ICS 93.080.30  
 
Reference number  
DRS 292: 2023  
© RSB 2023  
  
 RWANDA 
STANDARD  DRS  
292  
 
Second edition  
2023-mm-dd 
 
Aggregates for surface treatment of roads 
— Specification  
 
   
DRS 292: 2023  
©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 
 
 
 
 
 
 
 
 
© RSB 2023 
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 292: 2023 
iii                ©RSB 2023 - All rights reserved  
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ ...................  iv 
1 Scope  ................................ ................................ ................................ ................................ .............  1 
2 Normative references  ................................ ................................ ................................ ...................  1 
3 Terms and definitions  ................................ ................................ ................................ ..................  1 
4 Geometrical requirements  ................................ ................................ ................................ ...........  3 
4.1 General  ................................ ................................ ................................ ................................ ..........  3 
4.2 Selection of aggregates  ................................ ................................ ................................ ...............  3 
4.3 Sizes and grading of aggregates  ................................ ................................ ................................  4 
4.3.1  General  ................................ ................................ ................................ ................................ ..........  4 
4.3.2  Single -sized coarse aggregates  ................................ ................................ ................................ .. 4 
4.3.3  Fine aggregates  ................................ ................................ ................................ ............................  4 
5 Aggregate for slurry seal  ................................ ................................ ................................ .............  4 
6 Physical requirements  ................................ ................................ ................................ .................  5 
6.1 General  ................................ ................................ ................................ ................................ ..........  5 
The flakiness index  ................................ ................................ ................................ ................................ ... 6 
6.2 Water absorption  ................................ ................................ ................................ ..........................  6 
6.3 Density  ................................ ................................ ................................ ................................ ...........  6 
6.4 Soundness  ................................ ................................ ................................ ................................ .... 6 
6.5 Flakiness index  ................................ ................................ ................................ .............................  7 
The flakiness index of the coarse aggregates, when tested in accordance with the method given 
in RS 96 -5, shall not be more t han 15 %.  ................................ ................................ ...................  7 
6.6 Deleterious substances  ................................ ................................ ................................ ...............  7 
7 Mechanical properties ................................ ................................ ................................ ..................  7 
7.1 Aggregate crushing value  ................................ ................................ ................................ ...........  7 
7.2 Ten percent fines value ................................ ................................ ................................ ................  7 
7.3 Aggregate impact value  ................................ ................................ ................................ ...............  7 
7.4 Aggregate abrasion value  ................................ ................................ ................................ ...........  7 
8 Sampling and testing  ................................ ................................ ................................ ...................  8 
8.1 Sampling  ................................ ................................ ................................ ................................ ....... 8 
8.2 Testing  ................................ ................................ ................................ ................................ ...........  8 
9 Supplier’s certificate  ................................ ................................ ................................ ....................  8 
 DRS 292: 2023  
©RSB 2023 - 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 o f 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 292 was prepared by Technical Committee RSB/TC 55, Roads and highway  engineering  
In the preparation of this standard, reference was made to the following standard s: 
1) ASTM D1139/D1139M – 22, Standard Specification for Aggregate for Single or Multiple Bituminou s Surface 
Treatments  
2) SANS 1200M:1996 , Standards specification for civil engineering construction – Road (General)  
3) SANS 1200 MG:1996 , Standards specification for civil engineering construction – MG: Bituminous surface 
treatment  
4) ASTM D8 – 22, Standard Termin ology Relating to Materials for Roads and Pavements  
5) ASTM D75/D75M – 19, Standard Practice for Sampling Aggregates  
6) RS ASTM C131/C131M -20, Standard Test Method for Resistance to Degradation of Small -Size Coarse 
Aggregate by Abrasion and Impact in the Los Ang eles Machine  
7) ASTM C535 – 16, Standard Test Method for Resistance to Degradation of Large -Size Coarse Aggregate 
by Abrasion and Impact in the Los Angeles Machine  
The assistance de rived from the above source is hereby acknowledged with thanks.  
This second edition cancels and replaces t he first edition (RS  292: 2016 ), [clauses 1 , 3, 6 and 7 ] which has 
been technically revised.  
Committee membership  
The following organizations were represented on the Technical Committee on Roads and highway engineering  
(RSB/TC 55) in the preparation of thi s standard.  
ASTRIK International Ltd  
EDITRACE LTD and General Reliance  
JV CSC&EC(Property) and Fair Construction Ltd  DRS 292: 2023 
v                ©RSB 2023 - All rights reserved  
 MININFRA  
NPD Ltd  
Rwanda Inspectorate Competition and Consumer Protection Authority  (RICA ) 
Rwanda Transport Development Agency (RTDA)  
TCMF Ltd  
University of Rwanda - College of Science Technology (UR -CST)  
Rwanda Standards Board (RSB) – Secretariat  
  DRS 292: 2023  
1                ©RSB 2023 - All rights reserved  
 Aggregates for surface treatment of roads — Specification  
1 Scope  
This Draft Rwanda Standard covers requirements , sampling and test methods for crushed aggregates for  use 
in surface treatments in the construction , rehabilitation  or maintenance of bituminous roads surfacing. 
Requirements are laid down for sizes, strength, gradation of aggregates and methods of sampling and test.  
It is applicable t o common rocks and minerals suitable for use in the form of crushed stone for surface treatments 
of roads.  
2 Normative references   
The following referenced documents are indispensable for the application of this document. For dated 
references, only the editi on cited applies. For undated references, the latest edition of the referenced document 
(including any amendments) applies.  
RS ISO 565, Test sieves  —  Metal wire clo th, perforated metal plate and electroformed sheet —  Nominal sizes 
of openings  
3 Terms and definitions   
For the purposes of this standard, the following terms and definitions apply .  
3.1 
gravel  
product resulting from natural disintegration and human actions  such abrasion of rock or processing of weakly 
bound conglomerate  
3.2 
uncrushed  gravel  
product resulting from screening and blending of material from the deposit, consisting of particles with a shape 
and texture largely dependent on the nature of the depos it 
3.4 
crushed gravel  
product resulting from the crushing  of rocks,  with a requirement that at least a prescribed percentage  of the 
resulting particles have fracture faces  
  
