1、 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58methods Part 12: Determination of the alkali content of admixturesThe European Standard EN 480-12:2
2、005 has the status of a British StandardICS 91.100.10; 91.100.30Admixtures for concrete, mortar and grout Test BRITISH STANDARDBS EN 480-12:2005BS EN 480-12:2005This British Standard was published under the authority of the Standards Policy and Strategy Committee on 25 November 2005 BSI 25 November
3、2005ISBN 0 580 47319 8Cross-referencesThe British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI El
4、ectronic Catalogue or of British Standards Online.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations.Summary of pagesT
5、his document comprises a front cover, an inside front cover, the EN title page, pages 2 to 9 and a back cover.The BSI copyright notice displayed in this document indicates when the document was last issued.Amendments issued since publicationAmd. No. Date CommentsA list of organizations represented o
6、n this subcommittee can be obtained on request to its secretary. present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments and promulgate them in th
7、e UK.National forewordThis British Standard is the official English language version of EN 480-12:2005. It supersedes BS EN 480-12:1998 which is withdrawn.The UK participation in its preparation was entrusted by Technical Committee B/517, Concrete, to Subcommittee B/517/3, Admixtures, which has the
8、responsibility to: aid enquirers to understand the text;EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 480-12October 2005ICS 91.100.10; 91.100.30 Supersedes EN 480-12:1997 English VersionAdmixtures for concrete, mortar and grout - Test methods - Part12: Determination of the alkali content of admi
9、xturesAdjuvants pour bton, mortiers et coulis - Mthodes dessai- Partie 12: Dtermination de la teneur en alcalis dans lesadjuvantsZusatzmittel fr Beton, Mrtel und Einpressmrtel -Prfverfahren - Teil 12: Bestimmung des Alkaligehalts vonZusatzstoffenThis European Standard was approved by CEN on 28 July
10、2005.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained o
11、n application to the Central Secretariat or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat
12、has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slo
13、vakia,Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2005 CEN All rights of exploitation in any form and by any means reservedworldwide fo
14、r CEN national Members.Ref. No. EN 480-12:2005: EEN 480-12:2005 (E) 2 Contents Page Foreword 3 1 Scope .4 2 Normative references .4 3 Principle.4 4 Reagents5 5 Apparatus 6 6 Preparation of calibration graphs6 7 Test procedure 6 8 Test report .8 Bibliography.9 EN 480-12:2005 (E) 3 Foreword This Europ
15、ean Standard (EN 480-12:2005) has been prepared by Technical Committee CEN/TC 104 “Concrete 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 la
16、test by April 2006, and conflicting national standards shall be withdrawn at the latest by April 2006. It has been drafted by Subcommittee 3 (SC 3) of TC 104 “Admixtures for concrete, mortar and grout“. This document is part of the series EN 480 “Admixtures for concrete, mortar and grout Test method
17、s“ which comprises the following Part 1 Reference concrete and reference mortar for testing Part 2 Determination of setting time Part 4 Determination of bleeding of concrete Part 5 Determination of capillary absorption Part 6 Infrared analysis Part 8 Determination of the conventional dry material co
18、ntent Part 10 Determination of water soluble chloride content Part 11 Determination of air void characteristics in hardened concrete Part 12 Determination of the alkali content of admixtures Part 13 Reference masonry mortar for testing mortar admixtures Part 14 Admixtures for concrete, mortar and gr
19、out - Test methods - Part 14: Measurement of corrosion susceptibility of reinforcing steel in concrete - Potentiostatic electro-chemical test method 1)This document is applicable together with the other standards of the EN 480 series. This document supersedes EN 480-12:1997. According to the CEN/CEN
20、ELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Mal
21、ta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. 1) This part is under preparation EN 480-12:2005 (E) 4 1 Scope This document specifies a method for the determination of the alkali (sodium and potassium) content of admixtures for concrete,
22、 mortar and grouts in accordance with the series EN 934. 2 Normative references The following referenced documents are 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 (incl
23、uding any amendments) applies. EN 196-2, Methods of testing cement Determination of the chloride, carbon dioxide and alkali content of cement. ISO 648, Laboratory glassware One-mark pipettes. ISO 1042, Laboratory glassware One-mark volumetric flasks. 3 Principle An atomic absorption spectrophotomete
24、r is used to measure the sodium and potassium in dilute nitric acid extracts from admixtures. The extract is nebulised into an air/acetylene flame and the absorption of sodium or potassium radiation as it passes through the flame is measured. The amount of absorption is directly proportional to the
