BS EN 932-2-1999 Tests for general properties of aggregates - Methods for reducing laboratory samples《集料的一般性能试验 减少试验室取样方法》.pdf

《BS EN 932-2-1999 Tests for general properties of aggregates - Methods for reducing laboratory samples《集料的一般性能试验 减少试验室取样方法》.pdf》由会员分享，可在线阅读，更多相关《BS EN 932-2-1999 Tests for general properties of aggregates - Methods for reducing laboratory samples《集料的一般性能试验 减少试验室取样方法》.pdf（14页珍藏版）》请在麦多课文档分享上搜索。

1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS EN 932-2:1999 The Euro

2、pean Standard EN 932-2:1998 has the status of a British Standard ICS 91.100.15 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Tests for general properties of aggregates Part 2: Methods for reducing laboratory samplesThis British Standard, having been prepared under the direct

3、ion of the Sector Committee for Building and Civil Engineering, was published under the authority of the Standards Committee and comes into effect on 15 May 1999 BSI 05-1999 ISBN 0 580 32099 5 BS EN 932-2:1999 Amendments issued since publication Amd. No. Date Text affected National foreword This Bri

4、tish Standard is the English language version of EN 932-2:1998. It is included in a package of European Standards agreed by CEN/TC 154. The UK participation in its preparation was entrusted by Technical Committee B/502, Aggregates, to Subcommittee B/502/6, Methods of test, which has the responsibili

5、ty to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. A list of

6、organizations represented on this subcommittee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International

7、 Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard 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

8、Standard does not of itself confer immunity from legal obligations. Summary of pages This 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.CEN European Committee for Standardization Comite Europe en de Normalisation Euro

9、pa isches Komitee fu r Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1999 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 932-2:1999 E EUROPEAN STANDARD EN 932-2 NORME EUROPE ENNE EUROPA ISCHE NORM January 1999 I

10、CS 91.100.15 Descriptors: aggregates, tests, samples, specimen preparation, reduction methods English version Tests for general properties of aggregates Part 2: Methods for reducing laboratory samples Essais pour de terminer les proprie te sg e ne rales des granulats Partie 2: Me thodes de re ductio

11、n dun e chantillon de laboratoire Pru fverfahren fu r allgemeine Eigenschaften von Gesteinsko rnungen Teil 2: Verfahren zum Einengen zum Laboratoriumsproben This European Standard was approved by CEN on 26 December 1998. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which

12、 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 Secretariat or to any CEN member. This European Stand

13、ard 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 official versions. CEN members are the national stand

14、ards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.Page 2 EN 932-2:1999 BSI 05-1999 Foreword This European Standard has been prepared by Technica

15、l Committee CEN/TC 154, Aggregates, the Secretariat of which is held by BSI. 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 July 1999, and conflicting national standards shall be withdrawn at the

16、 latest by 1 December 2003. This European Standard is one of a series of standards for tests for general properties of aggregates. Test methods for other properties of aggregates are covered by Parts of the following European Standards: EN 933, Tests for geometrical properties of aggregates. EN 1097

17、, Tests for mechanical and physical properties of aggregates. EN 1367, Tests for thermal and weathering properties of aggregates. EN 1744, Tests for chemical properties of aggregates. prEN 13179, Tests for filler aggregate used in bituminous mixtures. The other parts of EN 932 will be: Part 1: Metho

18、ds for sampling. Part 3: Procedure and terminology for simplified petrographic description. Part 5: Common equipment and calibration. Part 6: Definitions of repeatability and reproducibility. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following cou

19、ntries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Contents Page Foreword 2 1 Scope 3 2 Normative ref

20、erences 3 3 Definitions and symbols 3 4 Principle 3 5 Apparatus 3 6 Consideration before sample reduction 5 7 Sample reduction technique using a rotary sample divider 5 8 Sample reduction using a riffle box 5 9 Sample reduction using fractional shovelling 7 10 Sample reduction by quartering 7 11 Sam

21、ple reduction to a test portion of a specified mass within a small tolerance 8 12 Sample reduction with crushing to reduce the particle size 8 13 Procedures for obtaining duplicate test portions 8 Annex A (informative), and divisions by a riffle box 9 Annex B (informative) Worked examples 10Page 3 E

22、N 932-2:1999 BSI 05-1999 NOTE The dashed lines denote dividing of a sample into two subsamples. Figure 1 division 1 Scope This European Standard specifies methods for reducing laboratory samples of aggregates to test portions, when the test portion mass is: specified by a lower limit on the mass; sp

23、ecified by a tolerance around a target mass; determined precisely by the requirements of a test method. 2 Normative references This European Standard incorporates, by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the

24、 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 incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to ap

25、plies. EN 932-1, Tests for general properties of aggregates Part 1: Methods for sampling. prEN 932-5, Tests for general properties of aggregates Part 5: Common equipment and calibration. 3 Definitions and symbols 3.1 Definitions For the purposes of this European Standard, the following definitions a

26、pply: 3.1.1 laboratory sample sample intended for laboratory testing 3.1.2 subsample sample obtained by means of a sample reduction procedure 3.1.3 test portion subsample used as a whole in a single test 3.1.4 test specimen sample used in a single determination when a test method requires more than

27、one determination of a property 3.1.5 division division of a sample into two subsamples of approximately equal mass (see Figure 1) 3.1.6 division division of a sample into two subsamples, with masses approximately and times the mass of the original sample (see Figure 2) 3.1.7 division division of a

28、sample into two subsamples with masses approximately and times the mass of the original sample (see Figure 3). 3.2 Symbols m L laboratory sample mass (in grams or kilograms). m S subsample mass (in grams or kilograms). m T specified test portion mass (in grams or kilograms). 4 Principle The procedur

