ICS 91.100.50; 93.080.20  
 
Reference number  
DRS  395-1: 2023 
© RSB 2023 
  
 RWANDA 
STANDARD  DRS 
395-1  
 
Second edition  
2023-mm-dd 
 
Bitumen and bituminous binders  — 
Part 1 : Terminology  
   
DRS  395-1: 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  
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Toll Free: 3250  
E-mail: info@rsb.gov.rw  
Website: www.rsb.gov.rw  
ePortal: www.portal.rsb.gov.rw   DRS  395-1: 2023 
iii                ©RSB 2023 - All rights reserved  
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ ...................  iv 
1 Scope  ................................ ................................ ................................ ................................ .............  1 
2 Normative references  ................................ ................................ ................................ ...................  1 
3 Terms and definitions  ................................ ................................ ................................ ..................  1 
Annex  A (normative)  Types of hydrocarbon binders  ................................ ................................ ...........  8 
 DRS  395-1: 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 of technical committees is to prepare national standards.  Final Draft Rwanda S tandards adop ted 
by Technical committ ees are ratified  by me mbers of RSB Board of Director s for publication and gazettment as 
Rwanda Standards.  
DRS 395-1 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) BS 12591: 2009 , Bitumen and Bituminous Binders  
2) ASTM D673  - 16, Standard Specification for Performance Graded Asphalt Binder  
The assistance de rived from the above source is hereby acknowledged with th anks.  
This second edition cancels and replaces the first edition (RS  395-1: 2018 ), [clau ses 3] which has been 
technically revised.  
DRS 395 consists of the following parts, under the general title Bitumen and bituminous binders  —: 
⎯ Part 1: Terminology  
⎯ Part 2: Specification for paving grade bitumen  
⎯ Part 3: Specification for bituminous emulsion (under development)  
Committee membership  
The following organizations were represented on the Technical Committee on Roads and highway engineering  
(RSB/TC 55) in the preparation of this standard.  
ASTRIK International Ltd  
EDITRACE LTD  and General Reliance  
JV CSC&EC(Property) and Fair Construction Ltd  
MININFRA  
NPD Ltd  DRS  395-1: 2023 
v                ©RSB 2023 - All rights reserved  
 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  395-1: 2023 
1                ©RSB 2023 - All rights reserved  
 Bitumen and bituminous binders — Part 1: Terminology  
1 Scope  
This Draft Rwanda Standard defines terms for paving or industrial bitumen of various types and binders derived 
from bitumen.  
It does not extend to non -petroleum “hydrocarbon” binders such as coal tar and its derivatives or to natural 
asphalts. However, some definiti ons are given for some excluded materials and related terms. The 
corresponding terms were introduced only when they appeared in a definition of a product or process and when 
their definition was found necessary for understanding or for avoiding any ambigui ty. 
NOTE The types covered by this Standard are shown in Annex A. The figure also shows a clear distinction 
between materials inside and outside the scope of this standard.  paragraph.  
2 Normative references   
There are no normative references in this  document .  
3 Terms and definitions   
For the purposes of this standard, the follow ing terms and definitions apply . 
3.1 
binder  
material serving to adhere to aggregate and ensure cohesion of the mixture  
3.2  
hydrocarbon binder  
generic term for an adhesive material c ontaining bitumen, or tar, or both bitumen and tar  
Note 1 to entry  1: This term is not scientifically precise, in that all of the materials covered by the term contain non -
hydrocarbon components. However, the term has been included to allow the term “bitum inous binder” (3.3.2) to apply 
exclusively to non -pyrolysis material, i.e. bitumen.  
3.3 
bitumen  
virtually not volatile, adhesive and waterproofing material derived from crude petroleum, or present in natural 
asphalt, which is completely or nearly complete ly soluble in toluene, and very viscous or nearly solid at ambient 
