ICS 91.080.30   
 
Reference number  
DRS  211-2: 2010 
© RSB 2021  
 l 
 RWANDA 
STANDARD  DRS  
211-2  
 
First edition  
2010-03-18 
(Reaffirmed 2021 -mm-dd) 
 
Mortar for masonry — Test method s —  
Part 2: Bulk sampling of mortars and 
preparation of test mortars  
   
DRS  211-2: 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  
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prior written permission from R SB. 
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ePortal: www.portal.rsb.gov.rw   DRS  211-2: 2010 
iii                ©RSB 2021  - All rights reserved  
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ ...................  iv 
1 Scope  ................................ ................................ ................................ ................................ .............  1 
2 Normative references  ................................ ................................ ................................ ...................  1 
3 Terms and definitions  ................................ ................................ ................................ ..................  1 
4 Minimum bulk test sample size  ................................ ................................ ................................ ... 2 
5 Preparation of the bulk test sample and individual test samples  ................................ ...........  2 
5.1 Apparatus  ................................ ................................ ................................ ................................ ...... 2 
5.2 Procedure  ................................ ................................ ................................ ................................ ...... 2 
5.2.1  Procedure  ................................ ................................ ................................ ................................ ...... 2 
5.2.2  Sampling from batch mixers  ................................ ................................ ................................ ....... 2 
5.2.3 Sampling from conveyors or pipelines  ................................ ................................ ......................  2 
5.2.4  Sampling from large hopers, beans, or heaps being moved  ................................ ...................  3 
5.2.5  Sampling from small hoppers, bins, static heaps, or bags  ................................ .....................  3 
5.2.6  Bulk transport vehicles  ................................ ................................ ................................ ................  3 
5.3 Reduction of the bulk sample  ................................ ................................ ................................ ..... 3 
5.4 Packing and certificate of sampling  ................................ ................................ ...........................  3 
5.5 Laboratory examination of bulk test samples  ................................ ................................ ...........  4 
5.6 Time of testing  ................................ ................................ ................................ ..............................  4 
6 Preparation of test mortars from dry constituents and water or pre -batched mixes and 
binders  ................................ ................................ ................................ ................................ ...........  4 
6.1 Amount of mortar for test samples  ................................ ................................ ............................  4 
6.2 Mixing the mortar  ................................ ................................ ................................ .........................  5 
6.2.1  General  ................................ ................................ ................................ ................................ ..........  5 
6.2.2  Mixer  ................................ ................................ ................................ ................................ ..............  5 
6.2.3  Pan mixer  ................................ ................................ ................................ ................................ ...... 6 
 DRS  211-2: 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  211-2 was prepared by Technical Committee RSB/TC 009, Civil engineering  and b uilding 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 m ethods : 
⎯ 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 adhe sive strength of hardened rendering and plastering mortars on substrates  
⎯ Part 7: Determination of water absorption coefficient due to capillary action of hardened mortar  
 
