 
  
 ICS 91.100.15  
 
Reference number  
DRS 107: 20 23 
© RSB 20 23 
  
 RWANDA 
STANDARD  DRS 
107 
 
Third edition  
2023-mm-dd 
 
Building sand from natural sources — 
Specification  
 
   
DRS 107: 20 23 
©RSB 2023 - 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  
 
 
 
 
 
 
 
 
© RSB2023 
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized 
in any form or by any means, electronic or mechanical, including photocopying and microfilm, without 
prior written permission from R SB. 
Requests for permission to reproduce this document should be addressed to : 
Rwanda Standards  Board  
P.O Box 7099 Kigali -Rwanda  
KK 15 Rd, 49  
Tel. +250 788303492  
Toll Free: 3250  
E-mail: info@rsb.gov.rw  
Website: www.rsb.gov.rw  
ePortal: www.portal.rsb.gov.rw  DRS 107: 20 23 
iii                ©RSB2023- All rights reserved  
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ ............................  iv 
1 Scope  ................................ ................................ ................................ ................................ ......................  1 
2 Normative references  ................................ ................................ ................................ ............................  1 
3 Terms and definitions  ................................ ................................ ................................ ...........................  1 
4 Requirements  ................................ ................................ ................................ ................................ .........  3 
5 Sampling and testing  ................................ ................................ ................................ ............................  4 
6 Grading  ................................ ................................ ................................ ................................ ...................  4 
6.1 Grading for sands for external renderings, internal plastering and precast units with 
cement and lime  ................................ ................................ ................................ ................................ .... 4 
6.2 Grading for sands for masonry mortar  ................................ ................................ ...............................  5 
7 Supplier's certificate and cost of tests  ................................ ................................ ...............................  6 
8 Additional information to be furnished by the supplier  ................................ ................................ .... 6 
Annex  A (normative)  Estimation of Organic Impurities  ................................ ................................ ................  8 
A.1 A.1 General  ................................ ................................ ................................ ................................ .............  8 
Annex  B (normative)  Determination of Clay. Fine silt and Fine Dust (Sedimentation Method)  ................  9 
B.1 General  ................................ ................................ ................................ ................................ ...................  9 
B.2 Apparatus  ................................ ................................ ................................ ................................ ...............  9 
B.3 Chemicals  ................................ ................................ ................................ ................................ ...............  9 
B.4 Test Sample  ................................ ................................ ................................ ................................ ...........  9 
B.5 Test Procedure  ................................ ................................ ................................ ................................ .... 10 
B.5.1  Method of fine aggregate  ................................ ................................ ................................ ....................  10 
B.5.2  Calculations  ................................ ................................ ................................ ................................ .........  10 
B.5.3  Reporting results  ................................ ................................ ................................ ................................ . 11 
 DRS 107: 20 23 
©RSB 2023 - All rights reserved                  iv 
 Foreword  
Rwanda Standard sareprepared by Technical Committees and approved by R wanda 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 ratifie d by me mbers of RSB Board of Director s for publication and 
gazettment as Rwanda Standards.  
DRS107was prepared by Technical Committee RSB/TC 9,Civil engineering and building materials  
In the preparation of this standard, reference was made to the following standard:  
BS 1199 and 1200 : 1976, Specification for building sands from natural sources  
The assistance de rived from the above source is hereby acknowledged with thanks.  
This thirdedition cancels and replaces the second edition (RS  107: 201 8 Building sand from natural source s ― 
Specification), [clause 1  3and 6],which has been technically revised.  
Committee membership  
The following organizations were represented on the Technical Committee on Civil engineering and building 
materials (RSB/TC 9) in the preparation of this standard.  
Integrated Polytechnic Regional Centre (IPRC – Musanze)  
Rwanda Inspectorate, Competition and Consumer Protection Authority (RICA)  
Rwanda Transport Development Agency (RTDA)  
Saint Joseph Engineering Company (SJEC Ltd)  
SEG -Ltd 
University of Rwanda – College of Science and Technology  (UR - CST)  
Rwanda Standards Board (RSB) – Secretariat  DRS 107: 20 23 
v                ©RSB2023- All rights reserved  
 Introduction  
The method of determining the grading of sands is restricted to that of washing and decantation, followed by 
dry sieving, and the method of dry sieving only is no longer permitted. The washing and sieving method 
specified is considered to be more reproduc ible and to produce a more realistic measure of the particle size 
distribution of the sand.  
It also determines the clay and silt content which is now incorporated in the grading requirements. This 
change to washing and sieving necessitates revision of the grading limits as those previously given in this 
edition were based on results from dry sieving.  
This is not intended to lead to changes in the gradings of sand in use, but it will have the effect of bringing the 
majority of sands in satisfactory use. Expe rience currently available suggests that satisfactory renderings can 
be achieved using either grade. Where there is a choice, however, the use of the coarser grade is preferred 
because finer sands require a higher water to cement ratio which can lead to gr eater shrinkage than if a 
coarser grading is used.  
Some variability in the measured properties of building sands from any source has to be expected. This is 
caused by sampling and testing errors in addition to the natural variability of the material itself . The application 
of statistical methods has been considered, but has not been included at the present time.  
 DRS 107: 20 23 
1                ©RSB2023- All rights reserved  
 Building sand from natural sources — Specification  
1 Scope  
This Draft  Rwanda Standard specifies  requirements for naturally occurring sand, crushed stone sand and 