temperatures   
©RSB 2023 - All rights reserved                  2 
 Note 1 to entry:  Some grades of bitumen are used in both paving and industrial applications,  Example certain penetration -
graded bitumen are used for industrial purposes such as  in the manufacture of roofing felts and other waterproofing 
membranes.  
3.3.1  
bituminous  
adjective applicable to binders, to mixtures of binders and aggregates and more generally to any material 
containing bitumen  
3.3.2  
bituminous binder  
adhesive material containing bitumen  
Note 1 to entry:  A bituminous binder may be in any of the following forms: unmodified, modified, oxidized, cutback, fluxed, 
emulsified.  
Note 2 to entry:  To avoid uncertainty, whenever possible the term describing the actual binder in question is used.  
3.4 
paving bitumen  
bitumen used to coat aggregate and/or reclaimed asphalt, mainly used in the construction and maintenance of 
paved surfaces and hydraulic works  
Note 1 to entry: In Rwanda, the most -used grades of paving bitumen are defined by their needle  penetration at 2 5 °C, up to 
a maximum value of 900 × 0 .1 mm. Grades softer than this are designated as given in 3.4.1.  
3.4.1  
soft grade bitumen   
paving bitumen used in the manufacture of low stiffness asphalt  
Note 1 to entry: Bitumen grades are specified primarily in ter ms of their needle penetration (referred to as 'pen'), soft bitumen 
has high pen number. Also, the grades of soft grade bitumen can be defined by their viscosity at 60 °C. 3.4.2  
3.4.2  
hard grade bitumen  
bitumen possessing hard and brittle characteristics at ambient temperature  
Note 1 to entry: Bitumen grades are specified primarily in terms of their needle penetration (referred to as ' pen') , hard bitumen  
have low pen numbers.   DRS  395-1: 2023 
3                ©RSB 2023 - All rights reserved  
 3.4.3  
air-rectified bitumen   
bitumen that has been subjected to mild oxidation with the goal of producing a bitumen meeting paving grade 
bitumen specifications  
Note 1 to entry:  Air-rectified bitumen has a penetration index PI ≤ +2.0. 
3.5  
modified bitumen  
bituminous binder whose rheological properties have been modified during manufacture by the use of one or 
more chemical agents  
Note 1 to entry:  n this context, “chemical agent” includes natural rubber, synthetic polymers, waxes, sulfur and certain 
organo -metallic compounds, but not oxygen or oxidation “catalysts” such as ferric chloride, phosphoric acid and phosphorus 
pentoxide. Fibres and inorganic powders (“fillers”) are not considered to be bitumen modifiers. Modified bitumen may be 
employed “directly” or in the form of cut -backs or emulsions, or blended with (for example) natural asphalt.  
3.5.1  
polymer modified bitumen  
is bitumen modified by combining  with one or more  organic  polymer materials  or rubber  (typically styrene -
butadiene -styrene (SBS) copol ymer) . This modification is done with the aim of enhancing the mechanical 
properties of the bitumen material. Polymer modified bitumen is typically used on road pavements, particularly 
those that are intended to withstand heavy -duty traffic and extreme wea ther conditions.  
3.6  
special bitumen  
bitumen for which the process selected has conferred special properties which meet requirements for paving or 
industrial applications  
3.6.1  
multigrade bitumen  
special bitumen for road applications which is less tempe rature susceptible than paving grade bitumen and 
having a penetration index PI positive  
Note 1 to entry: Multigrade bitumen is manufactured from the same sources as conventional bitumen but requires processing 
to reduce temperature susceptibility. This pr ovides some of the advantages of increased binder stiffness at higher 
temperatures while retaining satisfactory low -temperature characteristics.  
Note 2 to entry: Multigrade may be used for high -stress seals and in place of conventional bitumen  in high‑temperature 
areas.   
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 3.7  
industrial bitumen   
bitumen used for purposes other than the construction or maintenance of paved surfaces  
3.7.1  
oxidized bitumen  
bitumen whose rheological properties have been substantially modified by reaction with air at elevated 
temperatures  
