1、BRITISH STANDARDBS EN 14721:2005 +A1:2007Test method for metallic fibre concrete Measuring the fibre content in fresh and hardened concreteICS 91.100.30g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g4
2、0g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN 14721:2005+A1:2007This British Standard was published under the authority of the Standards Policy and Strategy Committee on 13 December 2005 BSI 2008ISBN 978 0 580 61100 1National forewordThis British Standard is the UK implementation of EN 1
3、4721:2005+A1:2007. It supersedes BS EN 14721:2005 which is withdrawn.The start and finish of text introduced or altered by amendment is indicated in the text by tags. Tags indicating changes to CEN text carry the number of the CEN amendment. For example, text altered by CEN amendment A1 is indicated
4、 by !“.The UK participation in its preparation was entrusted to Technical Committee B/524, Precast concrete products.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contra
5、ct. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.Amendments/corrigenda issued since publicationDate Comments31 January 2008 Implementation of CEN amendment A1:2007EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM E
6、N 14721:2005+A1 September 2007 ICS 91.100.30 Supersedes EN 14721:2005 English Version Test method for metallic fibre concrete - Measuring the fibre content in fresh and hardened concrete Mthode dessai du bton de fibres mtalliques - Mesurage de la teneur en fibres du bton frais ou durci Prfverfahren
7、fr Beton mit metallischen Fasern - Bestimmung des Fasergehalts in Frisch- und Festbeton This European Standard was approved by CEN on 27 June 2005 and includes Amendment 1 approved by CEN on 16 August 2007. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the
8、 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 CEN Management Centre or to any CEN member. This European Standard exists i
9、n 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 CEN Management Centre has the same status as the official versions. CEN members are the national standards bodie
10、s of 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, Switzerland and United Kingdom. EURO
11、PEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 2007 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 14721:2005+A1:2007: EBS EN
12、 14721:2005+A1:2007 (E) 2 Contents Page Foreword3 1 Scope 4 2 Normative references 4 3 Principle4 4 Apparatus .4 5 Test specimens5 6 Testing procedures5 7 Expression of results 7 8 Test report 7 9 Precision.7 BS EN 14721:2005+A1:2007 (E) 3 Foreword This European Standard (EN 14721:2005+A1:2007) has
13、been prepared by Technical Committee CEN/TC 229 “Precast concrete products”, the secretariat of which is held by AFNOR. This document shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by March 2008 and conflicting national s
14、tandards shall be withdrawn at the latest by March 2008. This document includes Amendment 1, approved by CEN on 2007-08-16. This document supersedes EN 14721:2005. The start and finish of text introduced or altered by amendment is indicated in the text by tags ! “. According to the CEN/CENELEC Inter
15、nal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Mal
16、ta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. BS EN 14721:2005+A1:2007 (E) 4 1 Scope This European Standard specifies two methods of measuring the fibre content of metallic fibre concrete. Method A measures the fibre content of
17、 a hardened concrete specimen. Method B measures the fibre content of a fresh concrete specimen. !This European Standard does not apply to sprayed concrete.“ 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only t
18、he edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 12350-6, Testing fresh concrete Part 6: Density EN 12390-7, Testing hardened concrete Part 7: Density of hardened concrete 3 Principle Fibres are extracted from a ha
19、rdened (Method A) or fresh (Method B) concrete sample and the fibre content is determined from the mass of fibre and the volume of the concrete sample. 4 Apparatus 4.1 Method A 4.1.1 Core drill equipment, capable of extracting test cores from the hardened concrete to the volume set out in 5.1. 4.1.2
20、 Callipers and/or rules, capable of measuring the dimensions of test cores to an accuracy of 0,5 mm. 4.1.3 Balance, equipped with a stirrup for weighing the test core in both air and water to an accuracy of 10 g. 4.1.4 Water tank, fitted with a device to maintain water at a constant level and of suf
21、ficient size to allow the test core on the stirrup to be fully immersed to a constant depth. 4.1.5 Balance or scales, capable of determining the mass of the extracted metallic fibres to an accuracy of 0,5 g. 4.2 Method B 4.2.1 Container, watertight, of sufficient rigidity to retain its shape, made o
22、f metal not readily attacked by cement paste, having a smooth internal face, with the rim machined to a plane surface. The rim and base shall be parallel. The smallest dimension of the container shall be at least four times the maximum nominal size of the coarse aggregate in the concrete, but shall
23、be not less than 150 mm. The volume of the container shall be not less than 3 . 4.2.2 Scoop, or similar sampling device, made from non-absorbent material not readily attacked by cement paste, suitable for taking increments of concrete. BS EN 14721:2005+A1:2007 (E) 5 4.2.3 Means of compacting the con
24、crete, which may be one of the following: internal (poker) vibrator with a minimum frequency of approximately 120 Hz, the diameter of the internal vibrator not exceeding approximately one-quarter of the smallest dimension of the container; vibrating table with a minimum frequency of approximately 40
25、 Hz. 4.2.4 Steel trowel or float. 4.2.5 Balance or scales, capable of determining the mass of the extracted metallic fibres to an accuracy of 0,5 g. 4.2.6 Sieve or filter equipment, suitable for washing out cement and other fine materials from fresh concrete. 5 Test specimens 5.1 Method A - Hardened
26、 specimen The hardened test specimen shall consist of 3 or more test cores obtained in accordance with 6.1.1. The volume of a test core shall be 1 or more. The volume of the test specimen shall be 5 or more. 5.2 Method B - Fresh specimen The fresh test specimen shall consist of 3 or more test sample
27、s obtained in accordance with 6.1.2. The volume of each test sample shall be 3 or more. 6 Testing procedures 6.1 Sampling 6.1.1 Method A 6.1.1.1 Drilling cores The cores shall be drilled perpendicular to the product surface. The drill shall be kept positioned rigidly during coring. 6.1.2 Method B 6.