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3.5 
aggregate  
granular material used in construction, such as sand, gravel, crushe d stone, used with a cementing medium 
such as hydraulic cement or bituminous binder, to form hydraulic -cement concrete or mortar or asphalt concrete  
3.6 
coarse aggregate  
aggregate of particle size retained on a square aperture test sieve of 4.75 mm nominal  size not exceeding 37.5 
mm 
3.7  
fine aggregate  
aggregate of particle size passing a square aperture test sieve of 4.75 mm nominal size  
3.8 
grading  
particle size distribution expressed as the percent ages by mass passing a specified set of sieves  
3.9 
surfacing  
layer or layers of processed material constructed upon the completed base. Surfacing is sometimes referred to 
as "wearing course".  
3.10 
slurry seal  
homogenous mixture of asphalt emulsion, graded fin e aggregates, mineral fille  and water that has a creamy 
fluid-like appearance  when applied  
 DRS 292: 2023  
3                ©RSB 2023 - All rights reserved  
 4 Geometrical requirements  
4.1 General  
Aggregate sizes shall conform to the requirements prescribed in Table 1  for the size number specified. 
Conformance shall be determ ined by means of laboratory sieves having square openings complying with RS 
ISO 565.  
Table 1 — Sizes of processed aggregates  
Sieve size 
(mm)                              Percent age passing by mass  
26.5 mm 
nominal 
size 19.0 mm 
nominal 
size 13.2 mm 
nominal 
size 9.5 mm 
nominal 
size 6.7 mm 
nominal 
size 4.75 mm 
nominal 
size 2.36 mm 
Nominal 
size 
37.50  100 - - - - - - 
26.50  85-100 100 - - - - - 
19.00  0-30 85-100 100 - - - - 
13.20  0-5 0-30 85-100 100 - - - 
9.50 - 0-5 0-50 85-100 100 - - 
6.70 - - 0-10 0-50 85-100 100 - 
4.75 - - - 0-10 0-50 85-100 100 
3.35 - - - - - 0-30 - 
2.36 - - - - 0-5 0-10 0-100 
4.2 Selection of aggregates   
The size of the aggregate shall vary with the thickness of the surface course desired and with the type of 
construction contemplated, as described in Table 2.  
Table 2 — Single -sized coarse aggregates  
Sieve designation  
(mm)  percent age passing for single -sized aggregates of nominal size  
26.5 mm 19.0 mm  13.2 mm  9.5 mm 6.7 mm  2.36 mm  
37.5  100 - - - - - 
26.5  85-100 100 - - - - 
19.0  0-30 85-100 100 - - - 
13.2  0-5 0-30 85-100 100 - - 
9.5  - 0-5 0-50 85-100 - - 
6.7  - - 0-10 0-50 100 - 
4.75  - - - 0-10 0-30 100 
2.36  - - - - 0-10 100 
  