crushed gravel sand used for external renderings and internal plastering using mixes of lime and sand (with or 
without the addition of cement or gypsum plaster), cement and sand (with or wi thout the addition of lime).  
It applies to sand intended to be used in mortar for masonry, for brickwork (plain and reinforced), for building 
with clay or concrete block and for masonry.  
It also applies to sand intended for manufacturing precast units.  
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 editioncited applies. For undated references, 
the latest editio n of the referenced document (including any amendments) applies.  
DRS 96 -3, Aggregates — Test methods — Part 3: Sampling  methods  
DRS 96 – 4, Methods of test for aggregates — Part 4: Determination of particle size distribution — Sieve tests  
RS ISO 3310 - 2,Test sieves — Technical requirements and testing — Part 2: Test sieves of perforated metal 
plate  
3 Terms and definitions  
For the purposes of this standard, the follow ing terms and definitions apply.  
3.1 
sand  
naturally occurring granular material composed of finely divided rock and mineral particles  with a diameter of 
between 0.074 mm to 4.75 mm retained on a standard RS sieve or ISO sieve no. 200  and passing a -4.75mm 
RS (No. 4) sieve. It may be either natural s and or one obtained by crushing hard rocks or gravels  
3.2 
natural sand  
sand produced by the natural disintegration of rock which has been deposited by streams or glacial agencies 
or obtained from pits   
©RSB 2023 - All rights reserved                  2 
 3.3 
coarse sand  
granular materials passing a 4.75 -mm si eve (No. 4) and retained on a 2.00 -mm (No. 10) sieve. The fraction of 
coarse sand is composed of particles between 2.00mm to 0.6mm  
3.4 
medium sand  
granular materials passing a 2.00 -mm sieve (No. 10) and retained on a 0.475 -mm (No. 40). The fraction of 
medi um sand is composed of particles between 0.60mm to 0.2mm  
3.5 
fine sand  
granular materials passing a 0.475 -mm (No. 40) sieve and retained on a 0.075 -mm (No. 200) sieve. The 
fraction of fine sand is composed of particles between 0.20 mm to 0.06 mm  
3.6 
clean sands  
well-graded sands containing entirely or mostly quartz (SiO 2) particles in wide range of grain size  
3.7 
silty Sands  
poorly graded sands, which have considerable proportion of silt (particle size between (1/16 – 1/256mm) and 
other non-plastic -fines  
3.8 
clayey sand  
poorly graded sand having a prominent clay fraction (particle size below 1/256 mm) and also plastic fines  
3.9 
crushed stone sand and crushed gravel sand  
fine aggregate produced by crushing a hard stone or rock and a gravel respectively  
3.10 
fine aggregate  
aggregate of particle size such that at least 90 % of its mass passes a sieve that has square apertures of 
nominal size 4.75 mm and that no greater mass percentage than that permissible in terms of Table 1 is 
retained on a sieve that has square apertures of nominal size 75 μm.  DRS 107: 20 23 
3                ©RSB2023- All rights reserved  
 3.11 
mortar  
mixture of fine aggregate and one or more cementitious binders and water, and that is used for the bedding 
and jointing of masonry units  
3.12 
plaster  
mixture of fine aggregate and one or mo re cementitious binders and water, and that is applied to surfaces 
(interior or exterior) other than floors, as a protective coating or as a decorative coating, or as both.  
3.13 
precast units  
masonry or construction units (a  block or slab,etc.) that are ca sted in a place other than where it is to be 
installed in a structure  (of a building or section , pavement etc.) cast before being transported to the site of 
installation  
4 Requirements  
4.1 General requirements  
4.1.1 Building sand shall consist of natural sand, manufactured sand, crushed stone sand or crushed gravel 
sand, or a combination of any of these. The san d shall be hard, durable, clean and free from impurities.  
4.1.2 The various sizes of particles of which sand is composed shall be uniformly  distributed throughout 
the mass.  
4.1.3 Sands shall be chemically inert and not containing salts that can cause dampness  
NOTE  Some variability in the measured properties of building sands from any source should be expected. This is 
caused by sampling and t esting errors in addition to the natural variability of the material itself.  
4.2 Specific requirements  
4.2.1 Deleterious materials  
Building sand shall not contain harmful materials such as iron pyrites, salts, coal or other organic impurities 
such as mica, shale or similar laminated materials, or flaky or elongated particles in such a form or in sufficient 
quantity to affect adversely  the hardening, the strength, the durability or the appearance of the final product or 
any materials in contact with it.  
Sands shall be free from adherent coatings and organic matter and shall not contain clay, silt and dust more 
than a specified amount a s described in 4.2.2  
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 4.2.2 Limits of deleterious materials  
Unless found satisfactory, as a result of further tests as may be specified by the engineer in charge of work, or 
unless evidence of such performance is offered which is satisfactory to him/her, th e maximum quantities of 
clay, fine silt, fine dust and organic impurities in the sand shall not exceed the following limit s: 
a) clay, fine silt and dust: Not more than 4 %)by weight ; and  
b) organic  impurities , the colour of liquid shall be below that indicated b y comparison with the standard 
solution specified in Annex B of this standard. Estimation of organic impurities shall be determined in 
accordance with RS ASTM C33 or Annex A of this standard.  
4.2.3 The average compressive strength, determined by the standard procedure of mortar cubes with mix 
cement to sand mix ratio of 1:6, shall be not less than 3 N/mm2 at 28 days.  
5 Sampling and testing  
5.1 Sampling and testing of sands shall be carried out in accordance with DRS 96-2&DRS 96 -3 
5.2 Testing of sands sh all be carried out in accordance with relevant parts of DRS 96.  
5.3 The grading of sands shall be determined by the method of sieve analysis by washing and decantation 
followed by dry sieving using the following nominal aperture size test sieves: 4.75 mm s quare hole perforated 
plate; 2.36 mm, 1.18 mm, 600 µm, 300 µm, 150 µm, 75 µm woven wire as described in RS ISO 3310 -2 
5.4 When testing is carried out, compliance of the material with this Standard shall be judged using the 
average of two single test result s obtained by testing different test portions  
6 Grading  
6.1 Grading for sands for external renderings , internal  plastering  and precast units  with 
cement and lime  
The sand shall be of type A or type B and graded within the limits given in Table 1, when deter mined 
according to clause 4.3.  
Table 1 – Sands for external renderings, internal cement and lime plastering  and for precast units  
RS sieve  Percentage by mass passing RS sieves  
Type A  Type B  
mm, %  
6.30 100 100 
4.75 95 - 100 95 - 100 
2.36 60 – 100 80 – 100 
1.18 30 – 100 70 – 100 
µm DRS 107: 20 23 
5                ©RSB2023- All rights reserved  
 600 15 – 80 55 - 100 
300 5 – 50 5 - 75 
150 5 – 35  
75 Not greater than 5  Not greater than 5  
 
