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1、BRITISH STANDARD BS EN 451-1:1995 Incorporating Corrigendum No. 1 Method of testing fly ash Part 1: Determination of free calcium oxide content The European Standard EN 451-1:1994 has the status of a British Standard ICS 91.100.30 BS EN 451-1:1995 This British Standard, having been prepared under th
2、e direction of the Sector Board for Building and Civil Engineering, was published under the authority of the Standards Board and comes into effect on 15 September 1995 BSI 04-1999 The following BSI references relate to the work on this standard: Committee reference B/516/101 Draft for comment 91/113
3、63 DC ISBN 0 580 24526 8 Committees responsible for this British Standard The preparation of this British Standard was entrusted by Technical Committee B/516, Cement and lime, to Subcommittee B/516/101, Pozzolanas, upon which the following bodies were represented: British Aggregate Construction Mate
4、rials Industries British Cement Association British Precast Concrete Federation British Ready Mixed Concrete Association Cementitious Slag Makers Association Department of the Environment (Building Research Establishment) Department of Transport Electricity Association Federation of Civil Engineerin
5、g Contractors Quality Ash Association Amendments issued since publication Amd. No.DateComments 10174September 1998 Indicated by a sideline in the margin BS EN 451-1:1995 BSI 04-1999i Contents Page Committees responsibleInside front cover National forewordii Foreword2 Text of EN 451-13 List of refere
6、ncesInside back cover BS EN 451-1:1995 ii BSI 04-1999 National foreword This Part of BS EN 451 has been prepared by Subcommittee B/516/101 and is the English language version of EN 451-1:1994 Method of testing fly ash Part 1: Determination of free calcium oxide content published by the European Comm
7、ittee for Standardization (CEN). This standard has been prepared as part of a package of standards harmonized within the member countries of CEN to support the essential requirements of the Construction Products Directive. BS EN 451-1 describes a method for the determination of free calcium oxide in
8、 fly ash by extraction with a mixture of ethyl acetoacetate and butan-2-ol followed by titration with hydrochloric acid using bromophenol blue as indicator. The method has been used successfully for the determination of free calcium oxide in Portland cements but there is limited experience in the UK
9、 of applying the method to fly ashes. There is a technical distinction between the various states in which calcium oxide may be present in ash, only that present as free calcium oxide having the potential to cause long-term unsoundness in concrete. Calcium oxide present as part of the glassy phase i
10、n ash, or otherwise bound in chemical compounds, does not lead to unsoundness. BS EN 451-1 supports BS EN 450 Fly ash for concrete Definitions, requirements and quality control. The national foreword to BS EN 450 explains the relationship between BS EN 450 and BS 3892-1. In particular, it is noted t
11、hat whilst both standards specify ashes arising from pulverized bituminous or other hard coals, BS EN 450 also permits ashes from sub-bituminous coals on a national basis. Ashes from such sub-bituminous coals, which do not occur in the UK, may contain free calcium oxide. However, the likelihood of f
12、ree calcium oxide being present in ashes from bituminous or other hard coals such as are specified in BS 3892-1 are remote. Hence whilst both BS EN 450 and BS 3892-1 include a requirement for the content of total calcium oxide, only the former includes a requirement for free calcium oxide. An autoco
13、ntrol maximum of 1.0 % is specified, although a value of up to 2.5 % is permitted provided that the ash complies with the requirement for soundness specified in BS EN 450. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are respon
14、sible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross-references Publication referred toCorresponding British Standard EN 196-7:1989BS EN 196-7:1992 Methods of testing cement Part 7: Methods of taking and preparing sa
15、mples of cement ISO 3534-1:1993BS ISO 3534 Statistics. Vocabulary and symbols BS ISO 3534-1:1993 Probability and general statistical terms Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, the EN title page, pages 2 to 4, an inside back cover and a back c
16、over. 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 451-1 September 1994 UDC 666.952.2:620.1:661.842.22 Descriptors: Fly ash,
17、chemical analysis, determination of content, calcium oxides English version Method of testing fly ash Part 1: Determination of free calcium oxide content Mthode dessai des cendres volantes Partie 1: Dtermination de la teneur en oxyde de calcium libre Prfverfahren fr Flugasche Teil 1: Bestimmung des
18、freien Calciumoxidgehalts This European Standard was approved by CEN on 1994-09-09. CEN members are bound to comply 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 an
19、d bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official version (English, French, German). A version in any other language made by translation under the responsibil
20、ity 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, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Port
21、ugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1996 Copyright reserved to CEN members Ref. No. EN 451-1:1994 E EN 451-1:1994 BSI 04-
22、1999 2 Foreword This European Standard was drawn up by the Technical Committee CEN/TC 104, Concrete, the Secretariat of which is held by DIN. The preparatory work was carried out by WG 4 of CEN/TC 104 since June 1988 in which the following countries participated: Austria, Belgium, Denmark, France, G
