Components of highway pavement and materials used. Soil: Importance, Desirable properties, Index properties, Compaction, Strength evaluation tests. Aggregate: Functions, Desirable properties, Tests on road aggregates and quality control. Bituminous binders: Functions, Desirable properties, Tests on bitumen and quality control, Bitumen emulsion functions and classification, Modified bituminous binder functions and classification. Bituminous Mix: Desirable properties and requirement of design mix, general approach for design of bituminous mixes and introduction to Marshall Mix Design Method

1. “HIGHWAY
MATERIALS”
1
PREPARED BY : ASST. PROF. VATSAL D. PATEL
MAHATMA GANDHI INSTITUTE OF
TECHNICAL EDUCATION &
RESEARCH CENTRE, NAVSARI.

2. COMPONENTS OF HIGHWAY ON
EMBANKMENT
 Highway structures are generally constructed above the
general ground level and called highway in embankment.
 It has following components :
 Embankment or fill
 Sub grade
 Drainage layer
 Shoulders
 Pavement layers
(flexible or rigid)

3. COMPONENTS OF HIGHWAY ON
EMBANKMENT
Provide Wearing surface
Binder course load transfer
Base-Load transfer
Upper subbase-
Drainage layer
Lower sub-
base-
separation
layer
Bituminous
Layer
Non-bituminous
layer
BC-Bituminous Concrete
PC-Premix carpet
SDBC-Semi Dense Bituminous Concrete
OGPC- Open graded pre-mix carpet
Surface/Wearing course -Name Binder course-Name
BM-Bituminous macadam
PC-Premix carpet
DBM-Dense Bituminous Macadam
BUSG- Built Up Spray Grout
Base course
WBM-Water
bound
Macadam
Lower Granular sub base- Close graded –Grad I and II
Upper Granular sub base- Open graded –Grad III, IV
WMM-Wet
Mix
Existing soil OR Ground –Known as Subgrade
Shoulder- Provide support
Carriage way

4. CROSS SECTION OF FLEXIBLE
PAVEMENT
Prime coat
Tack coat Slope –known as
camber

5. CROSS SECTION OF RIGID
PAVEMENT / CONCRETE ROAD
Granular Sub base / Drainage layer
Dry Lean Concrete-DLC Sub
Base
2 lane Carriage way
Shoulder
Shoulder
Compacted Subgrade / Borrowed
subgrade
Pavement Quality Concrete –
PQC Slab
Joint
Separation
membrane

6. MATERIALS USED FOR
PAVEMENT CONSTRUCTION
 Sub grade – Soil - Borrowed sub grade/ Compacted sub
grade / Existing soil
 Sub-base - Granular soil or crushed aggregates
 Base course - Crushed stone aggregates (Metal/ Black trap
metal) and fine aggregates/ Stone dust / Sand
 Binder course and Wearing course - Crushed stone
aggregates (Metal/ Black trap metal) and fine aggregates/
Stone dust / Sand + Bitumen (binder) in Flexible
pavement + Cement in concrete pavement

7. MATERIALS USED FOR
PAVEMENT CONSTRUCTION
 Classified materials used for it :
Soil
• Used as
subgrade
• Subgrade
may be
borrowed
(compacted)
Aggregate
• Used in
granular
sub base
• Used in
granular
base course
• Used in
bituminous
layer
Binder-
BITUMEN
• Used in
binder
course
• Used in
wearing
course
Binder-
CEMENT
• Used in
Dry lean
concrete
(DLC)
• Used in
Pavement
Quality
Concrete
(PQC)

8. HIGHWAY CONSTRUCTION
MATERIAL
Soil Aggregate Bitumen Cement

9. SOIL
 Soil is mineral material lying above rock strata including
air, water, and organic matter.
 It is non-homogeneous and porous.
 Properties greatly influenced by moisture, density and
compaction.
 To identify soil and its behaviour is complex and need skill
and experience.