6.1.1  Sands complying with the grading requirements in Table 1 for sieve apertures in the range 4.75 mm to 
600 µm but exceeding the requirements for the percentage passing the 300 µm, 150 µm and 75 µm sieves 
shall also be considered as being satisfactory where there is evidence of acceptable performance in use. 
Although insufficient information exists to provide generaliz ed and authoritative guidance on the use of such 
materials, local experience of their performance in use should help in the evaluation of their suitability for 
particular applications.  
6.1.2  A sand whose grading falls outside the above limits on sieves oth er than the 4.75 mm sieve in Table 1 
by a total amount not exceeding 5% shall be regarded as being within those limits. This 5% can be split up, for 
example, as 1% on each of three sieves and 2% on another, or 4% on one sieve and 1% on another.  
6.1.3  Sands  which just fall outside the above limits due to a small excess of coarse particles can often be 
made to comply with this Rwanda Standard by screening through a suitably sized sieve.  
NOTE  The most suitable grading of sand for an external rendering will dep end, to some extent, upon the finishing. 
The sand grading will, in general, be suitable for the undercoats and for some finishing coats such as the smooth (floated) 
finishing coats, the scraped finishes and for pebble -dash or dry -dash. For some textured fi nishes, such as those produced 
by treatment of the freshly applied final coat with a tool, it may be desirable to remove the coarser particles (e.g. by 
screening through a 2 -mm sieve), while for others such as “torn texture”, some proportion of material co arser than 5 mm 
may be needed. For roughcast (wet dashing or hurling) the grading and maximum size, will vary according to the texture 
required and the type of aggregate: the proportion of coarse material (over 5 mm) to fine should be about 1: 2.  
6.2 Grading f or sands for masonry mortar  
The grading of the sand when determined according to clause 4.3 shall be within the limits given in Table 2. 
Appropriate to its type. Additionally, for the upper limit for the percentage by mass sand passing the 75 µm 
sieve, no test result shall be greater than 10 % for uncrushed sands an d 15 % for crushed stone sands and 
not more than 1 in 10 consecutive results shall be greater than 8 % for uncrushed sands and 12 % for crushed 
stone sands.  
Table 2 — Sands for mortar for plain a nd reinforced brickwork, block -walling and masonry  
RS sieve  Percentage by mass passing RS sieves  
Type A  Type B  
mm, %  
6.30 100 100 
4.75 98 - 100 98 - 100 
2.36 90 – 100 90 – 100 
1.18 70 – 100 70 – 100 
µm  
©RSB 2023 - All rights reserved                  6 
 600 40 – 100 40 - 100 
300 5 – 70 20 - 90 
150 5 – 15 0 - 25 
75 0 – 5 0 – 8 
For crushed stone sands  0 – 10  0 – 12 
 
