Reference number  
DRS 107: 2018  
© RSB 2018 
  
 RWANDA 
STANDARD  DRS 
107: 201 8 
 
Second  edition  
2018-xx-xx 
 
Building Sands  from natural sources  — 
Specification   
 
 DRS 107: 2018 
1                ©RSB 2018 - All rights reserved  
 In order to match with technological development and to keep continuous progress in industries, 
standards are subject to periodic revie w. Users shall ascertain that they are in possession of the latest 
edition  
 
 
 
 
 
 
 
 
© RSB 2018  
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   
e-Portal: www.portal.rsb.gov.rw    DRS 107: 201 8 
©RSB 2018 - All rights reserved                  2 
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ .............................. 3 
1 Scope  ................................ ................................ ................................ ................................ ...................... 5 
2 Normative references  ................................ ................................ ................................ ............................ 5 
3 Terms and definitions  ................................ ................................ ................................ ........................... 5 
4 Sampling  ................................ ................................ ................................ ................................ ................ 6 
5 Quality of sands  ................................ ................................ ................................ ................................ .....7 
6 Grading  ................................ ................................ ................................ ................................ ................... 8 
6.1 Grading for sands for external renderings and internal plastering with cement and lime  ............ 8 
6.2 Grading fo r sands for masonry mortar  ................................ ................................ ............................... 9 
7 Supplier's certificate and cost of tests  ................................ ................................ ................................ 9 
Annex  A ................................ ................................ ................................ ................................ ............................... 1 
Annex  B ................................ ................................ ................................ ................................ ............................... 2 
 DRS 107: 2018 
3                ©RSB 2018 - All rights reserved  
 Foreword   
Rwanda Standard s are prepared  by Technical Committees and approved by R wanda Standards Board (RSB) 
Board  of Directors in  accordance with the procedures of RSB, in compliance with Anne x 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 107 was prepared by Technical Committee RSB/TC 09, Civil Engineering and Building Materials . 
In the preparation of this standard, reference was made to the following standard  (s): 
1) BS  1199 and 1200 : Specification for building sands from natural sources  
The assistance de rived from the above source is hereby acknowledged with thanks.  
This second e dition  cancels and replaces the first edition (RS  107: 2010 Building Sands - Specification ), of 
which has been technically revised.  
Committee membership  
The following organizations were represented on the Technical Committee on Civil Engineering and Building 
Materials (RSB/TC 09) in the preparation of this standard.  
Green Effect Engineering  
Institut d’ Enseignement Supérieur ( INES - Ruhengeri ) 
NPD Ltd  
Ruliba Clays  
EarthEnable  
Rwanda Housing Authority  (RHA)  
Rwanda Transport Development Agency ( RTDA ) 
Standards for Sustainability  
Strawtec  
University Of Rwanda – College of Science & Technology  
Rwanda  Standards Board  (RSB) – Secretariat  
 DRS 107: 201 8 
©RSB 2018 - All rights reserved                  4 
 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 m ethod 
specified is considered to be more reproducible 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 bringin g the 
majority of sands in satisfactory use . Experience 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 greater 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: 2018 
5                ©RSB 2018 - All rights reserved  
 Building sands from natural sources — Specification  
1 Scope  
This Draft Rwanda Standard covers the r equirements for naturally occurring sands, crushed stone sand and 
crushed gravel sands 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 w ithout the addition of lime). It 
also relates to sands  intended to be used for mortar for masonry , for brickwork (plain and  reinforced) , for 
building with clay or concrete block  and for masonry.  
 
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 references, the latest edition of the referenced 
document (including any amendments) applies.  
RS 96 -3, Aggregates− Test Methods: Part 3 : Methods of s ampling  
RS 96 – 4, Determination of particle size distribution – sieve tests   
RS ISO 3310 -2, Test sieves —Part 2: Technical requirements and testing, Part 2: Test sieves and of metal 
wire cloth  
3 Terms and definitions  
For the purposes of this stand ard, the following 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 I SO sieve no. 200  and passing a 4.75mm 
RS (No. 4) sieve. It  may be either natural sand 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. 
3.3 
Coarse sand  
Granular m aterials passing a 4.75 -mm sieve (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 
medium sand is composed of particles between 0.60mm to 0.2mm.  DRS 107: 201 8 
©RSB 2018 - All rights reserved                  6 
 3.5 
Fine sand  
Granular m aterial s passing a 0.475 -mm (No. 40) sieve and retained on a 0.075 -mm (No. 200) sieve.  The 
fraction of fine san d is composed of particles between 0.20mm to 0.06mm.  
3.6 
Clean sands  
These are well -graded sands containing entirely or mostly quartz (SiO 2) particles in wide range of grain size.  
3.7 
Silty Sands  
These are poorly graded sands, which have considerable propo rtion of silt (particle size between (1/16 – 
1/256mm) and other non plastic -fines.  
3.8 
Clayey Sands  
These are poorly graded sands having a prominent clay fraction (particle size below 1/256 mm) and also 
plastic fines.  
3.9 
crushed stone sand and crushed gra vel 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.  
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 more 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.  
4 Sampling and Testing  
4.1 Guidelines for s ampling  and testing of sands shall be carried out in accordance with the requirements of 
RS 96  - 3 & 96  -2. 
4.2 Testing of sands shall be carried out in accordance with the requirements of relevant parts of RS 96.  
4.3 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 square hole perforated DRS 107: 2018 
7                ©RSB 2018 - All rights reserved  
 plate; 2.36 mm, 1.18 mm, 600 µm, 300 µm, 150µm, 75 µm woven wire as described in RS 96 -4 or RS ISO 
3310 -2 
4.4  When testing is carried out, compliance of the material with this Standard shall be judged using the 
average of two single test results obtained by testing different test portions  
5 Quality of sands  
5.1 General Requirements  
5.1.1  Sands shall consist of natural sand, manufactured sand, crushed stone sand or crushed gravel sand, or 
a combination of any of these. The san shall be hard, durable, clean and free from  impurities.  
5.1.2  The var ious sizes of particles of which sand is composed shall be uniformly distributed throughout 
the mass.  
5.1.3  Sands shall be chemically inert and not containing salts that can cause dampness  
Note:   Some variability in the measured properties of building sand s 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.  
5.2 Specific Requirements  
5.2.1  Deleterious m aterials  
Sands shall not contain harmful materials such as iro n 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 appearanc e 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 speci fied amount as described in 5.2.2  
5.2.2 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, the maximum quantities of 
clay, fine silt, fine dust and organi c impurities in the sand shall not exceed the following limit;  
a) clay, fin e silt and dust: Not more than 4%)by weight.  
b) organic impurities ;  the colour of liquid shall be below that indicated by comparison with the standard 
solution specified in Annex B of t his standard. Estimation of organic impurities shall be determined in 
accordance with RS ASTM C33 or Annex A of this standard.  
5.2.3  The average compressive strength, determined by the standard procedure of mor tar cubes with mix 
cement to sand mix ratio of  1:6, shall be not less than 3 N/mm2 at 28 days.  
 
