ICS 91.080.30   
 
Reference number  
DRS  211-1: 2010 
© RSB 2021  
  
 RWANDA 
STANDARD  DRS 
211-1  
 
First edition  
2010 -03-18 
(Reaffirmed 2021 -mm-dd) 
Mortar for masonry — Test method s —  
Part 1: Determination of particle size 
distribution (by sieve analysis)  
   
DRS  211-1: 2010 
©RSB 2021  - All rights reserved                  ii 
 In order to match with technological development and to keep continuous progress in industries, 
standards are subject to periodic review. Users shall ascertain that they are in possession of the latest 
edition  
 
 
 
 
 
 
 
 
© RSB 2021  
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized 
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ePortal: www.portal.rsb.gov.rw   DRS  211-1: 2010 
iii                ©RSB 2021  - All rights reserved  
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ ...................  iv 
1 Scope  ................................ ................................ ................................ ................................ .............  1 
2 Normative references  ................................ ................................ ................................ ...................  1 
3 Terms and definitions  ................................ ................................ ................................ ..................  1 
4 Principle  ................................ ................................ ................................ ................................ ........  1 
5 Apparatus  ................................ ................................ ................................ ................................ ...... 1 
6 Preparation and storage of test samples from the bulk test sample.  ................................ ..... 2 
7 Procedure  ................................ ................................ ................................ ................................ ...... 3 
7.1 General  ................................ ................................ ................................ ................................ ..........  3 
7.2 Wet sieving  ................................ ................................ ................................ ................................ .... 3 
7.3 Dry sieving  ................................ ................................ ................................ ................................ .... 3 
7.4 Weighing  ................................ ................................ ................................ ................................ ....... 3 
8 Calculation and expression of results  ................................ ................................ .......................  4 
9 Test report  ................................ ................................ ................................ ................................ ..... 4 
 DRS  211-1: 2010 
©RSB 2021  - All rights reserved                  iv 
 Foreword  
Rwanda Standard s are prepared  by Technical Committees and approved by Rwanda Standards Board (RSB) 
Board  of Directors in  accordance with the procedures of RSB, in compliance with Annex 3 of the WTO/TBT 
agreement on the preparation, adoption and application of standards.  
The main task of technical committees is to prepare national standards.  Final Draft Rwanda S tandards adopted 
by Technical committ ees are ratified  by me mbers of RSB Board of Director s for publication and gazettment as 
Rwanda Standards.  
DRS  211-1 was prepared by Technical Committee RSB/TC 009, Civil engineering and building materials . 
In the preparation of this standard, reference was made to the following standard s: 
1) BS EN 998 -1, Specification for mortar for masonry – Part 1: Rendering and plastering mortar with inorganic 
binding agents   
2) BS EN 998 -2, Specification for mortar for masonry – Part 2: Masonry mortar   
3) BS EN 1015 -2, Methods of test for mortar for masonry – Part 2: Bulk sampling of mortars and preparation 
of test mortars  
The assistance de rived from the above source is hereby acknowledged with thanks.  
DRS  211 consists of the following parts, under the general title Mortar for masonry  —Test methods : 
⎯ Part 1: Determination of particle size distribution (by sieve analysis)  
⎯ Part 2: Bulk sampling of mortars and preparation of test mortars  
⎯ Part 3: Determination of consistence of fresh mortar (by flow table)  
⎯ Part 4: Determination of consistence of fresh mortar (by plunger penetration)  
⎯ Part 5: Determination of flexural and compressive strength of hardened mortar  
⎯ Part 6: Determination of adhesive strength of hardened rendering and plastering mortars on substrates  
⎯ Part 7: Determination of water absorption coefficient due to capillary action of hardened mortar  
 
