SANS 6243-2008 Deleterious clay content of the fines in aggregate (methylene blue adsorption indicator test)《细骨料中的有害粘土含量(亚甲基蓝吸附指示剂试验)》.pdf

1、 Collection of SANS standards in electronic format (PDF) 1. Copyright This standard is available to staff members of companies that have subscribed to the complete collection of SANS standards in accordance with a formal copyright agreement. This document may reside on a CENTRAL FILE SERVER or INTRA

2、NET SYSTEM only. Unless specific permission has been granted, this document MAY NOT be sent or given to staff members from other companies or organizations. Doing so would constitute a VIOLATION of SABS copyright rules. 2. Indemnity The South African Bureau of Standards accepts no liability for any

3、damage whatsoever than may result from the use of this material or the information contain therein, irrespective of the cause and quantum thereof. ISBN 978-0-626-21531-6 SANS 6243:2008Edition 1.2Any reference to SABS SM 1243 is deemedto be a reference to this standard(Government Notice No. 1373 of 8

4、 November 2002)SOUTH AFRICAN NATIONAL STANDARD Deleterious clay content of the fines in aggregate (methylene blue adsorption indicator test) Published by SABS Standards Division 1 Dr Lategan Road Groenkloof Private Bag X191 Pretoria 0001 Tel: +27 12 428 7911 Fax: +27 12 344 1568 www.sabs.co.za SABS

5、SANS 6243:2008 Edition 1.2 Table of changes Change No. Date Scope Amdt 1 2002 Amended to update normative references. Amdt 2 2008 Amended to change the designation of SABS standards to SANS standards, and to delete a footnote. Foreword This South African standard was approved by National Committee S

6、ABS SC 59A, Construction standards Cement, lime and concrete, in accordance with procedures of the SABS Standards Division, in compliance with annex 3 of the WTO/TBT agreement. This document was published in October 2008. This document supersedes SABS SM 1243:2002 (edition 1.1). A vertical line in t

7、he margin shows where the text has been technically modified by amendment No. 2. SANS 6243:2008 Edition 1.2 1 Deleterious clay content of the fines in aggregate (methylene blue adsorption indicator test) 1 Scope and field of application This standard specifies a rapid qualitative means for determini

8、ng whether the clay content of the fines of an aggregate contains deleterious swelling clay minerals, such as smectites, which are usually results of the weathering of rock. The method also indicates to what extent an aggregate requires to be further investigated to determine its suitability for spe

9、cific applications. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this standard. All standards are subject to revision and, since any reference to a standard is deemed to be a reference to the latest edition of that

10、standard, parties to agreements based on this standard are encouraged to take steps to ensure the use of the most recent editions of the standards indicated below. Information on currently valid national and international standards can be obtained from the SABS Standards Division. SANS 197, Preparat

11、ion of test samples of aggregates. SANS 3310-1/ISO 3310-1, Test sieves Technical requirements and testing Part 1: Test sieves of metal wire cloth. Amdt 1 SANS 3310-2/ISO 3310-2, Test sieves Technical requirements and testing Part 2: Test sieves of perforated metal plate. Amdt 1 SANS 5832, Organic im

12、purities in fine aggregates (limit test). 3 Reagents 3.1 Methylene blue, analytical reagent (in the trihydrate form), kept in a dry and dark place. 3.2 Indicator solution, that consists of 0,1 g of methylene blue dissolved in distilled water and made up to 100 mL. The solution will remain stable for

13、 2 weeks, after which it should be discarded. 3.3 Water, distilled or deionized. 3.4 Hydrogen peroxide, 30 % by mass. SANS 6243:2008 Edition 1.2 2 4 Apparatus 4.1 Burette, of capacity 25 mL, mounted on a stand. 4.2 Erlenmeyer flask, of capacity 250 mL. 4.3 Filter paper1), medium textured quantitativ

14、e. Amdt 2 4.4 Test sieves, of nominal aperture sizes 425 m and 75 m, and that comply with the requirements of SANS 3310-1 or SANS 3310-2. Amdt 1 5 Procedure 5.1 Take a sample of aggregate of approximately 1 kg (see SANS 197) and dry-sieve it on a 75 m sieve protected by a 425 m sieve. 5.2 If the sam

15、ple fails the test for organic impurities (see SANS 5832), take a representative specimen of approximately 5 g from the material that passed the 75 m sieve, boil it for approximately 0,5 h in sufficient hydrogen peroxide in a glass beaker of suitable capacity and height and allow the whole to cool t

16、o room temperature. Wash the material in the beaker by adding water almost to the rim and stirring the contents vigorously. Allow the whole to stand undisturbed until the supernatant liquid is clear and contains no solid particles. Carefully decant the clear liquid, ensuring that no solid material i

17、s lost. Repeat the process of washing and decanting a further two times. Dry the residue to constant mass at a temperature of 100 C to 110 C and cool it to room temperature. 5.3 From the material that passed the 75 m sieve, take a representative specimen of 1 g (untreated or treated, as relevant (se

18、e 5.2), weighed to the nearest 0,01 g (mass M ), place it in the Erlenmeyer flask, add 30 mL 1 mL of water and disperse the specimen by vigorously swirling and shaking the flask. 5.4 Titration 5.4.1 Titrate successions of 0,5 mL of the indicator solution to the dispersion in the Erlenmeyer flask, us

19、ing the burette. After each addition of the indicator, agitate the contents of the flask for 1 min, remove a drop of the dispersion with a glass rod and dab it carefully on a sheet of filter paper (see 4.3). Initially, a spot that is dark blue in colour, with a distinct edge, surrounded by a ring of

20、 clear water, is formed. 5.4.2 When the edge of a spot appears fuzzy or is surrounded by a narrow light-blue halo (or both), agitate the flask for a further 1 min and carry out another spot test. 5.4.3 If the halo disappears, add another 0,5 mL of the indicator solution to the contents of the flask,

21、 agitate it as before and carry out another spot test. 5.4.4 If the halo persists, agitate the flask for a further 2 min and repeat the spot test. 5.4.5 Whatever the outcome of the spot test as described in 5.4.1 to 5.4.4, add further volumes of 0,5 mL of indicator solution at a time, followed by ag

22、itation for 2 min, spot test and then agitate again for 2 min and spot test. Repeat this sequence, with a total of 4 min of agitation, until a definite blue halo is observed. 1) Whatman No. 40 or equivalent. Amdt 2 SANS 6243:2008 Edition 1.2 3 5.4.6 Record each successive addition of indicator solut

23、ion by appropriate marking of the filter paper on which spot tests are carried out. 5.4.7 By holding the filter paper up against natural light while it is still damp, determine the volume of indicator solution (volume V ) added that caused a blue halo to appear persistently for the first time. 6 Exp

24、ression and reporting of results 6.1 Calculate the methylene blue adsorption value MBV (percentage of methylene blue adsorbed), as follows: ( 0,10)=VMBVMwhere V is the total volume of indicator solution added, in millilitres (see 5.4.7); and M is the mass of the sample tested, in grams (see 5.3). 6.2 Report the methylene blue adsorption value (MBV) to the nearest 0,1. SABS