10. DESIRABLE PROPERTIES OF SOIL
Physical Properties
• G-Specific Gravity,
• OMC- Optimum moisture
content
• MDD- Maximum dry density
• FMC -Field Moisture content
• FDD – Field dry density
• GSA-Grain size analysis
• Atterberg’s limit /
Consistency limits
• LL-Liquid limit
• PL-Plastic limit
• PI-Plasticity Index
• SL- Shrinkage limit
Engineering Properties
• C-Cohesion,
• ø – Friction,
• K -Permeability,
• FSI- Free swell Index
• CBR- California Bearing
ratio,
• K -Modulus of Subgrade,
• SBC- safe bearing capacity.
• UCS-Unconfined
Compressive strength
(Preferred in IRC 37)

11. DESIRABLE PROPERTIES OF SOIL
• Adequate stability
to resist permanent
deformation under
loads
1.
Stability
• Minimum variation
in volume, ensures
mini. differential
expansion and
strength values
2.
Incompressibility
• Should retain
desired sub grade
support i.e.
Resistance to
weathering
3.
Strength
• Under adverse
conditions of
weather and
ground water
minimum change
in volume
4 . Minimum
volume
changes
• Essential to avoid
excessive moisture
retention and to
reduce the potential
frost action
5. Good
drainage
• Ensures higher dry
density and
strength under
particular type and
amount of
compaction
6 . Ease of
compaction

12. INDEX PROPERTIES OF SOIL
 The wide range of soil types available as highway
construction materials have made it obligatory on the part
of the highway engineer to identify and classify the different
soils.
 The soil properties on which their identification and
classification are based are known as index properties.

13. INDEX PROPERTIES OF SOIL
 The following index properties are used for classification of
soils :
 Grain size distribution
 Liquid limit ( wL )
 Plasticity index ( Ip )
 Shrinkage limit ( wS )
 Field moisture equivalent
 Compacted dry density

14. INDEX PROPERTIES OF SOIL
 Grain size distribution :
 Particle size distribution is a method of separation of soils
into different fractions based on the particle size. It is also
known as mechanical analysis.

15. INDEX PROPERTIES OF SOIL
 Consistency limits :
 The consistency of a fine-grained soil is the physical state in
which it exists. It is used to denote the degree of firmness of
a soil. Consistency of a soil is indicated by such terms as
soft, firm, stiff or hard.
 In 1911, a Swedish agriculture engineer Atterberg
mentioned that a fine grained soil can exist in four states,
namely, liquid, plastic, semi-solid or solid state. The water
contents at which soil changes from one state to the other
are known as consistency limits or Atterberg’s limit.

16. INDEX
PROPERTIES
OF SOIL
The water content at
which the soil
changes from the
liquid state to the
plastic state is known
as liquid limit (wL).
OR
The minimum water
content at which soil
starts getting shear
strength, is called
liquid limit.
Liquid limit (wL ) :

17. INDEX
PROPERTIES
OF SOIL
The water content at
which the soil
changes from plastic
state to the semi-
solid state is known
as plastic limit (wP).
OR
It is defined as the
min. water content at
which a soil will just
begin to crumble
when rolled into a
thread of approx.
3mm in diameter.
Plastic limit (wP ) :

18. INDEX
PROPERTIES
OF SOIL
The water content at
which the soil
changes from semi-
solid state to the
solid state is known
as shrinkage limit
(wS).
OR
It is the maximum
water content below
which soil does not
remain saturated, is
called shrinkage
limit.
Shrinkage limit (wS ) :

19. COMPACTION
Light Compaction/
Standard Proctor
Particle size
20 mm
Maximum
Small Mould
10 cm Dia,
12.73 cm Height
Sample size 19
mm passing
Quantity 5 Kg
3 – layer, 25 Blow
2.6 Kg Hammer
31 cm Fall Height
Particle size
37.5 mm
Maximum
Large Mould
15 cm Dia,
17.5 cm Height
Sample size 40
mm passing
Quantity 6 Kg
3 – Layer, 55 Blow
2.6 Kg Hammer
31 cm Fall Height
Heavy Compaction/
Modified
Compaction
Particle size
20 mm
Maximum
Small Mould
10 cm Dia,
12.73 cm Height
Sample size 19
mm passing
Quantity- 5 Kg
5 – layer, 25 Blow
4.9 Kg Hammer
45 cm Fall Height
Particle size
37.5 mm
Maximum
Large Mould
15 cm Dia,
17.5 cm Height
Sample size 40
mm passing
Quantity 30 Kg
5 – layer , 55 Blow ,
4.9 Kg Hammer
45 cm Fall Height
For less
important
road
For Most
important
road

