KENYA STANDARD                  KS 2 769-10: 2018 
                
   
        
 
 
 
 
 
 
  
 
 
 
 
 
 
 
 
Admixtures for  concrete, mortar and  grout 
Test methods  Part 10: Determination of water  
 
 
 
 
 
 
 
 
 
©KEBS 2018                         First  Edition 2018 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 KS 2 769-10: 201 8                                                                                                   
        
 
ii                     © KEBS 201 8 — All rights reserved  TECHNICAL COMMITEE REPRESENTATION  
 
The following organizations were represented on the Technical Committee:  
 
1. Architectural Association of  Kenya  
2. Bamburi Cement  
3. CHRYSO Eastern Africa Limited  
4. Concrete Products (K)Ltd  
5. Consumer Information Network  
6. Howards Humpreys East Africa LTD  
7. Institute of quantity surveyors of Kenya  
8. Kenya Industrial Research and Development Institute (KIRDI  
9. Kenya Institute of Highways and Building Technology (KIHBT)  
10. Ministry of Transport, Infrastructure, Housing and Urban Development.  
11. National Environment Management Authority  
12. National Housing Corporati on 
13. Technical University of Kenya  
14. University of Nairobi  
15. Kenya Bureau of Standards — Secretariat  
 
 
 
 
 
 
 
 
 
 
 
REVISION OF KENYA STANDARDS  
 
In order to keep abreast of progress in industry, Kenya Standards shall be regularly reviewed. Suggestions 
for improvemen ts to published standards, addressed to the Managing Director, Kenya Bureau of Standards, 
are welcome.  
 
 
 
 
 
 
 
 
 
 
© Kenya Bureau of Standards, 20 18 
  
Copyright. Users are reminded that by virtue of Section 25 of the Copyright Act, Cap. 12 of 2001  of the La ws of Kenya, copyright 
subsists in all Kenya Standards and except as provided under Section 26 of this Act, no Kenya Standard produced by Kenya Bure au of 
Standards may be reproduced, stored in a retrieval system in any form or transmitted by any means with out prior permission in writing 
from the Managing Director . 
 
 
 
 
 
 
 
 
 
 KENYA STANDARD                                  KS 2 770-10: 2018 
                
 © KEBS 201 8 — All rights reserved            iii  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Admixtures for  concrete, mortar and  grout 
Test methods  Part 10: Determination of water  
 
 
 
 
 
 
KENYA BUREAU OF STANDARDS (KEBS)  
 
Head Office:  P.O. Box 54974, Nairob i-00200, Tel.: (+ 254 020 ) 605490, 602350, Fax: (+254 020 ) 604031  
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 KS 2 769-10: 201 8                                                                                                   
        
 
iv                     © KEBS 201 8 — All rights reserved   
Foreword  
 
This Kenya Standard was revised  by the Concrete Technical Committee, under the guidance of the 
standards Projects Committee, and it is in accordance with the procedures of the  Kenya  Bureau  of 
Standards .  
This Kenya Standard is part of the series KS 2769  Admixtures for concrete, mortar and grout — Test 
methods which comprise  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 content  
 
— 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: Determination of the effect on corrosion susceptibility of reinforcing steel by potentiostatic  
electro -chemical test  
 
— Part 15: Reference concrete and method for testing viscosit y modifying admixtures  
 
This standard is applicable together with the standards of the series KS 2770  Admixtures for concrete, 
mortar  and grout.  
 
. 
 
 KENYA STANDARD                                  KS 2 770-10: 2018 
                
 © KEBS 201 8 — All rights reserved            5 KENYA  STANDARD                       KS 2769 -10:2018 
 
Admixtures for  concrete, mortar and  grout Test meth ods Part 10: 
Determination of water  
 
1. Scope  
 
This Standard specifies methods for determining water soluble halogens (except fluorides) in admixtures.  
 
The total water soluble halogen content is expressed as the chloride content.  
 
2.  Principle  
 
The object of t he test is to determine the content of chloride ions (including other halogen ions except 
fluorides) in an admixture by precipitation of the chloride ions with a silver nitrate solution, according to the reaction:  
 
Cl-+ Ag+  AgCl  (solid)  
 
The end point of  this reaction is determined with the aid of a pH meter.  
 
The volume of the sample required for this test has been calculated for an admixture of which the chloride 
content is lower than 0.1 % by mass. If the chloride content is known, or can be assumed to  be higher, the admixture 
has to be diluted in a precise ratio before carrying out the test.  
 
3.  Apparatus  
 
3.1. pH meter  
 
Either:  
a) a pH millivoltmeter in which case the graph is plotted point by point, or  
 
b) a recording pH millivoltmeter connected to an automatic b urette.  
 
 
3.2.  Electrodes  
Either:  
a) a combination of two electrodes consisting of:  
 
1) an indicator: silver;  
 
2) a reference: mercuric sulphate (electrolyte KNO 3) or calomel with agar gel (electrolyte KNO 3); or 
 
 
b) a combined electrode (indicator and reference) Ag - AgCI (electrolyte KNO 3). 
 