7 Supplier's certificate and cost of tests  
7.1 The supplier shall ensure that the output at the source of production complies consistently with the 
requirements of this Rwanda Standard and, if requested, shall give a certificate to this effect to the purchaser 
or his representative.  
7.2 If the purchaser or his representative requires independent tests or the certification of individual 
consignments, the samples shall be taken be fore or immediately after delivery at the option of the purchaser 
or his representative, and these tests shall be carried out in accordance with the appropriate requirements of 
this Standard on the written instructions of the purchaser or his representativ e. 
7.3 Unless otherwise specified with the enquiry and order, the supplier shall supply free of charge the 
material required for testing and the cost of the tests (unless otherwise stipulated) shall be borne:  
a) by the supplier, in the event of results showin g that the material does not comply with the standard; and  
b) by the purchaser, in the event of results showing that the material does so comply.  
8 Additional information  to be furnished by the supplier  
8.1 The direct purchaser of sand shall include the inform ation in 8.2 of this standard  in the purchase order 
as applicable. A project specifier shall include in the project documents information to describe the type of 
sand to be used in the project as stated in 8.2  
8.2 When requested by the purchaser or his/her  representative, the supplier shall provide any of the 
following additional particulars:  
a) source of supply (for material dredged from rivers, the precise locality from which the  material was 
obtained shall be  stated.)  
b) reference to this specification as RS 107  
c) the Quantity in cubic meters  
d) physical properties: the relative density and water absorption determined according to RS 96, and the 
bulk density in kilograms per cubic metre  
e) grading; a typical sieve analysis determined according to the requirements of clause 4.3  
 DRS 107: 20 23 
7                ©RSB2023- All rights reserved  
   