Note 1 to entry:  Oxidized bitumen have a penetration index PI > +2.0 
3.7.2  
hard industrial bitumen  
bitumen for industrial applications possessing hard and brittle characteristics at ambient temperature  
Note 1 to entry:  Hard industrial bitumen products are graded by the limits of the ring and ball sof tening point values, 
expressed as multiples of 5, and are characterized by an H in front of the values  
3.8 
flux/cut-back solvent   
fluid added to another to reduce its viscosity  
Note 1 to entry:  These fluids are derived from various sources including mineral or vegetal origin products  
3.8.1  
flux or flux oil  
relatively involatile fluid (oil) used in the manufacture of fluxed bitumen  
3.8.2  
solvent for cut -back  
relatively volatile fluid used in the manufacture of cutback bitumen  
Note 1 to entry: Solvent is any substance, usually liquid, which is capable of dissolving one or several substances, thus 
creating a solution . 
3.9 
cut-back bitumen whose viscosity has been reduced by the ad dition of a cut -back solvent (3.8.2)  DRS  395-1: 2023 
5                ©RSB 2023 - All rights reserved  
 Note  1 to entry: Typically, white spirit and kerosine are the petroleum fluxes employed.  
3.9.1  
petroleum cut -back bitumen  
bitumen whose viscosity has been reduced by the addition of a cut -back solvent derived from pet roleum  
Note 1 to entry: Typically, white spirit and kerosine are the petroleum derived fluxes employed.  
3.10 
fluxed bitumen  
bitumen whose viscosity has been reduced by the addition of low flux oil(s) (3.8.1)  
Note 1 to entry:  A petroleum -fluxed bitumen i s so called when the flux oil is of petroleum origin.  
3.10.1  
bio-fluxed bitumen  
bitumen whose viscosity has been reduced by the addition of a flux oil derived from vegetal or animal oils  
3.10.2  
carbochemical fluxed bitumen  
bitumen whose viscosity has been reduced by the addition of a flux derived from coal tar based products  
Note 1  to entry:  Carbochemical products are obtained from coal pyrolysis.  
3.10.3  
petroleum fluxed bitumen  
bitumen whose viscosity has been reduced by the addition of a flux oil derived from petroleum  
Note 1 to entry:  Typically, gas oils of various distillation ranges are used as flux.  
3.11 
emulsion  
fluid system in which bitumen droplets and/or liquid crystals are dispersed in a water  
Note 1 to entry:  Dispersion is thermodynamically metastable.  Type of emulsifier, Natural (vegetable - agar, tragacan th, 
animal souce wool fat, gelatin   
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 3.11.1  
dispersed phase  
liquid which has been dispersed in the continuous phase  
Note 1 to entry:  The “dispersed phase” is also referred to as the “discontinuous phase”.  
3.11.2  
continuous phase  
liquid in which the disper sed/discontinuous phase has been dispersed  
Note 1 to entry:  This is normally an aqueous solution.  
3.11.3  
emulsifier  
surfactant which when present in small amounts facilitates the formation of an emulsion, or enhances its colloidal 
stability  
3.11.4  
bitum inous emulsion  
dispersion of bitumen in an aqueous phase containing a surfactant  
Note 1 to entry:  Unless otherwise stated, continuous phase is assumed to be aqueous solution.  
3.11.4.1  
anionic bituminous emulsion  
emulsion in which the emulsifier imparts negative charges to the dispersed bitumen droplets  
3.11.4.2  
cationic bituminous emulsion  
emulsion in which the emulsifier imparts positive charges to the dispersed bitumen droplets  
3.11.4.3  
polymer -modified bit uminous emulsion  
emulsion in which the dispersed phase is a polymermodified bitumen or a bitumen emulsion modified with 
polymer latex  DRS  395-1: 2023 
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 3.12  
asphalt  
mixture of aggregates and bituminous binder  
3.13  
natural asphalt  
relatively hard bitumen found in natu ral deposits, often mixed with fine or very fine mineral matter, which is 
virtually solid at 25 °C but which is a viscous fluid at 175 °C  
 
 
 
 
 
 
 
 
 
 
  
©RSB 2023 - All rights reserved                  8 
 Annex  A 
(normative)  
 
Types of hydrocarbon binders  
 
 
 
 
 
 
 
 
 
DRS  395-1: 2023 
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  DRS 395-1: 2023 
 
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