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1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS EN 480-12 : 1998 The E
2、uropean Standard EN 480-12 : 1997 has the status of a British Standard ICS 91.100.10; 91.100.30 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Admixtures for concrete, mortar and grout Test methods Part 12. Determination of the alkali content of admixtures Licensed Copy: shef
3、fieldun sheffieldun, na, Sat Nov 04 09:25:42 GMT+00:00 2006, Uncontrolled Copy, (c) BSI This British Standard, having been prepared under the 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 March 1
4、998 BSI 1998 ISBN 0 580 29246 0 BS EN 480-12 : 1998 Amendments issued since publication Amd. No.DateText affected National foreword This Part of BS EN 480 has been prepared by Subcommittee B/517/3 and is the English language version of EN 480-12 : 1997, published by the European Committee for Standa
5、rdization (CEN). This standard is part of a package of standards comprising BS EN 480 : Parts 1, 2, 4, 5, 6, 8, 10, 11 and 12, and BS EN 934 : Parts 2 and 6. When all the standards in this package have been published, BS 5075 : Parts 1, 2 and 3 will be amended by deleting clauses which conflict with
6、 standards in the package. A list of 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 unde
7、r the section entitled International 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 applic
8、ation. Compliance with a British 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 4, an inside back cover and a back cover. Licensed Copy: sheffieldun sheffieldun, na, Sat
9、Nov 04 09:25:42 GMT+00:00 2006, Uncontrolled Copy, (c) BSI CEN European Committee for Standardization Comite Europe en de Normalisation Europa isches Komitee fu r Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1997 CEN All rights of exploitation in any form and by any means reserve
10、d worldwide for CEN national Members. Ref. No. EN 480-12 : 1997 E EUROPEAN STANDARDEN 480-12 NORME EUROPE ENNE EUROPA ISCHE NORM October 1997 ICS 91.100.10; 91.100.30 Descriptors: Construction materials, concrete admixtures, concrete, mortars: material, grouting, analysis method, determination, alka
11、li, sodium, potassium English version Admixtures for concrete, mortar and grout Test methods Part12: Determination of the alkali content of admixtures Adjuvants pour be ton, mortier et coulis Me thodes dessai Partie 12: De termination de la teneur en alcalins dans les adjuvants Zusatzmittel fu r Bet
12、on, Mo rtel und Einpremo rtel Pru fverfahren Teil 12: Bestimmung des Alkaligehalts von Zusatzstoffen This European Standard was approved by CEN on 3 April 1997. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard
13、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 Standard exists in three official versions (English, French, Germ
14、an). 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, Belgium, Czech Republic, Denmark, Fi
15、nland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. Licensed Copy: sheffieldun sheffieldun, na, Sat Nov 04 09:25:42 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Page 2 EN 480-12 : 1997 BSI 1998 Foreword This
16、 European Standard has been prepared by Technical Committee CEN/TC 104, Concrete (performance, production, placing and compliance criteria), the Secretariat of which is held by DIN. This standard has been prepared by Subcommittee 3 (SC 3) of TC 104, Admixtures for concrete, mortar and grout. The pre
17、sent standard is applicable together with the standards of the series EN 480 and EN 934. 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 April 1998, and conflicting national standards shall be wit
18、hdrawn at the latest by April 1998. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy,
19、Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Contents Page Foreword2 1Scope3 2Normative references3 3Principle3 4Reagents3 5Apparatus3 6Preparation of calibration graphs4 7Test procedure4 8Test report4 Licensed Copy: sheffieldun sheffieldun, na, Sat N
20、ov 04 09:25:42 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Page 3 EN 480-12 : 1997 BSI 1998 1) Commercially available calibrated solutions for spectroscopic applications may be used. 2) The volumes of stock solutions given in table 1 may not be appropriate when commercially available spectroscopic so