©RSB 2023 - All rights reserved                  8 
 Annex  A 
(normative ) 
 
Estimation of Organic Impurities  
A.1 A.1 General  
This method of test covers an approximate method of estimating whether organic compounds are present in 
natural sand in sufficient quantities to be harmful, and hen ce intended to show whether further tests are 
necessary or desirable.  
Note: Harmless organic materials may cause colouration and certain naturally occurring organic compounds do not cause 
colouration.  
Procedure  
The sand shall be tested as delivered and without drying. A 350 -ml graduated clear glass medicine bottle shall 
be filled to the 75 -ml mark with 3 % solution of sodium hydroxide in water. The sand shall be added gradually 
until the volume measured by the sand layer is 125 ml. The volu me shall then be made up to 200 ml by 
adding more solution. The bottle shall be stoppered and shaken vigorously and then allowed to stand for 24 h.  
Other tests shall be made if the colour of the liquid above the sand is darker than a standard solution fres hly 
prepared as follows:  
Add 2.5 ml of 2 % solution of tannic acid in 10 % alcohol, to 97.5 ml of a 3 -% sodium hydroxide solution. Place 
in a 350 -ml bottle, stopper, shake vigorously and allow to stand for 24 h before comparison with the solution 
above the  sand. Alternatively, an instrument or coloured acetate sheets for making the comparison can be 
obtained, but it is desirable that these should be derived on receipt by comparison with the standard solution.  DRS 107: 20 23 
9                ©RSB2023- All rights reserved  
 Annex  B 
(normative)  
 