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 4.3 Sizes and grading  of aggregates  
4.3.1  General  
The grading of the aggregate  shall be determined  by sieving  in accordance with  RS 96 -4. 
4.3.2  Single -sized  coarse aggrega tes  
Coarse aggregates shall be supplied in the nominal sizes given in Table 2. For any one of the nominal sizes, 
the proportion of other sizes shall also be in accordance with Table 2.  
4.3.3  Fine aggregates  
The grading of fine aggregates shall be within the limits given in Table 3 and shall be described as fine 
aggregate s, Grading Zones I, II, III and IV. Where the grading falls outside the limits of any particular grading 
zone  of sieves other than 600 μm s ieve by a total amount not exceeding 5 %, it shall be regarded as falling 
within that grading zone. This tolerance shall not be applied to percen tage passing the 600 μm sieve or to %age 
passing any other sieve size on the coarse limit of Grading Zone I .  
Table 3  — Grades of fine aggregates  
Sieve designation  Percent age passing for aggregate zones  
Grading zone I  Grading zone II  Grading zone III  
10 mm 100 100 100 
4.75 mm 90-100 90-100 90-100 
2.36 mm 60-95 75-100 85-100 
1.18 mm 30-70 55-90 75-100 
600 µm 15-34 35-59 60-79 
300 µm 5-20 8-30 12-40 
150 µm 0-10 0-10 0-10 
NOTE  For crushed stone sands, the permissible limit on 150 μm sieve is increased to 20  %. - As the fine aggregate grading 
becomes progressively finer, that is, from Grading Zones I to III, the ratio of fine aggregate to coarse aggregate is progres sively 
reduced. The most suitable fine to coarse ratio to be used for any particular mix, however, depends upon the actual grading, 
particle shape and surface texture of both fine and coarse aggregates.  
5 Aggregate for slurry seal  
5.1 Aggregate for use in slurry seal shall be an approved crusher sand obtained from a parent rock that has 
an ACV not exceeding 30 % or a mixture that consists of such crusher sand and not more than 25 % of approved 
clean natural sand.  
5.2 The aggregate shall  be clean, tough, durable and angular, and shall comply with the relevant grading 
requirements of Table 4 for the slurry and the grade or type of aggregate specified.  DRS 292: 2023  
5                ©RSB 2023 - All rights reserved  
 Table 4 — Grading limits of aggregate for slurry seal  
Nominal 
aperture size  
mm Fine slurr y Coarse slurry  
Fine grade  Medium grade  Coarse grade  Type 1  Type 2  
Percent age (by mass) passing sieve  
13.2 - - - - 100 
9.5 - - - 100 85-100 
6.7 - 100 100 85-100 70-90 
4.75 100 82-100 70-90 70-90 60-80 
2.36 90-100 56-95 45-70 45-70 40-60 
1.18 65-95 37-75 28-50 25-45 25-45 
0.600  42-72 22-50 19-34 15-30 15-30 
0.300  23-48 15-37 12-25 10-20 10-20 
0.150  10-27 7-20 7-18 6-15 10-20 
0.075  4-12 4-12 2-8 4-10 4-10 
6 Physical requirements  
6.1 General  
The basic requirements for fine and coarse are summarised in Table 5  and detailed from 6.2 to 7.5.  
Table 5 — Physical and Mechanical properties of aggregates  
Parameter   Requir ement  Test method  
Physical properties  
Water absorption  ≤ 1.5 %  ASTM C 127  
Density  ≥ 2 000 kg/m3  The test sample shall be dried at the 
temperature of 105 ± 50C for 24 hours  
Soundness  Fine aggregates ( limits 
for weighted loss:)  ≤10 %, when tested with sodium 
sulphate (Na2SO4)  
≤15 %, when tested with 
magnesium sulphate (MgSO4)  ASTM C 88  
Coarse aggregates  
(limits for weighted 
loss:)  ≤ 12 %, when tested with sodium 
sulphate (Na2SO4)  
≤ 18 % when tested with 
magnesium sulphate (MgSO4)  ASTM C 88   
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 The flakiness index  ≤ 15 %. RS 96 -5 
Deleterious substances  ≤ 1.0 %  
3.0 % 75 µm   
Mechanical properties  
Aggregate crushing value  
 ≤ 30 %  
 RS ASTM C535: 2016  
Ten percent fines value  
 ≤ 210 kN RS 96 -8 
Aggregate impact value  
 ≤ 30%.  
 RS 96 -9 
Aggregate abrasion value  
 ≤ 30 %  ASTM C 131  
6.2 Water absorption  
Water absorption , when determined in accordance with ASTM C 127, shall not exceed 1.5 %.  
6.3 Density  
The minimum oven dried particle density of aggregates shall be 2 000 kg/m3. The test sample shall be dried at  
the temperature of 105 ± 5°C for 24 h .  
6.4 Soundness  
The aggregate, when subjected to five cycles of the soundness test according to ASTM C 88, shall not exceed 
the following limits for weighted loss:  
a) for fine aggregates:  10 % when tested with sodium sulphate (Na 2SO 4) and 15 % when tested with 
magnesium sulphate  (MgSO 4); and  
b) for coarse aggregates:  12 % when sodium sulphate ( Na2SO 4) is used or 18 % when magnesium sulphate 
(MgSO 4) is used.  DRS 292: 2023  
7                ©RSB 2023 - All rights reserved  
 6.5 Flakiness  index  
The flak iness index of the coarse aggregate s, when tested in accordance with the method given in RS 96 -5, 
shall not be more than 15 %.  
6.6 Deleterious substances  
6.5.1  Aggregate shall not contain any harmful material, such as pyrites, coal, lignite, mica, shale or similar 
laminated material, clay, alkali, soft fragments and organic impurities in such quantity as to  affect the strength 
durability of road surface.  
6.5.2  The maximum quantity of deleterious substances shall not exceed 1.0 % by mass. For substances finer 
than 75 µm, the quantity of deleterious substances shall not exceed 3.0 %.  
7 Mechanical  properties  
7.1 Aggregate crushing value  
The aggregate crushing value  shall be determined according to ISO 20290 -3 and shall not exceed 30  % of 
original mass . 
NOTE 1  The aggregate crushing value gives a relative measure of the resistance of coarse aggregate to crushing under 
a gradually applied compressive load.  
NOTE 2  The aggregate crushing value test is made on aggregate passing a 12.5  mm sieve and retained on a 10 mm 
sieve.  
7.2 Ten percent fines value  
The ten percent fines value shall be determined in accordance with RS 96 -8, and shall not be less than 210 kN  
7.3 Aggregate impac t value  
The aggregate impact value  for coarse aggregate, when determined in accordance with RS 96 -9 shall not 
exceed 30%.  
NOTE  The aggregate impact value gives a relative measure of the resistance of an aggregate to sudden shock or 
impact, which in some ag gregates differs from its resistance to a slow compressive load.  
7.4 Aggregate abrasion value  
The aggregate abrasion value  for coarse aggregate , when determined  according to ASTM C 131 , shall not 
exceed  30 % . 
  