20. COMPACTION
Dynamic compaction
Soil sample passing from 19
mm ( size > 19 mm shall be
replaced by material passing
through 19 mm and retained
on 4.75 mm)
Soil sample weight (dry)
required @ 6 kg
Water added as per lab OMC
Mould prepared by applying
hammer blow-at 5 layer of 2.6
or 4.9 Kg at its OMC and MDD
Test immediately- UN SOAK
test
Test after soaking 96 hours in
water- SOAK CBR test
Static compaction
Soil sample passing from 19 mm ( size > 19
mm shall be replaced by material passing
through 19 mm and retained on 4.75 mm)
Volume of soil =2209 cc
Now this soil would fill the mould
If required apply compression force—at
compression test m/c
Test immediately- UN SOAK test
Test after soaking 96 hours in water-
SOAK CBR test

21. STRENGTH EVALUATION TESTS
Evaluation of Soil Strength
Shear test
Direct shear
test
(Box shear
test)
Unconfined
compressio
n test (UCS)
Triaxial
Compression
test
Bearing test
Plate
bearing test
Measure-
Modulus of
subgrade
reaction – K
value
Used for
Thickness
Design of
Concrete
Pavement
(Rigid
Pavement)
Penetration
test
California
bearing
Ratio Test
(CBR) -%
Used for
Thickness
Design of
Flexible
Pavement

22. FUNCTIONS OF AGGREGATE
 Aggregates are the prime material used in the flexible
pavement construction.
 Aggregate bear stresses due to wheel loads coming over the
pavement and also they have to resist wear due to abrasive
action of traffic.
 They are used in pavement construction in cement
concrete, bituminous concrete and other bituminous
construction.

23. DESIRABLE PROPERTIES OF ROAD
AGGREGATE
 The desirable properties of aggregates used in road
construction are :
 Strength
 Hardness
 Toughness
 Durability
 Shape of aggregates

24. DESIRABLE PROPERTIES OF ROAD
AGGREGATE
 Strength :
 The aggregates to be used in road construction should be
sufficiently strong to withstand the stresses due to traffic
wheel road.
 The aggregates which are to be used in top layers of the
pavements (wearing courses) have to be capable of
withstanding high stresses in addition to wear and tear.

25. DESIRABLE PROPERTIES OF ROAD
AGGREGATE
 Hardness :
 The aggregates used in the surface course are subject to
constant rubbing or abrasion due to moving traffic.
 They should be hard enough to resist the wear due to
abrasive action of traffic.
 Abrasive action may be increased due to the presence of
abrasive material like sand between the tyres of moving
vehicles and the aggregates exposed at the top surface.
 This action may be severe in the case of steel tyred vehicles.

26. DESIRABLE PROPERTIES OF ROAD
AGGREGATE
 Toughness :
 Aggregates in the pavement layers are also subjected to
impact due to moving wheel loads.
 The magnitude of impact would increase with the
roughness of the load surface, the speed of the vehicle and
other vehicular characteristics.
 The resistance to impact is called toughness, which is
another desirable property of aggregates.

27. DESIRABLE PROPERTIES OF ROAD
AGGREGATE
 Durability :
 The stone used in pavement construction should be durable
and should resist disintegration due to the action of
weather.
 The property of the aggregates to withstand the adverse
action of weather may be called soundness.