29、es given in this European Standard are designed so that test portions are obtained by the minimum number of division steps, and so that, as far as possible, the operator is prevented from making small adjustments to the test portion and from choosing the particles that go into the test portion. 5 Ap

30、paratus Apparatus shall be as specified in EN 932-1 with the addition of suitable apparatus for crushing and grinding. All apparatus shall comply with the general requirements of prEN 932-5. NOTE In all cases, alternative designs may be used so long as the essential dimensions of width of opening an

31、d length are met, and the devices can be used to fulfil the sample reduction methods specified in clauses 7 to 13.Page 4 EN 932-2:1999 BSI 05-1999 NOTE The dashed lines denote dividing of a sample into two subsamples. A dotted line denotes the addition of a subsample retained from a previous divisio

32、n stage. Figure 2 division NOTE The dashed lines denote dividing of a sample into two subsamples. A dotted line denotes the addition of a subsample retained from a previous division stage Figure 3 divisionPage 5 EN 932-2:1999 BSI 05-1999 6 Consideration before sample reduction 6.1 Moisture content a

33、nd homogeneity of the sample When the moisture content of an aggregate is to be determined, one or more test portions shall be taken prior to drying. A riffle box or a mechanical divider shall not be used. When test portions are required for other purposes than moisture content and a riffle box or m

34、echanical divider is to be used, the laboratory sample shall be brought to a condition in which it is free-flowing. NOTE 1 For aggregates containing fines that segregate when dry, or for aggregates containing lumps of clay visible to the naked eye, it is recommended that they are subjected to sample

35、 reduction in the condition in which they are received at the laboratory, not dried. NOTE 2 If on the basis of visual inspection, the laboratory sample needs mixing, then this should be performed on a sampling tray. For aggregate that contains a wide range of particle sizes it can be desirable to se

36、parate the laboratory sample into two (or more) fractions by sieving and to treat each fraction to sample reduction separately. 6.2 Test methods that specify only a lower limit to the test portion mass For test methods that specify only a minimum mass (m T ) for the test portion or each of several t

37、est specimens one of the following procedures to yield 100 % to 150 % of the specified mass shall be used: a) sample reduction using a rotary sample divider (see clause 7); b) sample reduction using a riffle box (see clause 8); c) sample reduction using fractional shovelling (see clause 9); d) sampl

38、e reduction by quartering (see clause 10). NOTE a) above is the preferred procedure and d) is not recommended for wide gradings. 6.3 Test methods that allow a sizeable tolerance round a target mass For test methods, which require a test portion mass suited to the capacity of the equipment that is us

39、ed, but can allow a sizeable tolerance around the test portion mass (for example, determination of water-soluble sulfates), one of the following procedures that gives a test portion mass within 15 % of the specified mass shall be used: a) sample reduction using a rotary sample divider (see clause 7)

40、; b) sample reduction using a riffle box (see clause 8); c) sample reduction using fractional shovelling (see clause 9). NOTE a) above is the preferred procedure. 6.4 Test methods that specify a test portion mass within a small tolerance For the following types of test methods, which require a test

41、portion mass to be within a small tolerance of a specified mass, the procedure specified in clause 11 shall be used: a) test methods for which the test portion mass is determined by the capacity of a container used in the test (for example, bulk density); b) test methods that involve the manufacture

42、 of specimens (for example mortar or bituminous bound or hydraulically bound test specimens) from aggregate fractions that have to be weighed to the nearest 5 g or less; c) test methods where the test portion mass is specified with a very narrow tolerance. 7 Sample reduction technique using a rotary

43、 sample divider Select a configuration of the sample divider that will yield the test portions within 100 % to 150 % of the specified mass, or within 85 % to 115 % of the specified mass, as appropriate to the test method requirements. NOTE The calculations and schemes of sample reduction divisions u

44、sing a riffle box given in clause 8 can also be applied to a rotary sample divider provided it can divide into a small and even number of subsamples. Place the sample into the hopper and start the rotor. When the rotor is rotating at its operating speed start the vibrating feeder. Check that at leas

45、t 35 revolutions are completed before the laboratory sample is exhausted. If this is not achieved, recombine the subsamples and repeat the sample reduction with a lower feed rate. If the mechanical sample divider is not equipped with a feeder and/or 35 revolutions cannot be achieved, the mass of eac

46、h portion shall be checked and shall be within 100 % to 150 % of the specified mass, or within 85 % to 115 % of the specified mass as appropriate. 8 Sample reduction using a riffle box Put the sample into one of the riffle box receptacles. Spread the material out evenly over the full length of the r

47、eceptacle. Place the other two receptacles in position. Pour the sample from the long side of the riffle box down the centre line of the riffle box. An example of the division steps using a riffle box is shown in annex A. 8.1 To provide a test portion mass within 100 % to 150 % of a specified mass 8

48、.1.1 Calculations Obtain the value of the specified test portion mass m T from the test method and calculate 0,75 m T and 1,5 m T . NOTE If a test method is performed frequently then it may be convenient to display the pertinent information in the laboratory where the sample reduction is carried out

49、, see Figure B.1. Determine the mass of the laboratory sample, m L . Calculate m S = m L /2, m L /4, m L /8, m L /16, until a mass m S is obtained that is less than 1,5 m T .Page 6 EN 932-2:1999 BSI 05-1999 Figure 4 Sample reduction procedure for 8.1 8.1.2 Sample reduction (see Figure 4) If m S is between 0,75 m T to m T reduce the laboratory sample by one division operation and then proceed using divisions to obtain the required test portion mass; if m S is between m T to 1,5 m T proceed using