21、lutions are used. In addition, some atomic absorption spectrophotometers may require a smaller range of Na2O and K2O concentration for calibration and use. In this case modify the calibration solutions accordingly. 1 Scope This European Standard specifies a method for the determination of the alkali
22、 (sodium and potassium) content of admixtures for concrete, mortar and grouts in accordance with the series EN 934. 2 Normative references This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate pl
23、aces in the 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 ref
24、erred to applies. EN 196-21 Methods of testing cement Determination of the chloride, carbon dioxide and alkali content of cement EN 934-2Admixtures for concrete, mortar and grout Part 2: Concrete admixtures Definitions and requirements ISO 648Laboratory glassware One-mark pipettes ISO 1042Laboratory
25、 glassware One-mark volumetric flasks 3 Principle An atomic absorption spectrophotometer is used to measure the sodium and potassium in dilute nitric acid extracts from admixtures. The extract is nebulized into an air/acetylene flame and the absorption of sodium or potassium radiation as it passes t
26、hrough the flame is measured. The amount of absorption is directly proportional to the sodium or potassium content of the extract at low concentrations. The sodium and potassium contents are separately measured and their sum, proportioned by molecular mass, is reported as the total equivalent Na2O (
27、alkali) content. As an alternative to an atomic absorption spectrophotometer a suitable calibrated flame photometer can be used for the determination of sodium and potassium in the test solutions prepared in accordance with this standard. 4 Reagents a) Concentrated nitric acid, analytical reagent gr
28、ade 1:1. b) Distilled or deionized water. The same source of water shall be used for preparation of calibration solutions and sample extracts. c) Sodium stock solution, (100 mg Na2O per litre). Dissolve 0,188 g sodium chloride, analytical reagent grade, dried at (1055) 8C to constant mass, in water
29、(4b), dilute to 1 litre in a volumetric flask (5b) with water1). d) Potassium stock solution, (100 mg K2O per litre). Dissolve 0,158 g potassium chloride, analytical reagent grade, dried at (1055) 8C to constant mass, in water (4b), dilute to 1 litre in a volumetric flask (5b) with water1). e) Calib
30、ration solution2). Measure the required volume of stock solution shown in table 1 with a pipette and nitric acid with a plastic measuring cylinder. Transfer to a 1 litre graduated volumetric flask and dilute to the mark with water. Mix thoroughly and transfer to a clean dry plastic bottle with a wat
31、er- and air-tight closure as described in 5e. Table 1. Calibration solutions Na2O and K2O concentration Sodium stock solution (4c) Potassium stock solution (4d) Nitric acid (4a) mg/lmlmlml 00010 2,5252510 5505010 5 Apparatus a) Balance, with a capacity of up to 200 g readable to 0,1 mg. b) 100 ml an
32、d 1 litre volumetric flasks, of class A in accordance with ISO 1042. c) Calibrated pipettes, of class A in accordance with ISO 648. d) 10 ml and 25 ml measuring cylinders. e) 1 litre plastic bottles, with water- and air-tight closure. The plastic shall be such that no sodium or potassium is leached
33、into 1 % nitric acid solution over a period of 6 months. f) Atomic absorption spectrophotometer (AAS), equipped with burners suitable for air/acetylene flames and with a combination Na/K hollow cathode lamp or separate Na and K lamps. g) A flame photometer, (according to EN 196-21), if alternatively
34、 used in accordance with clause 3. Licensed Copy: sheffieldun sheffieldun, na, Sat Nov 04 09:25:42 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Page 4 EN 480-12 : 1997 BSI 1998 6 Preparation of calibration graphs Operate the AAS or the flame photometer in accordance with the manufacturers instructions
35、. Whilst spraying water adjust the wavelength setting around 589 nm (for Na) to give the maximum signal on the detector. Spray the 5,0 mg/l calibration solution and adjust burner height and acetylene flow to give maximum absorption. Spray the 0 mg/l solution and adjust the gain control to give 0 % a