25、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 (alkali) content. As an alternative to an atomic absorption spectro-photometer a suitabl
26、e calibrated flame photometer can be used for the determination of sodium and potassium in the test solutions prepared in accordance with this document. EN 480-12:2005 (E) 5 4 Reagents 4.1 Concentrated nitric acid, analytical reagent diluted 1: 1 with water (4.2). 4.2 Distilled, de-ionised or demine
27、ralised water. The same source of water shall be used for preparation of calibration solutions and sample extracts. 4.3 Sodium stock solution (100 mg Na2O per litre). Dissolve 0,188 g sodium chloride, analytical reagent grade, dried at (105 5) C to constant mass, in water (4.2), dilute to 1 litre in
28、 a volumetric flask (5.2) with water2). 4.4 Potassium stock solution (100 mg K2O per litre). Dissolve 0,158 g potassium chloride, analytical reagent grade, dried at (105 5) C to constant mass, in water (4.2), dilute to 1 litre in a volumetric flask (5.2) with water2). 4.5 Calibration solution3). Mea
29、sure 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 water and air tight closu
30、re (5.5). Table 1: Calibration solutions Na2O and K2O concentration Sodium stock solution (4.3) Potassium stock solution (4.4) Nitric Acid (4.1)mg/l ml ml ml 0 0 0 102,5 25 25 10 5 50 50 102) Commercially available calibrated solutions for spectroscopic applications may be used. 3) The volumes of st
31、ock solutions given in Table 1 may not be appropriate when commercially available spectroscopic solutions 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 a
32、ccordingly. EN 480-12:2005 (E) 6 5 Apparatus 5.1 Balance with a capacity of up to 200 g readable to 0,1 mg. 5.2 100 ml and 1 litre volumetric flasks of class A in accordance with ISO 1042. 5.3 Calibrated pipettes of class A in accordance with ISO 648. 5.4 10 ml and 25 ml measuring cylinders. 5.5 1 l
33、itre plastic bottles with water and air tight closure. The plastic shall be such that no sodium or potassium is leached into 1 % nitric acid solution over a period of 6 months. 5.6 Atomic absorption spectrophotometer (AAS) equipped with burners suitable for air/acetylene flames and with a combinatio
34、n Na/K hollow cathode lamp or separate Na and K lamps. 5.7 A flame photometer (according to EN 196-2) if alternatively used in accordance with Clause 3. 6 Preparation of calibration graphs Operate the AAS or the flame photometer in accordance with the manufacturers instructions. Whilst spraying wate
35、r adjust the wave length 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 % absorption and then in
36、 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 calibration instructions. 7
37、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 (5.2) with 150 to 250 ml wate
38、r (4.2) 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 to 250 ml water (4.2) and 10 ml nitric acid (4.1)
39、. Heat to near boiling on a hot plate and maintain at near boiling for (15 5) minutes. 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 wash thoroughly wit
40、h water collecting the filtrate and washings in the volumetric flask. EN 480-12:2005 (E) 7 Transfer to a 1 litre volumetric flask (5.2), dilute to the mark with water (4.2) and mix thoroughly. 7.2 Measurement of sodium and potassium Operate the AAS in accordance with the manufacturers instructions w
41、ith the Na/K lamp in place. Whilst spraying water adjust the wave length setting 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 m
42、g/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 wave length 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 Results Calculate the Na2O and K2O content of the admixture from the following equations: massby % 100 x = cont
45、ent ONa122Dmm(1) massby % 100 x = content OK132Dmm(2)Where m1mass of admixture sample in mg m2mass of Na2O in mg m3mass of K2O 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
46、+ 0,658 K2O content % by mass Report the total Na2O equivalent content in percent per 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
47、from 1,0 % to 3,5 % Na2O equivalent. EN 480-12:2005 (E) 8 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 the equipment; f) Origin of the sample and date when taken; g) Sodiu
48、m oxide content; h) Potassium oxide content; i) Sodium oxide equivalent content. EN 480-12:2005 (E) 9 Bibliography 1 EN 934-2, Admixtures for concrete, mortar and grout Part 2: Concrete admixtures Definitions, requirements, conformity, marking and labelling. 2 EN 934-3, Admixtures for concrete, mort
49、ar and grout Part 3: Admixtures for mortar - Definitions, requirements, conformity, marking and labelling. 3 EN 934-4, Admixtures for concrete, mortar and grout Part 4: Admixtures for grout for prestressing tendons - Definitions, requirements, conformity, marking and labelling. 4 EN 934-5, Admixtures for concrete, mortar and grout Part 5: Admixtures for sprayed concrete - Definitions, requirements, conformity, marking and labelling. blankBS EN BSI389 Chiswick High RoadLondonW4 4AL480-12:2
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