedure 4.2.1 S

45、ampling Obtain the sample of fresh concrete in accordance with EN 12350-1. Remix the sample before carrying out the test 4.2.2 Filling the container and compacting the concrete Using the scoop, place the concrete in the container in such a way as to remove as much entrapped air as possible. Dependin

46、g on the consistence of the concrete and the method of compaction, the container shall be filled in one or more layers to achieve full compaction by using one of the methods described in 4.2.3 or 4.2.4. Typically, concrete having a consistence equivalent to slump class S3 or greater will only requir

47、e one layer. In the case of self-compacting concrete, the container shall be filled in one operation and no mechanical compaction shall be applied during filling or after the container is filled. NOTE 1 Full compaction is achieved using mechanical vibration, when there is no further appearance of la

48、rge air bubbles on the surface of the concrete and the surface becomes relatively smooth with a glazed appearance, without excessive segregation. NOTE 2 The number of strokes per layer required to produce full compaction by hand will depend upon the consistency of the concrete. NOTE 3 Further guidan

49、ce on methods of compaction for concretes having different consistencies or cast in different sizes of moulds may be given in national annex NA. NOTE 4 The quantity of material used in the final layer shall be sufficient to fill the container without having to remove excess material. A small quantity of additional concrete may be added if necessary and further compacted in order to fill the container, but the removal of excess material should be avoided. BS EN 12350-7:2009EN 12350-7:2009 (E) 9 4.2.3 Mechanical vibration 4.2.3.1 Compacting with