 
 DRS  211-2: 2010 
v                ©RSB 2021  - All rights reserved  
 Committee membership  
The following organizations were represented on the Technica l Committee on Civil engineering  and building 
materials  (RSB/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 Author ity (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  211-2: 2010 
1                ©RSB 2021  - All rights reserved  
 Mortar for masonry — Test method s — Part 2: Bulk sampling of mortars 
and preparation of test mortars   
1 Scope  
This Draft Rwanda Standard  provides methods for taking a bulk sample of fresh mortar, and the preparation of 
a bulk test sample from this.  
It also provides a procedure for producing test mortars from dry constituents and water.  
2 Normative references  
The f ollowing 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 doc ument (including any amendments) applies.  
RS EAS 148 -1, Cement  – Test methods – Part 1: Determination of strength  
RS 211-3, Mortar for masonry – Methods of test – Part 4: Determination of consistence of fresh mortar (by 
flow table)    
3 Terms and definitions  
For the purposes of this standard, the following terms and definitions apply.  
3.1 
lot  
quantity of mortar produced under conditions presumed uniform. After specified tests this quantity is regarded 
as a whole ‘’conforming’’ or ‘’not conformin g’’ to the specifications  
3.2 
increment  
quantity of mortar taken in a single operation of the sampling equipment used  
3.3   
bulk sample  
aggregation of sample increments meant to represent the lot sampled   
©RSB 2021  - All rights reserved                  2 
 3.4 
bulk test sample  
reduced sample taken from the bulk sample which is used for the testing purposes of this standard  
4 Minimum bulk test sample size  
The minimum bulk test sample size shall be 10 kg.  
5 Preparation of the bulk test sample and individual test samples  
5.1 Apparatus  
5.1.1  Metal or rigid plastics receptacle or scoop of not less than 1 L capacity.  
5.1.2  Clean, dry containers with close -fitting lids.   
5.1.3  Trowel or palette knife .  
5.1.4  Flat shovel.   
5.2 Procedure  
5.2.1  Procedure  
5.2.1.1  Obtain the bulk sample by taking uniformly di stributed increments (preferably from material in 
motion, provided this can be carried out in safety), and mix thoroughly.  
5.2.1.2   Reduce the bulk sample in accordance with 5.3 to obtain the bulk test sample.  
5.2.2  Sampling from batch mixers  
Sample the mortar  at the discharge point of a batch from the mixer. Take not less than three increments spaced 
evenly through the batch at the discharge point of the mixer. Take increments by passing the receptacle across 
the stream of mortar in such a manner as to collect  a representative sample of mortar.  
5.2.3  Sampling from conveyors or pipelines  
5.2.3.1  Sample the mortar at the discharge point of the conveyor or pipeline. Pass the receptacle across 
the stream of mortar, if possible,  so as to cross the whole of the stream un til it is filled. If it is not possible to 
catch the whole stream at once, pass the receptacle through the stream at a uniform rate so that consecutive 
increments are taken from different parts of the stream. Where it is not possible to sample at the disch arge point 
of the conveyor, stop the conveyor and use the scoop (see 5.1.1) to take increments from the full width and 
thickness of the stream of mortar on the conveyor.  DRS  211-2: 2010 
3                ©RSB 2021  - All rights reserved  
 5.2.3.2  Take not less than three increments at regularly spaced time intervals during  the passage of the 
whole of the quantity of the mortar that is being sampled.  
5.2.4  Sampling from large hopers, beans, or heaps being moved   
Sample the mortar when hoppers or bins , are being filled or emptied or when heaps are being moved, in 
accordance with 5 .2.3.  
5.2.5  Sampling from small hoppers, bins, static heaps, or bags  
Sample the mortar by means of the scoop. Take increments from material not less than 100 mm below 
the surface in at least three different places, distributed in a regular manner throughout the mass, so as 
to ensure, when mixed, a thoroughly representative combined sample.  
5.2.6  Bulk transport vehicles  
Sample the contents of bulk transport containers either during filing or emptying in accordance with 5.2.3 or, 
when this is not practical, by taking increments in accordance with 5.2.5.  
5.3 Reduction of the bulk samp le  
Immediately after collecting, using a flat shovel (see 5.1.4) combine and thoroughly mix the increments, taken 
in accordance with any of the methods described, on a flat, impervious rigid surface. Care should be taken when 
lightweight or fibrous compon ents are present in order to avoid segregation. Complete the mixing within 5 min 
of placing the increments upon the surface. Reduce the bulk sample to produce a bulk test sample of not less 
than 10 kg by taking sufficient scoopfuls from random positions th roughout the mixed material. Place the bulk 
test sample in one or more containers (see 5.1.2) with close -fitting lids. The sampling operation shall not take 
longer than 3 min.  
5.4 Packing and certificate of sampling  
5.4.1  Each bulk test sample to be dispatch ed to a laboratory in the containers shall be suitably labelled so 
that its origin can be identified at the laboratory. The bulk test sample shall be accompanied by a certificate from 