Determination of Clay. Fine silt a nd Fine Dust (Sedimentation Method)  
B.1 General  
This is a gravimetric method for determining the clay, fine silt and fine dust, which includes particles up to 20 
micron. Differences in the nature and density of materials or in the temperature at the time of te sting may vary 
the separation point.  
B.2 Apparatus  
The apparatus shall consist of the following:  
a) A weight screw -topped glass jar of dimensions similar to a 1 -kg fruit preserving jar ; 
b) A device for rotating the jar about its long axis with this axis horizontal, at a speed of 80 +20 rev/min ; 
c) A sedimentation pipette of the Andreason type or its equivalent of approximately 25 ml capacity. This 
consists mainly of a pipette fitted with at the top with a two -way tap and held rigidly in a clamp which 
can be raised or lowered as required, and which is fitted with a scale from which the changes in height 
of the pipette can be read.  
The Volume of the pipette, including the connecting bore of the tap B is determined by filling with 
distilled water; by reversing the tap, th e water is run our into a bottle, we ighed and the volume 
calculated;  
d) A 1000 – ml measuring cylinder ; 
e) A scale or balance of capacity not less than 10 kg, readable and accurate to one gram ; 
f) A scale of balance of capacity not less than 250 g, readable and acc urate to 0.001 g ; and  
g) A well -ventilated oven, thermostatically controlled, to maintain a temperature of 100°C to 110°C. 
B.3 Chemicals  
A solution containing 8 g of sodium oxlate per litre of distilled water shall be taken. For use, this stock solution 
is dilute d with distilled water to one tenth (that is 100 ml diluted with distilled water to one litre.)  
B.4 Test Sample  
The sample for test shall be prepared from the main sample taking particular care that the test sample 
contains a correct proportion of the finer ma terial. The amount of sample taken for test shall be in accordance 
with table B.1.  
Table B 1 — Weight of sample for determination of Clay Fine Silt and Fine Dust  
Maximum size present in Substantial 
Proportions (mm)  Approximate Weight of sample for 
Test (kg ) 
63 to 25  6  
©RSB 2023 - All rights reserved                  10 
 20 to 12.5  1 
10 to 6.3  0.5 
4.75 or smaller  0.3 
B.5 Test Procedure  
B.5.1  Method of fine aggregate  
B.5.1.1  Approximately 300 g of sample in the air dry condition, passing the 4.74 mm ISO Sieves, shall be 
weighed and placed in the screw -topped glass jar, together with 300 ml of the diluted sodium oxalate solution. 
The rubber washer and cap shall be fixed, care being taken to endure water tightness. The jar shall then be 
rotated about its long axis, with this axis horizontal, at a sp eed of 80 +20 rev/min for a period of 15 min.  
B.5.1.2  At the end of 15 min, the suspension shall be poured into the 100 -ml measuring cylinder and the 
residue washed by gentle swirling and decantation of successive 150 -ml portions of sodium oxalate solution,  
the washings being added to the cylinder until the volume is made up to 1 000 ml. The determination shall be 
completed as described in B.5.3.  
B.5.1.3  The suspension in the measuring cylinder shall be thoroughly mixed by inversion and the tube and 
contents  immediately placed in position under the pipette. The pipette A shall then be gently lowered until the 
tip touches the surface of the liquid, and then lowered a further 10 cm into the liquid. Three minutes after 
placing the tube in position. The pipette A  and bore of tap B shall be filled by opening B and applying gentle 
suction at C. A small surplus may be drawn to run away and any solid matter shall be removed from the 
measuring cylinder and its contents run into a weighed container, any adherent solids being washed into the 
container by distilled water from E through the tap B.  
The contents of the container shall be dried at 100 °C to 110 °C to constant weight, cooled and weighed.  
B.5.2  Calculations  
The Proportion of the fine silt and clay or fine dust shall t hen be calculated from the following formula;  
Percentage of clay and fine silt or fine dust   
 
where 
W1 = weight in g of the original sample ; 
W2 = weight in g of the dried residue ; 
V = Volume in ml of the pipette ; and 
0.8 = weight in g of sodium oxalate in one litre of the diluted solution . DRS 107: 20 23 
11                ©RSB2023- All rights reserved  
 Note  No correction is made for water soluble salts which may be present in the sand, since the amount of such 
salts should be small.  
B.5.3  Reporting results  
The clay, fine silt and fine dust content shall be reported to the nearest 0.1 %.   
©RSB 2023 - All rights reserved                  12 
 Bibliography  
[1] SANS 1090: 2002, Aggregates from natural sources — Fine aggregates for plaster and mortar  
[2] IS 2386 ,Methods of Tests for Aggregates, Part II: Estimation of deleterious materials and organic 
impurities  
[3] RS ISO 14688, Geotechnical Investigation and Testing  
[4] RS 96 -7, Methods of test for aggregates — Part 7: Determination of moisture content  
 RS 207: 20 23 
 
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