36、bsorption and then in turn spray the other calibration solutions and record the absorption for each one. Repeat the operation at a wavelength setting around 768 nm (for K). Some instruments may be used in direct readout concentration mode. When this procedure is used follow the manufacturers calibra
37、tion instructions. 7 Test procedure 7.1 Preparation of test solution 7.1.1 Liquid admixture Mix the samples thoroughly and transfer approximately 1 ml to a pre-weighed weighing boat. Record the mass of admixture sample in mg to the nearest 0,1 mg (m1). Transfer to a 1 litre volumetric flask (5b) wit
38、h 150 ml to 250 ml water (4b) and add 10 ml nitric acid. Dilute to the mark with water. Mix thoroughly. 7.1.2 Powder admixtures Mix the sample thoroughly and weigh approximately 1 g, recording the actual mass in mg to 0,1 mg (m1). Transfer to a 500 ml glass beaker, add 150 ml to 250 ml water (4b) an
39、d 10 ml nitric acid (4a). Heat to near boiling on a hot plate and maintain at near boiling for (155) min. Remove from the source of heat and cool to room temperature. Complete dissolution is not necessary. If any insoluble residue remains, filter the solution through a medium grade filter paper and
40、wash thoroughly with water, collecting the filtrate and washings in the volumetric flask. Transfer to a 1 litre volumetric flask (5b), dilute to the mark with water (4b) and mix thoroughly. 7.2 Measurement of sodium and potassium Operate the AAS in accordance with the manufacturers instructions with
41、 the Na/K lamp in place. Whilst spraying water adjust the wavelength setting to around 589 nm (for Na) to give the maximum signal to the detector. Use the burner height and fuel settings established in the calibration procedure. Adjust the gain control to give 0 % absorption whilst spraying the 0 mg
42、/l calibration solution. Spray one or more calibration solutions to confirm that the calibration graph is valid. If necessary prepare a new graph. Spray the sample solution and record the absorption. Refer to the calibration graph and record the concentration of the sample solution in mg Na2O/litre.
43、 If the absorption is off scale prepare a diluted extract by transferring 10,0 ml of the sample solution into a 100 ml volumetric flask and dilute to the mark with the 0 mg/l calibration solution, i.e. dilution D = 10. Mix thoroughly and repeat the procedure. Further dilutions may be required. Recor
44、d mass m2of Na2O in mg in 1 litre of solution. Reset the wavelength control to around 768 nm (for K) and repeat the above procedure. Record mass m3of K2O in mg in 1 litre of solution. 7.3 Calculation of results Calculate the Na2O and K2O content of the admixture from the following equations: (1)Na2O
45、 content =3 100 D % by mass m2 m1 (2)K2O content =3 100 D % by mass m3 m1 Where m1= mass of admixture sample in mg and D = the dilution used, if necessary. Calculate the total equivalent alkali content of the admixture from the following equation: Total Na2O equivalent = Na2O content + 0,658 K2O con
46、tent % by mass Report the total Na2O equivalent content in percent by mass to the nearest 0,1 %. NOTE. From 12 sets of results from different laboratories, after rejecting one set as outliers, the coefficient of variation was found to be 5 % of the mean for alkali contents in a range from 1,0 % to 3
47、,5 % Na2O equivalent. 8 Test report a) name or code of admixture tested (with information relating to its marking); b) date of the test; c) name of the laboratory; d) name of operator; e) type of equipment; f) origin of the sample and date when taken; g) sodium oxide content; h) potassium oxide cont
48、ent; i) sodium oxide equivalent content. Licensed Copy: sheffieldun sheffieldun, na, Sat Nov 04 09:25:42 GMT+00:00 2006, Uncontrolled Copy, (c) BSI blank Licensed Copy: sheffieldun sheffieldun, na, Sat Nov 04 09:25:42 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BSI 389 Chiswick High Road London W4 4A
49、L | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 Charter. Revisions British Standards are updated by amendment
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