 
 
 
 DRS 107: 201 8 
©RSB 2018 - All rights reserved                  8 
  
6 Grading  
6.1 Grading for sands for external renderings and internal plastering with cement and lime  
The sand shall be of type A or type B and graded within the limits given in Table 1, when determined 
according to clause 4.3.  
Table 1 – Sands for external renderings, internal cement and lime plastering  
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 
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 t he 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 generalized and auth oritative 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 other 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 jus t 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 depend, to s ome 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 finishes, s uch 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 coarser tha n 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.  DRS 107: 2018 
9                ©RSB 2018 - All rights reserved  
 6.2 Grading for 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 resu lt shall be greater than 10 % for uncrushed sands and 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 and reinf orced 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 
600 40 – 100 40 - 100 
300  5  –  70  20  -  90 
150 5  –   15    0 - 25 
75 
 
For crushed stone sands    0 – 5  
  
 0 – 10     0 – 8  
    
    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 th e 
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 before 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 representative.  
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:  
c) by the supplier, in the event of results showing that the material does not comply with the standard; and  
d) 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 information 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  DRS 107: 201 8 
©RSB 2018 - All rights reserved                  10 
 8.2 When request ed 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) Referenc e to this specification as DRS 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 determi ned according to the requirements of clause 4.3  
 DRS 107: 2018  
1                ©RSB 2018 - All rights reserved  
 Annex  A 
(normative ) 
 
Estimation of Organic Impurities  
 
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 b e harmful, and hence 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 percent solution of sodium hydroxide in water. The sand shall be added 
gradually until the volume measured by the sand layer is 125ml. The volume 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 hours.  
Other tests shall be made if the colour of the liquid above the sand is darker than a standard s olution freshly 
prepared as follows:  
Add 2.5 ml of 2 percent solution of tannic acid in 10 percent alcohol, to 97.5 ml of a 3 percent sodium 
hydroxide solution. Place in a 350 -ml bottle, stopper, shake vigorously and allow to stand for 24 hours before 
comp arison 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.  
 
 
 
 
 
 
 
 
 
 
  
©RSB 2018 - All rights reserved                  2 
 Annex  B 
(normative ) 
 
Determination of Clay. Fine silt and 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 testing 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 th e 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 an d 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 filli ng with 
distilled water; by reversing the tap, the water is run our into a bottle, weighed 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 accurate to 0.001 g.  
g) A well -ventilated oven, thermostatically controlled, to maintain a temperature of 1000C to 1100C. 
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 diluted 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 material. The amount of sample taken for test shall be in accordance 
with table B.1 . 
 
 
 DRS 107: 2018  
3                ©RSB 2018 - All rights reserved  
 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 
20 to 12.5  1 
10 to 6.3  0.5 
4.75 or smaller  0.3 
  
B.5 Test Procedure  
(Method of fine Aggregate )  
B.5.1  Approximately 300g of sample in the air dry condition, passing the 4. 74mm RS  or ISO Sieve s, 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 it s long axis, with this axis horizontal, at a speed of 80 +20 rev/min for a period of 15 minutes.  
B.5.2  At the end of 15 minutes, the suspension shall be poured into the 100 -ml measuring cylinder and the 
residue washed by gentle swirling and decantation of s uccessive 150 -ml portions of sodium oxalate solution, 
the washings being added to the cylinder until the volume is made up to 1 000ml. The determination shall be 
completed as described in B.5.3.  
B.5.3  The suspension in the measuring cylinder shall be thoro ughly 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 to 1100C to constant weight, cooled and weighed.  
B.5.4  Calculations  
The Propo rtion of the fine silt and clay or fine dust shall then 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  
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.5.5 Reporting Results   
©RSB 2018 - All rights reserved                  4 
 The clay, fine silt and fine dust content shall be reported to the nearest 0.1 percent.  
 
 
 DRS 107: 2018  
5                ©RSB 2018 - All rights reserved  
 Bibliography  
[1] SANS 1090:  2002:  Aggregates from natural sources —Fine aggregates for plaster and mortar  
[2] IS 2386: Methods of Tests for Agg regates, Part II: Estimation of deleterious materials and organic 
impurities  
[3] RS ISO 14688, Geotechnical Investigation and Testing  
[3] RS 96 -7, Methods of test for aggregates – Part 7 - Determination of moisture content  
 
 
 
 
 DRS 107: 2018  
ICS 91.100.15  
 
 
©RSB 2018 - All right s reserved