NOTE Other electrodes such as ion selective electrodes may be used provided the results will be unaffected  
. KS 2 769-10: 201 8                                                                                                           
 
6                     © KEBS 201 8 — All rights reserved  3.3.  Additional apparatus  
 
3.3.1.    Balance with an accuracy of 0.1 mg reading up to 200 g  
 
3.3.2.    20 ml burette graduated with accuracy of  0.05 ml  
 
3.3.3.    250 ml and 500 ml beakers  
 
3.3.4.  1 000 ml measuring flask  
 
3.3.5.     Heating device with a magnetic stirrer  
 
3.3.6.     10 ml, 20 ml and 50 ml graduated flasks  
 
3.4. Reagents  
 
All reagents shall be of analytical grade.  
 
3.4.1.  Concentrated nitric acid (HNO 3) 
 
3.4.2.  Hydrogen peroxide  (H2O2), 30 % by mass (110 volumes)  
 
3.4.3.  Sodium hydroxide solution ( NaOH), 33 % by mass  
 
3.4.4.  Distilled or demineralized water  
 
3.4.5.  Ethanol (C 2H5OH) 
 
3.4.6.  Acetone (C 3H70) 
 
3.4.7.  Silver nitrate solution (AgNO 3), pre -prepared 0.01 mol/l, normality N determined to ± 0.0001  
 
4. Procedur e 
 
4.1. Preparation of sample  
 
4.1.1.  Liquid admixture  
From a liquid admixture a sample of (10 ± 1) g is weighed to 0 .01 g and placed into a 250 ml or a 500 ml beaker.  
 
4.1.2.  Powder admixture  
From a powder admixture a sample (5 ± 1) g is weighed to 0.01 g. The sample is pla ced into a 250 ml or a 500 ml 
beaker.  
 
4.2. Determination  
 
4.2.1.  General  
Depending upon the composition of the admixture one of the following methods shall be used.                     KS 2 769-10: 201 8 
 
 
 
 4.2.2.  Method 1  
If the admixture does not contain constituents that will interfere with the test, such as l ignosulphonates, 
thiocyanates or reducing agents, dilute the sample or dissolve it and make the solution up to 100 nil with 
distilled or demineralized water. Then add 80 ml of acetone followed by dilute nitric acid until the pH is (2.0 + 
0.5) and carry out  the titration of the chloride ions with the silver nitrate solution, recording the volume (V) used 
to 0.05 ml.  
 
Carry out a blank titration under the same conditions and record the volume (V o) to 0.05 ml.  
 
4.2.3.  Method 2  
If the admixture does contain, or can b e assumed to contain lignosulphonate or reducing agents, the sample 
shall be diluted or dissolved and made up to 100 ml with distilled or demineralized water. Then add 5 ml of 
sodium hydroxide solution followed by 10 ml of hydrogen peroxide. This can cause  an exothermic reaction.  
 
In order to avoid loss of chloride ions, make sure that the pH remains above 8.5 by adding, if necessary, more 
sodium hydroxide solution. Bring the solution very slowly to the boiling point by means of a heating device with 
a magn etic stirrer and boil for 30 minutes1). 
 
Leave the solution to cool to (20 ± 2) °C. Then add 80 ml of acetone followed by dilute nitric acid until the pH is 
(2.0 ± 0 .5) and carry out the titration of the chloride ions using the silver nitrate solution, rec ording the volume 
used (V) to 0.05 ml. 
 
Carry out a blank titration under the same conditions and record the volume (V o) to 0.05 ml.  
 
4.2.4.   Method 3  
 
NOTE  Carry out this test in an extraction cabinet to minimise the risk from the exothermic reaction and the  escape of hydrogen cyanide. The 
operator should wear suitable protective clothing.  
 
If the admixture does contain, or can be assumed to contain thiocyanate, dissolve the sample if necessary 
and dilute to 100m1 using distilled or demineralised water then plac e the sample in a 500 ml beaker in order to 
avoid losses by overflow.  
 
Carefully add 5 ml of sodium hydroxide solution followed by 10 ml of hydrogen peroxide. This can cause an 
extremely exothermic reaction. After this reaction has subsided, add again 10 m l of hydrogen peroxide and 
repeat the addition three times. In order to avoid loss of chloride ions and minimise the escape of hydrogen 
cyanide, make sure that the pH remains above 8.5 at all times by adding, if necessary, more sodium 
hydroxide solution.  
 
Heat the solution slowly to the boiling point and keep it boiling for 2 h. leave  the solution to cool slowly to (20 + 2) 
°C. Then transfer the solution into a 250 ml beaker using distilled or demineralized water to wash out the 500 ml 
beaker.  
 
Add 80 ml of  acetone followed by dilute nitric acid until the pH is (2.0 ± 0.5) and carry out the titration of the 
chloride ions using the silver nitrate solution, recording the volume used (V) to 0.05 ml.  
 
Carry out a blank titration under the same conditions and rec ord the volume (V o) to 0.05 ml  
 
5.  Results  
The results shall be expressed in % by mass.  
 
                                                      
1 Some admixtures may foam while boiling. This may be reduced by the addition of ethanol.