 
 DRS  211-1: 2010 
v                ©RSB 2021  - All rights reserved  
 Committee membership  
The following organizations were represented on the Technical Committee on Civil engineering and building 
materials  (RBS/TC 009)  in the preparation of this standard.  
CIMERWA   
Enabel   
EGC Ltd   
GECO Africa  
Mass Design Group  
Rwanda Housing Authority (RHA)  
Rwanda Inspectorate, Competition and Consumer Protection Authority (RICA)  
Standard Geotechnical Engineering and Construction Ltd (STAGECO Ltd)  
SJEC Ltd  
University of Rwanda/College of Science and Technology (UR -CST)  
Rwanda  Standards Board  (RSB) – Secretariat  
  DRS  211-1: 2010 
1                ©RSB 2021  - All rights reserved  
 Mortar for masonry — Test method s — Part 1: Determination of particle 
size distribution (by sieve analysis)  
1 Scope  
This Draft Rwanda Standard  provides  two methods of determining the particle size distribution of dry mixed or 
nonhardened wet mixed mortars :  
a) wet sieving which is applicable to mortars containing normal weight aggregates ; and  
b) dry sieving which is applicable to mortars containing lightweight aggregates.  
2 Normative references  
The following documents are referred to in the text in such a way that some or all of their content constitutes 
requirements of this document.  For dated references, only the edition cited applies. For undated references, the 
latest edition of the referenced document (including any amendments) applies.  
RS 108, Mortar for masonry — Specification    
RS 211 -2, Mortar for masonry — Methods of test — Part 2: Bulk sampling of mortars and preparation of test 
mortars  
3 Terms and definitions  
No terms and definitions are listed in this document . 
4 Principle  
A series of test sieves (see 5.2) with increasing apert ure size are nested on top on one another on a bottom 
pan. The sample is placed on the top sieve and the stack of sieves is then agitated until further agitation causes 
no change in the mass retained on each sieve, which is weighed.  
NOTE   For samples with  particles of different densities the sieve analysis only gives  the particle size distribution in percentage 
of total mass.  
5 Apparatus  
5.1  Weighing instrument , with a capacity of 1 kg capable of weighing to an accuracy of 0.1 g.  
5.2  Test sieves , with square apertures, conforming to Table 1.  
NOTE   For aperture sizes of 4.00 mm and above perforated plate sieves are recommended.   
©RSB 2021  - All rights reserved                  2 
 Table 1 — Test sieves aperture sizes  
Aperture sizes mm  
4.75  
4.00  
2.00  
1.00  
0.500  
0.250  
0.125  
0.063  
5.3  Mechanical sieve shaker  
5.4  Well-fitting  pan and lid , for the sieves  
5.5  Shallow trays , made of corrosion -resistant metal, height  
5.6 Containers, suitable  for holding fresh mortar samples to which water can be added for the creation of a 
suspension  
5.7 A ventilated oven , capable of maintaining temperature of 105 °C + 5 °C and 60 °C + 5 °C respectively  
6 Preparation and storage of test samples from the bulk test sample.  
6.1 The bulk test taken in accordance with RS 211 -2 shall be reduced using a sample divider or by quartering, 
and shall yield a test sample of mass larger than the minimum, but not of an exact predetermined value. The 
minimum dray mass of the  test sample shall be as follows:  
⎯ 0.2 kg for d max < 4 mm; and  
⎯ 0.6 kg for d max > 4 mm.  
6.2 Mortars containing particles passing aperture size 0.125 mm may be wetted before reduction to minimize 
segregation and loss of dust. If the sample contains hydraulic binders, the following preparation under wet 
conditions shall be executed as quickly as possible. If dry sieving is required, the wetting of mortars containing 
hydraulic binders shall be omitted.   DRS  211-1: 2010 
3                ©RSB 2021  - All rights reserved  
 7 Procedure  
7.1 General  
Mortars shall be tes ted by dry sieving unless it is anticipated that may contain agglomerates when wet sieving 
shall be used.  
NOTE   Mortars containing lightweight or organic aggregates may become statically charged by the motion of the 
material on the sieve, resulting in agg lomeration, or sticking to the sieve base. Should such a phenomenon occur, suitable 
measures should be taken.   
7.2 Wet sieving  
Place the test sample in a container (see 4.6) and cover it with water. Mix the suspension up quickly, and pour 
it with the wash water on the nested sieves (see 5.2). Carry out sieving with the aid of a water jet until the wash 
water remains clean. Remove the fraction retained on each sieve and from the pan and spread each fraction in 
a thin layer into separate shallow trays (see 5.5). Dry each in the oven at a temperature of 105 °C + 5 °C. 
Continue the drying process until two consecutive weighing of each fraction at 2 h intervals do not differ by more 
than 0.2 g.   
7.3 Dry sieving  
Spread the  sample in a thin layer in shallow trays (see 5.5) and -dry in the oven (see 5.7) at a temperature of 
105 °C + 5 °C. For samples with organic constituents, e.g. expanded pol ystyrene aggregate or exfoliated 
vermiculite, use a drying temperature of 60 °C + 5 °C. Continue the drying process until two consecutive weithing 
of the sample at 2 h intervals do not differ by more than 0.2 % of the total sample mass will pass any indivi dual 
sieve during continuous hand for 1 min. Do not force any material through the sieve.   
7.4 Weighing  
74.1 Determine the mass of each fraction (m r) retained on the individual sieves and sum them to give the mass 
of the total sample. The difference between t he total and the sample weight is the amount of fine particles. On 
sieves with apertures smaller than 4.00 mm, the mass of each fraction retained at the end of the sieving 
operation shall not exceed:  
𝑚𝑟=A√𝑑
200 
where  
𝑚𝑟 is the mass of the fraction ret ained on the sieve (g);  
  A is the area of the sieve (mm2); and  
  d is the nominal aperture size of the sieve (mm);  
7.4.2  If any of the mass fractions retained exceeds this amount, use one of the two following procedures:   
©RSB 2021  - All rights reserved                  4 
 a) divide the fraction into portions smaller than the specified maximum and sieve these one after the 
other ; or  
b) divide the portion of the sample passing the 4.00 mm sieve with the aid of a sample divider or by 
quartering, and continue the sieve analysis on the reduce sample.  
8 Calculation and expression of results  
Calculate the individual fractions, as percentages of the total mass of the sample, and calculate the total 
percentage of material passing each sieve. If a dividing operation as described in 6.4 was performed, 
take this into account in the calculation.  
9 Test report  
The test report shall include the following information:  
a) place, date and time of taking the bulk test sample;  
b) method used for taking the bulk test sample (if known) ; 
c) name of the organization that took it ; 
d) date and time of testing;  
d) type, origi n and designation of the mortar by reference to RS 108;  
e) total mass of each individual test sample;  
f) method of sieving (dry or wet);  
g) percentage of the mass of the total sample passing each of the sieves, to the nearest 1 % ; 
h) a graphical presentation of the  results; and  
i) remarks, if any.   
NOTE  1  This information is contained in the certificate of sampling (see RS 211 -2)  
NOTE  2  This is the sample taken from the bulk supply that is to be used for all of the tests  in RS 211.  
 
 DRS  211-1: 2010 
 
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