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8 Sampling and testing  
8.1 Sampling  
The method of samp ling shall be determined in accordance with RS 96 -3. 
8.2 Testing   
8.2.1  All tests shall be carried out as described in  RS 96 -4 to RS 96 -12 and other relevant referenced test 
methods . 
8.2.3  In the case of all -in-aggregate, for purposes of tests to verify its compliance with the limit requirements 
given in 6.5, and when necessary for such other tests as required by the purchaser, the aggregate shall be first 
separated into two fractions, one f iner than 4.75 mm sieve and the other coarser than 4.75 mm sieve, and the 
appropriate tests shall be made on samples from each component, the former being tested as fine aggregate 
and the latter as coarse aggregate.  
9 Supplier’s certificate  
9.1 The supplier shall satisfy himself that the material complies with the requirements of this standard and, if 
requested, shall supply a certificate to this effect to the purchaser.  
9.2 If the purchaser requires independent tests to be made, the sample for such tests sha ll be taken before 
or immediately after delivery according to the option of the purchaser, and the tests carried out in accordance 
with this standard and on the written instructions of the purchaser.  
9.3 The material required for tests shall be supplied fr ee of charge  
 
 DRS 292: 2023  
9                ©RSB 2023 - All rights reserved  
 Bibliography  
[1] IRC: 15 -2011 , Standard specifications and code of practice for construction of concrete roads ( fourth 
revision  
[2] ASTM D448 – 12, Standard Classification for Sizes of Aggregate for Road and Bridge Construction  DRS 292: 2023  
 
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