KENYA STANDARD      DKS 2802-11:2019 
ICS  
  
 
 
  
 
  
 
 
 
  
 
  
Masonry units — Methods of test  
 
Part 11:  
Determination of water absorption of clay and 
calcium silicate masonry units by cold-water 
absorption 
 
  
 
 
  
 
  
 
  
 
  
 
  
 
 
  
 
 
  
 
© KEBS 2019 First Edition, 2019 DKS 2802-11:2019  
ii  © KEBS 2019 — All rights reserved TECHNICAL COMMITTEE REPRESENTATION 
 
The following organizations were represented on the Technical C ommittee:  
 
National Housing Corporation 
Kenya Clay Products Ltd 
Coast Clay Works Ltd Consumer Information Network 
University of Nairobi  
Kenya Industrial Research & Development Institute 
Architectural Association of Kenya 
M&O Consulting Engineers 
Kenya Association of Manufacturers, 
Kenya National Federation of Jua Kali Association 
Lake Basin Development Authority 
Kenya Bureau of Standards — Secretariat 
 
 
 
 
 
    
 
 
 
  
 
 
 
  
 
REVISION OF KENYA STANDARDS 
 
In order to keep abreast of progress in industry, Kenya Standar ds shall be regularly reviewed. Suggestions for 
improvements to published standards, addressed to the Managing Director, Kenya Bureau of Standards, are 
welcome.  
 
  
© Kenya Bureau of Standards, 2017 
 Copyright. Users are reminded that by virtue of Section 25 of the Copyright Act, Cap. 130 of 2001 of the Laws of Kenya, copyrig ht subsists 
in all Kenya Standards and except as provided under Section 25 of this Act, no Kenya Standard produced by Kenya Bureau of Stand ards KENYA STANDARD                                       DKS 2802-11:2019 
ICS  
© KEBS 2019 — All ri ghts reserved   iii may be reproduced, stored in a retrieval system in any form or transmitted by any means without prior permission in writing fro m the 
Managing Director.   DKS 2802-11:2019  
iv  © KEBS 2019 — All rights reserved Masonry units — Methods of test  
 
Part 11: 
 
Determination of water absorption of clay and calcium 
silicate masonry units by cold water absorption 
 
 
  
 
  
 
  
 
  
 
  
 
  
 
 
  
 
  
 
  
 
 
  
 
  
 
KENYA BUREAU OF S TANDARDS (KEBS) 
 
Head Office: P.O. Box 54974, Nairobi-00200, Tel.: (+254 020) 605490, 602350,  Fax: (+254 020) 604031 
E-Mail: info@kebs.org, Web:http://www.kebs.org  
 
Coast Region    Lake Region    Rift Valley Region  
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Fax: (+254 041) 229448   Fax: (+254 057) 21814 
 
Foreword 
 KENYA STANDARD                                       DKS 2802-11:2019 
ICS  
© KEBS 2019 — All rights reserved   v This Kenya Standard was prepared by the Clay and Clay Products Technical Committee under the guidance 
of the Standards Projects Committe e and in accordance with the procedures of the Kenya Bureau of 
Standards. 
 
During the development of this standard, reference was made to the following documents: 
 
BS EN 772-21:2011 Methods of test for masonry units - Part 21: Determination of water absorption 
of clay and calcium silicate masonry units by cold water  absor ption. 
 
Acknowledgement is hereby made for the assistance received from  these sources. 
  
KENYA STANDARD        DKS 2802-11:2019 
 
 
© KEBS 2019 — All rights reserved   1  
Masonry units — Me thods of test  
 
Part 11:  
Determination of wate r absorption of clay and calcium silicate masonry 
units by cold - water absorption 
 
1. Scope  
 
This Kenyan Standard specifies a method of determining the wate r absorption of clay and calcium silicate 
masonry units by immersing them in cold water. 
 
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 refere nces, the latest edition of the referenced 
document (including any amendments) applies. 
 DKS 2801-1, Specification for masonry units -   Part 1: Clay ma sonry units 
 
EN 771-2, Specification for masonry units -   Part 2:  Calcium silicate masonry units 
 EN 771-3, Specification for masonry units -    Part 3: Aggregat e concrete masonry units (Dense and light• 
Weight aggregates) 
 EN 771-4, Specification for masonry units -   Part 4: Autoclave d aerated concrete masonry units 
 
EN 771-5, Specification for masonry units -   Part 5: Manufactu red stone masonry units 
 
EN 771-6, Specification for masonry units -   Part 6: Natural s tone masonry units 
 
3. Principle 
 
After drying to constant mass a masonry unit is immersed in wat er for 24 h and the increase in mass is 
determined. 
 
4. Symbols 
 
Md    is the mass of the specimen after drying (g);  
Ms    is the mass of the specimen after soaking (g);  
Ws       is the water absorption of the specimen (%). 
5. Apparatus 
 
5.1. Water tank large enough to contain all of the samples, supporte d off the base of the tank so that water 
is in contact with all the faces of the specimen. 
 
5.2. Ventilated oven capable of maint aining a temperature of 105 °C ± 5 °C. 
  
2  © KEBS 2019 — All rights reserved 5.3. Weighing instrument capable of weighing the specimens to an acc uracy of 0, 1 % of their mass when 
dry.  
 
6. Preparation 
 
6.1. Sampling 
 The method of sampling shall be in accordance with the relevant  part of DKS 2801. 
 The minimum number of specimens shall be six, but a larger mini mum number may be specified in the product 
specification, in which case that larger number shall be used. 
 
6.2. Drying 
 Dry the test specimens to constant mass M
d in a ventilated oven (5.2) at a temperature of 105 °C ± 5 °C. 
Constant mass is reached if, during the drying process in two s ubsequent weighings with not less than a 24 h 
interval, the loss in mass between the two determinations is no t more than 0,2 % of the total mass. Allow the 
specimens to cool to ambient temp erature before they are weighe d. 
 
7. Test procedure 
 
Place each unit in the tank of water.  
Leave clay units submerged for 24 h ±. 0,5 h. Leave calcium sil icate units submerged for 48 h ± 0,5 h. Take 
the units from the tank and remove any water from their surface s using a damp cloth or sponge. Weigh the 
specimens and record their mass, M5.  
8. Calculation of results 
 
Calculate the water absorption Ws of each of the units to the nearest 1 %. 
 
            
9. Evaluation of results 
 
Calculate the mean water absorption to the nearest 1 %. 
 
 
10. Test report 
 
The test report shall contain the following information:  
a) number,   title and date of issue of this Kenyan Standard; 
b) name of the organization that carried out the sampling and t he method used; 
c) date of testing; 
d) description of the specimens to DKS 2801-1 or EN 771-2 as is  relevant; 
e) number of specimens in the sample; 
f) mass  of each specimen  dry and after soaking; g) soaking period in hours; 
DKS 2802-10:2019  
© KEBS 2019 — All rights reserved   3 h) individual and mean water absorption values to the nearest 1  %; 
i) remarks, if any.