28. DESIRABLE PROPERTIES OF ROAD
AGGREGATE
 Shape of aggregates :
 The shape of aggregate may be rounded, cubical, angular,
flaky or elongated.
 The flaky and elongated particles will have less strength
and durability when compared with cubical, angular or
rounded particles of the same stone.
 Hence, too flaky and too much elongated aggregates should
be avoided as far as possible.

29. BITUMEN
 Bitumen is petroleum product, obtained by the distillation
of petroleum crude oil.
 Bitumen is hydrocarbon material of either natural or
pyrogenous origin found in gaseous, liquid, semisolid or
solid form and is completely soluble in carbon disulphide
and in carbon tetra chloride.
 Bituminous materials are commonly used in highway
construction ( Binder and surface/wearing course) because
of their binding and water proofing properties.

30. BITUMEN BINDERS
 Bituminous binders are adhesive materials that contain
bitumen, which may be in the form of conventional
bitumen, modified bitumen or bitumen emulsion.
 The term “bitumen” refers to a material that is non-volatile,
adhesive and waterproof which is derived from crude oil or
present in natural asphalt.

31. TYPES OF BITUMEN BINDERS
 Types of Bituminous binders used in Flexible pavement
construction :
 Paving grade bitumen :
 Viscosity grade bitumen- VG 10, VG 20, VG 30, VG 40
 Modified bituminous binder :
 Polymer modified bitumen -PMB
 Crumb rubber modified bitumen - CRMB

32. TYPES OF BITUMEN BINDERS
 Types of Bituminous binders used in Flexible pavement
construction :
 Cutback bitumen :
 Rapid curing cutback (RC)
 Medium Curing cutback (MC)
 Slow curing cutback ( SC)
 Bitumen Emulsion :
 Rapid Setting emulsion (RS)
 Medium Setting emulsion (MS)
 Slow Setting emulsion ( SS)

33. DIFFERENCE BETWEEN BITUMEN
AND TAR
BITUMEN TAR
Produced from fractional
distillation of petroleum crude
Produced from coal by
destructive distillation
Less temperature susceptible High temperature susceptible
Used in road construction Not used in road construction
Sp. Gravity range 0.97 to 1.02 Sp. Gravity range 1.10 to 1.25
More resistance to water Less resistance to water
Soluble in Carbon disulphide CS2
and carbon tetra chloride CCl4
Soluble in Toluene- C7H8
Free carbon content is less More Free carbon content

34. DIFFERENCE BETWEEN BITUMEN
AND TAR
Bitumen Tar Emulsion Cutback
Produced
from
fractional
distillation of
petroleum
crude
Produced from
coal by
destructive
distillation
Prepared by dispersing
bitumen in the form of
fine globules
suspended in WATER
with the help of
suitable EMULSIFIER
Prepared by diluting a
paving grade bitumen
with volatile solvent
such as KEROSENE
Less
temperature
susceptible
High
temperature
susceptible
Used for Prime coat
and Tack coat and
other cold mix
Currently not used in
road construction
activity
Used in road
construction
Not used in road
construction
Available in
Rapid setting,
Medium setting and
Slow setting
Available in
Rapid setting,
Medium setting and
Slow setting
Sp. Gravity
range 0.97 to
1.02
Sp. Gravity range
1.10 to 1.25

35. DESIRABLE PROPERTIES OF
BITUMEN
 Low cost
 Strength
 Workability
 Durability
 Imperviousness
 Cohesion
 Adhesion
 Minimal sensitivity to aging

36. TESTS ON BITUMEN
CONSISTENCY
TESTS OF
BITUMEN
Penetration
test (IS:1203-
1978)
Softening
point test
(IS:1205-1978)
Viscosity test:
Absolute and
Kinematic
AGING TESTS
ON BITUMEN
Thin film
oven test
(ASTM-D-
1754/IS:9283)
SAFETY TESTS
ON BITUMEN
Flash and
Fire point test
(IS: 1209-1978)
OTHER
TEST
Specific Gravity
test on bitumen
(IS: 1202-1978)
Ductility test
(IS: 1208-1978)
Solubility
Test
(IS:1212-1978)

37. MODIFIDE BITUMEN BINDERS
 The viscosity of ordinary paving grade bitumen varies
considerably with temperature, as a result the bituminous
pavement surface course also becomes susceptible to
temperature changes.
 During hot weather, the bituminous surface course
becomes soft resulting in possibility of pavement
deformation and early rutting along the wheel paths of
heavy vehicles.
 During cold weather, the bituminous pavement surface
course becomes too stiff and brittle resulting in early
cracking under repeated application of heavy wheel loads.