28、1.2.1 Filling the container Clean all the apparatus to use. Using the scoop take the required number of increments from the discharging stream of concrete from the mixer, disregarding the very first part and the very last part. When sampling from a falling stream, take the increments in such a way a
29、s to represent the whole width and thickness of the stream. Deposit the increments into the container. 6.1.2.2 Compacting the concrete Immediately after placing in the container, the concrete shall be compacted, if necessary, in a manner comparable to that used in the application. BS EN 14721:2005+A
30、1:2007 (E) 6 6.2 Volume of sample 6.2.1 Method A - Hardened sample The volume of each test core shall be determined by calculation using measured values of actual dimensions or by water displacement in compliance with EN 12390-7. The volume V of the test core shall be expressed to the nearest 0,02 .
31、 6.2.2 Method B - Fresh sample The volume of the container shall be obtained by calibration in compliance with EN 12350-6. The volume of each test sample shall be determined by one of either following methods. In case the container is completely filled after compaction, the concrete shall be levelle
32、d off, using the steel trowel or float. Then the volume of the fresh sample is equal to the volume of the container. In case the container is not completely filled after compacting the concrete, the container shall be placed on a horizontal surface and the volume of water required to fill the contai
33、ner shall be measured. Then the volume of the fresh sample is equal to the volume of the container less the volume of the water added. The volume V of the test sample shall be expressed to the nearest 0,02 . 6.3 Mass of fibre 6.3.1 Method A - Hardened sample Each test core shall be crushed in a comp
34、ression testing machine, or other suitable device, so that all the fibres can be separated from the concrete. Magnetic fibres may be collected by using a magnet. The collected fibres shall be thoroughly cleaned and then weighed. The mass m of the fibres shall be expressed to the nearest 0,5 g. 6.3.2
35、 Method B - Fresh sample Each test sample shall be placed in a sieve or filter equipment where the cement and other fine materials can be washed out so that the fibres can be separated from the mass. Magnetic fibres may be collected directly or after washing out by using a magnet. The collected fibr
36、es shall be cleaned, dried and then weighed. The mass m of the fibres shall be expressed to the nearest 0,5 g. BS EN 14721:2005+A1:2007 (E) 7 7 Expression of results The fibre content shall be calculated from the determined fibre mass and sample volume, using the formula: VmC f=where Cfis the fibre
37、content, in kg/m3; m is the mass of fibre extracted from the sample, in g; V is the volume of the sample, in . 8 Test report The test report shall include: a) identification of the test specimen; b) description of the method (A or B) and in case of method B the placing and compacting procedure used;
38、 c) volume of each sample to the nearest 0,02 ; d) mass of the fibres in each sample to the nearest 0,5 g; e) the calculated fibre content of each sample to the nearest kg/m3; f) the average value of the fibre content to the nearest kg/m3; g) reference to this European Standard; h) any deviation fro
39、m the standard testing method; i) !place and date of testing, testing institute and person responsible for testing;“ j) a declaration from the person technically responsible for the test that the testing was carried out in accordance with this standard, except for the indicated deviation(s). The tes
40、t report may include the identification and/or description of the fibre type. 9 Precision Beside the following indicative data, no precision data in terms of repeatability or reproducibility are available. In case of method A a loss up to 5 % of the mass of fibres may occur in the process of crushin
41、g and collecting. In case of method B no fibre loss occurs. BS EN 14721:2005 +A1:2007BSI389 Chiswick High RoadLondonW4 4ALBSI British Standards InstitutionBSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Europe and at the inter
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