This document provides information on bitumen, which is used as a binding material in pavements. It discusses the types of bitumen including paving grade, modified, cutback and emulsion. Cutback bitumen has solvents added to increase fluidity while bitumen emulsion uses water. Modified bitumen has additives added to improve properties. The document also describes various tests conducted on bitumen like penetration, ductility, softening point and viscosity to determine hardness and grading. Bitumen requirements include adequate viscosity and adhesion properties. The grading of bitumen depends on the results of penetration tests.

2. Contents
 Introduction
 Types
 Properties
 Tests on Bitumen
 Grading of Bitumen

3. Introduction
 Used in pavements
 Binding material
 Used in
 wearing course
 Primer
 Patch works
 Surface dressing etc.,
 Bitumen, Tar are not same.

4. Bitumen and Tar
 Black or dark colored solid, viscous
cementitious substance.
 Bitumen is petroleum product – obtained
by distillation of crude petroleum or
naturally available in asphalt.
 Coal tar – by product in destructive
distillation of coke

5. Bitumen and Tar
 Bitumen
 Excellent Binding properties
 Good water proofing surface
 Tar
 Highly temperature susceptible
 Pollutant
 Poor adhesion in presence of water
 Bitumen preferred over Tar

6. Bitumen - Definition
According to ASTM -
“Bitumen is hydrocarbon material of either
natural or pyrogenous origin found in
gaseous, liquid, semi-solid or solid form
and is completely soluble in carbon-di-
sulphide , carbon tetra chloride”

7. Bitumen - Intro
 Definition
 At normal range of temp – semi solid state
 When heated viscosity decreases
 For construction of pavements – heated
from 130 to 175C
 Mixing with aggregates at high temp – Hot
bituminous mix
 Mixing with aggregates at low or normal
temperature – Cold bituminous mix

8. Grades of Bitumen
 Bitumens can be majorly classified into
2 types
 Paving grade bitumen: Used for construction
of roads and airfields
 Industrial grade bitumen: water proofing of
structures and industrial floors etc.,

9. Types
 Paving grade bitumen
 Modified bitumen binders
 Cutback bitumen
 Bitumen Emulsion

10. Cutback bitumen
 To have fluid consistency at normal
temp, with low heating – cutback
bitumen is used
 Dilution of paving grade in volatile
solvents – kerosene, light fuel oil etc.,
 Hardening rate depends on the grade
and characteristics of bitumen and
solvent.
 RC, MC, SS

11. Cutback bitumen
 RC is recommended for surface
dressing and patchwork.
 MC is recommended for premix with
less quantity of fine aggregates.
 SS is used for premix with appreciable
quantity of fine aggregates.

12. Bitumen Emulsion
 To get fluid consistency
 Dispersing bitumen globules in aqueous
solution (i.e., water with dispersing
agent)
 60% water, remaining bitumen
 Cold bituminous mix
 Properties depend on grade, water
quantity, emulsifier
 RS, MS, SS

13. Modified Bitumen Binders
 To improve the properties of bitumen
 Additives are mixed
 Polymer modified bitumen is used only
in wearing course depending on the
severity of climatic and weather
conditions

14. Advantages of modified
bitumen
 Lower susceptibility to daily and seasonal
temperature variations
 Higher resistance to deformation at high
pavement temperature
 Better age resistance properties
 Higher fatigue life for mixes
 Better adhesion between aggregates and
binder
 Prevention of cracking and reflective
cracking

15. Functions of Binders
 Used in surface course
 Used in base course depending on
traffic
 Used in preparation of mixes
 Used as prime coat over granular base
course
 Used in soil stabilization
 Sealer material for filling joints, cracks in
cc pavements

16. Requirements
 Adequate viscosity
 Heating bitumen, aggregate
 Cutback
 Emulsion
 Sufficiently viscous on cooling – compact
surface with no deformation
 Form thin film around aggregates
 Sufficient ductility
 Temp susceptibility
 Adhesion with aggregates in presence of
water
 affinity between the materials used in the mix

17. Tests on Bitumen
 Penetration test
 Ductility test
 Softening point test
 Specific gravity test
 Viscosity test
 Flash and fire point test
 Float test
 Water content test
 Loss on heating test

18. Penetration test
 Measures hardness or softness of
bitumen
 Measures penetration depth in tenths of
a millimeter to which a standard loaded
needle will penetrate in 5 sec
 Standardized equipment – BIS
 Penetrometer device – consists a
needle, weight of 100g, device for
releasing and locking position

19. Penetration test setup – Rough
diagram

20. Penetrometer

21.  Bitumen heated to pouring consistency
 Placed in containers to a depth i.e.,
min15mm excess of expected
penetration
 Conducted at 25C
 Highly fluctuated with small inaccuracy
 Results are used for grading the
bitumen i.e., 40/50 or 80/90 etc.,
bitumens

22. Ductility test
 It is the property that permits bitumen to
undergo great deformation without
breaking
 Ductility is defined as the distance in cm,
to which a standard sample or briquette
of the material will be elongated without
breaking

23.  The bitumen sample is heated and
poured in the mould assembly placed on
a plate
 Cooled in air and then kept in waterbath
at 27C
 Sides are removed
 Attached to a machine
 Minimum ductility is 75cm

24. Ductility Mould

27. Softening point test
 Ring and Ball
 Temperature at which the bitumen attains a
particular degree of softening
 Brass Ring containing test sample
 Suspended in liquid (water, glycerin etc.,)
 Heating @5C/Min
 Softening point denotes the temp at which
bitumen touches the base metal plate.

32. Specific Gravity Test
 Used for classification
 Density influenced by chemical
composition
 Using pycnometer method or any other
standard method
 0.97 to 1.02

33. Viscosity Test
 It is fluid property of bitumen
 Measure of resistance to flow
 Influences the strength of resulting mixes
 Very low and high viscosity decreases the
stability of mix
 High viscosity – non homogenous mix
 Low viscosity – no uniform film on aggregates,
just lubricates
 Orifice type viscometer and other types of
equipment is used
 Time noted for receiving specific quantity of bitumen
material through orifice

34. Flash and Fire point test
 High temperatures – Bitumen leaves
volatiles
 These are inflammable
 Important to know at where it catches fire
 According to BIS, flash point is the
temperature at which the vapour of the
bitumen momentarily catches fire in the
form of flash.
 Fire point is the temperature at which the
material gets ignited and burns
 Flash point should be min 175C

35. Water content test
 Bitumen distilled in petroleum
 Heated
 Wait of water condensed and collected
is expressed as the percentage by
weight of original sample
 Allowable maximum water content
should not be more than 0.2% by weight

36. Loss on Heating Test
 Bitumen loses volatility upon heating and gets
hardened
 50gms of sample is weighed and heated to
163C for 5 hours
 Sample weighed after heating
 Loss in weight is expressed as the percentage
by weight of the original sample.
 For paving mixes not more than 1% is allowed
 How ever, if the bitumen has penetration
values of 150 -200mm 2% is allowed.

37.  Thankyou