38. MODIFIDE BITUMEN BINDERS
 Functions :
 The bitumen modifier reduce the temperature susceptibility
of the binder, resulting in pavement stability by imparting
visco-elastic properties to the mix.
 They reduces pavement deformation or rutting of the
bituminous surface course under traffic loads.
 They prevent early cracking of pavement surface course in
winter, under repeated application of heavy wheel loads.
 They improve durability of bitumen mixes.
 Better adhesion between aggregate and binder.

39. TYPES OF MODIFIER
 Polymers :
 LDPE - Low density polyethylene
 SBS - Styrene Butadiene styrene
 SBR - Styrene Butadiene rubber
 EVA - Ethylene vinyl Acetate
 EBA - Ethylene Butyl Acetate
 ETP - Ethylene tar polymer
 Rubbers :
 Crumb rubber - with and without additives
 Natural rubber - Latex powder, rubber powder

40. CLASSIFICATION OF MODIFIER
 IS 15462 : 2004 classify the polymer and rubber
modified bitumen into following four types :
 Type A – PMB (P) : Plastomeric thermoplastic based
 Type B – PMB (E) : Elastomeric thermoplastic based
 Type C – NRMB : Natural rubber and SBR latex based
 Type D–CRMB : Crumb rubber treated crumb rubber based

41. REQUIREMENTS OF BITUMINUS
MIXES
 The surface course (top layer) of flexible pavements of
important roads has to withstand high stress conditions
and wear and tear due to traffic loads. In addition, the
surface course is exposed to adverse climate factors
including temperature variations, water etc.
 Therefore, properly designed high quality bituminous
mixes are laid on the surface course of flexible pavements
of important roads so as to sustain heavy traffic loads and
wear and tear due to high speed vehicle movement.
 Thus, high stability, durability and good skid resistance are
the basic requirements of bituminous Surface course.

42. REQUIREMENTS OF BITUMINUS
MIXES
 Stability is defined as resistance of the paving mix to
deformation. Stability is a function of friction and cohesion.
 Durability is defined as the resistance of the mix against
weathering and abrasive actions.
 Skid resistance is defined as the resistance of the finished
pavement against skidding and is a function of Surface
texture and bitumen content.

43. DESIRABLE PROPERTIES OF
BITUMINUS MIXES
 Adequate stability :
 The bituminous mix should possess adequate stability to
withstand stresses and deformations due to repeated
application of wheel loads.
 Stability may be achieved by selecting suitable type and
grading of aggregates, appropriate binder and its
proportion.
 Adequate flexibility :
 The bituminous mix should possess adequate flexibility to
withstand fatigue effect and development of cracks.
 This can be achieved by selection of proper mix of
aggregates and binder.

44. DESIRABLE PROPERTIES OF
BITUMINUS MIXES
 Durability :
 It should possess adequate durability to sustain the
combined effect of adverse weather conditions and
repeated traffic loads.
 Adequate durability can be achieved by arriving at correct
bitumen binder content during mix design to ensure
adequate thickness of binder film around the aggregate
particles.
 Stiffness :
 The bituminous nix should possess adequate stiffness, i.e.
resistance to permanent deformation such as rutting due to
movement of heavy wheel loads.

45. DESIRABLE PROPERTIES OF
BITUMINUS MIXES
 Adequate resistance to cracking :
 The bituminous mix should possess adequate resistance to
low temperature cracking under traffic movement. This can
be achieved by selection of suitable type and grade of
bituminous binder.
 Sufficient air voids :
 The bituminous mix should contain sufficient air voids to
prevent "bleeding‘ of the binder as a consequence of further
densification of bituminous mix under traffic movements
and also reduction of skid resistance under wet conditions.