23、ermany, Ireland, Italy, Netherlands, Norway, Portugal, Sweden and United Kingdom. This European Standard has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association, and supports essential requirements of EC Directive(s). This European Standard s
24、hall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by March 1995, and conflicting national standards shall be withdrawn at the latest by March 1995. No existing European Standard is superseded. According to the CEN/CENELEC Int
25、ernal Regulations, 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, United Kingdom. Contents Page Foreword2 1Scope3 2Norm
26、ative references3 3General3 3.1Number of determinations3 3.2Repeatability and reproducibility3 3.3Expression of masses and volumes3 4Reagents3 5Apparatus3 6Procedure3 6.1Preparation of sample3 6.2Determination3 6.3Calculations4 7Results4 8Repeatability and reproducibility4 EN 451-1:1994 BSI 04-19993
27、 1 Scope This European Standard describes the procedure for the determination of free calcium oxide content in fly ash. The standard describes the reference procedure. If other methods are used it shall be shown that they give results equivalent to those obtained by the reference method. 2 Normative
28、 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 text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any
29、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 applies. EN 196-7:1989, Methods of testing cement Methods of taking and preparing samples of cement. ISO 565:1990, Tes
30、t sieves Woven metal wire cloth, perforated plate and electroformed sheet Nominal sizes of openings. ISO 3534-1:1993, Statistics Vocabulary and symbols Part 1: Probability and general statistical terms. 3 General 3.1 Number of determinations Carry out twice the procedure for determining the free cal
31、cium oxide content. If the difference between two determinations is more than twice the repeatability standard deviation, repeat the test and take the mean of the closest values. 3.2 Repeatability and reproducibility The standard deviations of repeatability and reproducibility, as defined in ISO 353
32、4, are expressed in absolute percentages by mass. 3.3 Expression of masses and volumes Express masses in grams to the nearest 0,0001 g and volumes from the burette in millilitres to the nearest 0,05 ml. 4 Reagents Use only reagents of analytical grade and distilled water, or water of equal purity. 4
33、.1 Butanoic acid, 3-oxo-ethyl ester (= ethyl acetoacetate). 4.2 Butan-2-ol. 4.3 Propan-2-ol. 4.4 Indicator (0,1 g of bromophenol blue in 100 ml of ethanol). 4.5 Hydrochloric acid (0,100 M). 5 Apparatus 5.1 Balance, capable of weighing to an accuracy of 0,0001 g or better. 5.2 Test sieve, with 0,063
34、mm sieve cloth conforming to ISO 565. 5.3 Mortar and pestle, or similar equipment for grinding. 5.4 Desiccator, containing a drying agent, e.g. silica gel. 5.5 Flask, 250 ml. 5.6 Spiral reflux condenser. 5.7 Absorption tube, filled with sodium hydroxide on an inorganic carrier (to protect the conten
35、ts of the flask and the condenser from reacting with atmospheric carbon dioxide). 5.8 Filter crucible, with pore sizes of 0,004 mm to 0,010 mm. NOTEAlternatively also a filter funnel, in which a filter paper with fine pores of a diameter of approximately 0,002 mm and a filter paper with medium pores
36、 of a diameter of approximately 0,007 mm can be placed, may be used. 6 Procedure 6.1 Preparation of sample Subdivide the laboratory sample, prepared in accordance with 6.2.2 of EN 450 by a suitable method to obtain a subsample of about 100 g. Pass this subsample through the test sieve (5.2). Grind a
37、ny residue in the mortar (5.3) until all the subsample passes through the sieve completely. Homogenize the total subsample and place it in the desiccator (5.4) until tested. 6.2 Determination Place a weighed portion of 1,0 g to 1,5 g of the subsample prepared in accordance with 6.1 into the 250 ml f
38、lask (5.5) and add a mixture of 12 ml butanoic acid, 3-oxo-ethyl ester (4.1) and 80 ml butan-2-ol (4.2). Fit the flask with the spiral reflux condenser (5.6) and the absorption tube (5.7) and boil for 1 h. Filter the warm mixture through the filter crucible (5.8). Wash the residue with propan-2-ol (
39、4.3) until the filtrate reaches a volume of 50 ml. If the filtrate is cloudy, reject it and repeat the extraction with a new weighed portion of the subsample. Add a few drops of bromophenol blue indicator (4.4) to the flitrate and titrate with hydrochloric acid (4.5) until the colour changes to yell
40、ow. Record the volume V of hydrochloric acid used. EN 451-1:1994 4 BSI 04-1999 6.3 Calculations The free calcium oxide content (WCaO), expressed as a percentage by mass of the dry fly ash, shall be calculated from the following equation: where 7 Results The mean value of two determinations, calculat
41、ed to two decimal places and expressed to one decimal place, shall be taken as the free calcium oxide content of the sample. 8 Repeatability and reproducibility The standard deviation for repeatability is 0,02 % by mass (provisional value). The standard deviation for reproducibility is 0,04 % by mas
42、s (provisional value). Cis the concentration (in mol/l) of the hydrochloric acid solution; Vis the volume (in ml) of hydrochloric acid solution used for titration; mis the weighed proportion (in g) of the dried fly ash. W CaO 28,04CV m1 000 -100= BS EN 451-1:1995 BSI 04-1999 List of references See n
43、ational foreword. BS EN 451-1:1995 BSI 389 Chiswick High Road London W4 4AL BSI British Standards Institution BSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal C
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