the person responsible for taking the samples stating that sampling was carried out in accordance with the 
requirements of this Rwanda Standard.  
5.4.2  This certificate shall include the following information:   
a) the name and address of the body responsible for sampling;  
b) the name and address of the customers;  
c) the place, date  and time and method of producing the bulk test sample;  
d) identification of the mortar sample, including type, origin and designation by reference to the relevant 
Standard.  
e) the quantity of the lot, or the period of production represented by the bulk sample ;  
f) the number of increments and the mass of the original bulk sample;   
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 g) age of mortar when sampled;  
h) identification mark on sample container; and  
i) remarks.  
5.4.3  In addition it is recommended that the following be added, if known:  mixing procedure, i.e. mi xer type 
and length of mixing period .  
5.5 Laboratory examination of bulk test samples   
5.5.1  Each bulk test sample received at the laboratory for test shall be examined visually to ascertain whether 
setting, leakage, or evaporation has occurred. If so, the b ulk test sample shall be rejected for further tests, other 
than sieve analysis (assuming the sample has not hardened). If none of the above factors is apparent, the whole 
of the sample, with any liquid that has separated, or has condensed on the inside of the container, shall be 
removed completely and mixed without loss of water to render it homogeneous.  
5.5.2  Where practicable, the temperature of the bulk test sample shall be adjusted to 20 °C + 5 °C, without 
loss of water. In all cases the temperature of  the sample at the time of test shall be recorded.  
5.6 Time of testing  
5.6.1  Bulk test samples dispatched to a laboratory for testing shall be tested immediately after arrival at the 
laboratory, and within the specified workable life of the mortar.   
5.6.2  Test ready to use mortars (plant -made wet mortars which are retarded), and pre-batched airlime/sand 
wet mortars when not gauged with hydraulic binders, within their specified workable life.  
6 Preparation of test mortars from dry constituents and water or pre -batched mixes 
and binders  
6.1  Amount of mortar for test samples  
The solid content of a prepared mortar mix, or the volume of the fresh mortar mix, shall be within the range 
given in Table 1.  
Table 1 – Solid content and volume of the mortar mix  
Fresh mortar mix  Mixer according to 
RS EAS 148 -1 Pan mixer  
Solid content (kg)  
Volume (dm3) 1.8 - 3.0 
0.5 - 2.5 30 - 50 
25 - 75 DRS  211-2: 2010 
5                ©RSB 2021  - All rights reserved  
 6.2 Mixing the mortar  
6.2.1  General  
6.2.1.1  Fresh mortar used for the purpose of testing and preparing specimens for tests shall, as far as 
possible, have the consistence appropriate for its use. Unless otherwise specified, bring the fresh mortar sample 
to a defined flow value as specified in Table 2, and determined in accordance with RS  211-3 the water 
determined by the use of trial mixes.  
Table 2 – Defined flow value for various types of mortar related  to the bulk density of fresh mortar  
Bulk density of fresh mortar 
kg/m 3  Flow value mm  
> 1200  
> 600 - < 1200  
> 300 - < 600  
< 300  175 + 10  
160 + 10  
140 + 10  
120 + 10  
6.2.1.2  Carry out mixing according to the mortar manufacturer’s instructions. If such instructions are not 
manufacturer’s instructions or if they are not available, follow the mixing procedure described in 6.2.2 or 6.2.3. 
Mix with the amount of water expected to g ive a mortar with the intended consistence.  
6.2.1.3  Measure the length of the mixing period from the moment all consistence.  
6.2.1.4  Measure the length of the mixing period from the moment all constituents are introduced into the 
mixer.  
6.2.1.5  Record a ny deviation from the mixing procedure prescribed.  
6.2.2  Mixer   
6.2.2.1  After the predetermined amount of water has been introduced into the mixer, add the solid content 
of the dry mortar mix, as given in Table 1, over a period of 30 s with the mixer running a t low speed.  
6.2.2.2  For lightweight mortars correspondingly reduce the amount and take from a vessel as an average 
sample. Then complete mixing at the same speed for a further 60 s unless otherwise specified by the 
manufacturer.  
NOTE   Some admixtures ma y not be activated within the specified time and particular attention should be paid to 
the manufacturer’s instructions.  
6.2.2.3  Follow the same procedure also for plant -made mortars to which only water is to be added.  
6.2.2.4  For pre -batched mortars to  which binders are also to be added, mix the additional proportion of 
binder into the water over a period of 15 s before adding the pre -batched constituents and with the mixer running 
at low speed. Then follow the same procedure as described above to compl ete mixing.   
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 6.2.3  Pan mixer  
Carry out the mixing process in the same way as described in 6.2.2, the solid content of the dry mortar mix, as 
given in Table 1, being added over a period of 15 s with the mixer running. Then complete the process by mixing 
for a fu rther 120 s - 180 s, the latter preferred for lightweight mortars and for high lime -based mortars.  
 
 DRS  211-2: 2010 
 
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