46. DESIRABLE PROPERTIES OF
BITUMINUS MIXES
 Resistance to Moisture induced change :
 Resistance to Moisture induced changes may be achieved
by minimising permeability of the compacted bituminous
mix, selecting appropriate binder quality and adequate
binder content.
 Adequate skid resistance :
 This can be achieved by selecting aggregates with suitable
texture, shape, gradation and ensuring good resistance to
polishing or high polished stone value of the coarse
aggregates in the mix.

47. DESIRABLE PROPERTIES OF
BITUMINUS MIXES
 Adequate workability :
 The hot bituminous mix should have adequate workability
at the mixing, laying and compacting temperatures.

48. GENERAL APPROACH FOR
DESIGN OF BITUMINOUS MIXES
 Selection of aggregate :
 The aggregates which possess sufficient strength, hardness,
toughness, soundness and polished stone value are chosen.
 Crushed aggregates and sharp sands produce higher
stability of the mix when compared with gravel and
rounded sands.

49. GENERAL APPROACH FOR
DESIGN OF BITUMINOUS MIXES
 Selection of aggregate grading :
 The properties of bituminous mix like density and stability
are very much dependent on the type of aggregates and
their grain size distribution.
 As higher maximum size of aggregate gives higher stability,
usually the larger size that can be adopted depends on the
compacted thickness of the pavement layer.
 Maximum aggregate size of 25 to 50 mm are used in the
bituminous mixes for base course and 12.5 to 18.7 mm size
are use for surface course.

50. GENERAL APPROACH FOR
DESIGN OF BITUMINOUS MIXES
 Determination of specific gravity of components :
 If the specific gravity of the bituminous material is known,
it is not required to be determined. The specific gravity of
aggregates is represented as either bulk specific gravity or
apparent specific gravity.
 In bulk specific gravity the overall volume of the aggregates
(including capillaries) is taken. In apparent specific gravity
the volume of capillaries which are filled by water on 24
hours soaking is excluded.

51. GENERAL APPROACH FOR
DESIGN OF BITUMINOUS MIXES
 Proportioning of aggregates :
 First of all the design grading is decided based on the type
of construction, thickness of the layer and availability of
aggregates.
 Then the available aggregates are proportioned (blended)
by one of the following methods :
 Analytical method
 Graphical method
 Trial and error method

52. GENERAL APPROACH FOR
DESIGN OF BITUMINOUS MIXES
 Preparation of test specimens :
 The preparation of test specimens depends on the stability
test. Hence the size of specimen, compaction and other
specifications should be followed as specified in the
selected test method.
 Steps for preparing test specimens :
 Heating the required weight of mixed aggregates to the
desired temperature.
 Heating the required weight of bitumen at specified
maximum temperature.

53. GENERAL APPROACH FOR
DESIGN OF BITUMINOUS MIXES
 Steps for preparing test specimens :
 Mixing the aggregates and binder in laboratory mixer at
specified mixing temperature, depending on the type and
grade of binder.
 Transferring the hot mix to the mould and compacting as
specified in the test method.
 Removing the test specimen from the mould and cooling to
room temperature.
 At least 3 test specimens are prepared in each trial binder
content so that the mean of three test values could be
utilized.

54. GENERAL APPROACH FOR
DESIGN OF BITUMINOUS MIXES
 Determination of specific gravity of compacted
specimen :
 Before conducting stability test, the weight and volume of
each compacted specimen is determined and the density of
the compacted mix is calculated.
 With known values of specific gravity of aggregates and
bitumen, the theoretical maximum specific gravity of the
mix is calculated.

55. GENERAL APPROACH FOR
DESIGN OF BITUMINOUS MIXES
 Determination of some of air voids, voids in
mineral aggregates and voids filled with bitumen :
 The percentage air voids in the compacted specimen of the
mix is calculated using values of specific gravity of test
specimen and the theoretical maximum specific gravity of
the mix.

56. 56