Sub grade soil is an integral part of the road pavement structure as it provides the support to the pavement from beneath. The sub grade soil and its properties are important in the design of pavement structure. The main function of the sub grade is to give adequate support to the pavement and for this the sub grade should possess sufficient stability under adverse climatic and loading conditions.

1. M.Senthamizhan
Assistant Professor / Civil
Alagappa Chettiar Government College of Engineering and Technology, Karaikudi
Tamilnadu

2. CONTENT
Highway Materials – Properties andTests
 Subgrade Soil
 Stone Aggregates
 Bituminous Material
 Concrete
Highway Construction
 Flexible Pavement
 Rigid Pavement
Highway Drainage
 Surface Drainage
 Sub Surface drainage
Highway Construction Machineries

3. Subgrade Soil

4.  Subgrade soil is an integralpart of the road
pavement structure as it provides the support to the
pavement from beneath.
 The sub grade soil and its properties are
important in the design ofpavement structure.
 The main function of the subgrade is to give
adequate support to the pavement and for this the sub
grade should possess sufficient stability under adverse
climatic and loading conditions.

5. The desirable properties of sub grade soil as a highway material
are
I. Withstand capability (Stability)
II. Ease of compaction.
III. Strength permanency
IV. Low change in volume during adverse conditions of weather
and ground water table.
V. Superior drainage
VI. Incompressibility

6. Classification of Soil based on grain size

7. Textural Classification of Soil

8. Subgrade
Soil
Shear Test
Direct Shear
Test
Triaxial
Compression
Test
Unconfined
Compression
Test
Bearing Test
Plate Bearing
Test
Penetration
Test
CBR Test
The tests used to evaluate the strength properties of soils may be broadly
divided into three groups:

24. Stone Aggregates

25. The major portion of the pavement structure
Bear the stresses occurring due to the wheel loads
on the pavement
Used in pavement construction, cement concrete,
bituminous concrete and other bituminous
construction
Most of the road aggregates are prepared from
natural rocks
They are specified based on their grain size, texture
and its gradation

26. The desirable properties of stone aggregate as a highway material
are
I. Strength
II. Hardness
III. Toughness
IV. Durability
V. Shape of Aggregates
VI. Adhesion of Bitumen

27. The tests used to
evaluate the strength
properties of stone
aggregates
TestsonStoneAggregate
Crushing Test
Abrasion Test
Los Angeles
Abrasion
Deval
Abrasion
Dorry
AbrasionImpact Test
Soundness Test
Shape Test
Flakiness
Index
Elongation
Index
Angularity
Number
Specific
Gravity
Water
Absorption Test
Bitumen Adhesion
Test

48.  Bitumen adheres well to all normal types of road aggregates provided they are
dry and free from dust. In the absence of water there is practically no adhesion
problem of bituminous construction.
 Adhesion problem occurs when the aggregate is wet and cold. This problem
can be dealt with by removing moisture from the aggregate by drying and
increasing the mixing temperature.
 Further, the presence of water causes stripping of binder from the coated
aggregates. This problem occurs when bitumen mixture is permeable to water.
 Several laboratory tests are conducted to arbitrarily determine the adhesion
of bitumen binder to an aggregate in the presence of water. Static immersion
test is one specified by IRC and is quite simple.
 The principle of the test is by immersing aggregate fully coated with binder
in water maintained at 400C temperature for 24 hours.

50. Bituminous Material

51.  Bituminous binders used in pavement construction works
include both bitumen and tar
 Bitumen is divided into two category as Petroleum Asphalt or
bitumen and Natural Asphalt.
 The grades of bitumen used for pavement construction work of
roads and airfields are called paving grades
 Those used for water proofing of structures and industrial
floors etc. are called industrial grades
A – Type : Paving Bitumen from Assam Petroleum,
Grades are A35 and A90
S – Type : Paving Bitumen from Other sources,
Grades are S35 and S90

53. The desirable properties of Bitumen as a highway material are
I. Mixing
II. Attainment of desired stability of the mix
III. To maintain the stability under adverse weather conditions
IV. To maintain sufficient flexibility and thus avoid cracking of
bitumen surface
V. To have sufficient adhesion with aggregates in the mix in the
presence of water.
VI. The material should be durable

54. TestsonBitumen
Penetration Test
Ductility Test
Viscosity Test
Float Test
Specific Gravity Test
Softening Test
Flash & Fire Point test
Solubility Test
Spot Test
Loss on Heating Test
Water Content Test
The tests used to evaluate
the strength properties of
Bitumen

69. Pavement

70. PAVEMENT-
Pavement is load bearing and load distributery component of a road.
PURPOSE OF PAVEMENT-
1. Load support.
2. Smoothness.
3. Drainage.
4. All weather operation.
5. Direction and guidance.

72. Flexible Pavement

74. Flexible pavement:Flexible pavements are so named because
the total pavement structure deflects, or flexes, under
loading. A typically composed of several layers of material.

75. STRUCTURE OF FLEXIBLE PAVEMENT

76. Load distribution in flexible pavement

78. Subgrade: The subgrade is the compacted soil layer that
forms the foundation of the pavement system. It is also
known as the "Formation Level“.

79. CONSTRUCTION OF SUBGRADE
(a)Removal of top soil (If not suitable for sub grade or
to match the level)
(b)Removal of vegetation and other harmful material
(c)Lay down the Soil in layers of 266mm (max.)
(d)Compaction of Layer ( After Compaction Max. depth
should be 200mm)
(e)Further Layer of Soil
(f)Compaction of Layer

80. PREPARATION OF SUBGRADE

85. PREPARATION OF BASE COURSE

89. The aggregate to be used for the BM layer shall fulfil the
specified gradation. Two type of aggregate gradation have been specified
by the IRC which is as given below table

90.  The base on which bituminous macadam is to be laid shall be
prepared, shaped and compacted to the required profile.
 The prime coat and take coat are applied as specified.
 The BM mix is prepared in a hot mix plant at specified temperature,
depending on the grade of the bitumen used.
 The hot mix is transported to the construction site in insulated
covered truck.
 The BM mix is spread using a mechanical paver.
 Bituminous materials shall be laid and compacted in layers, which
enable the specified thickness, surface level, regularity
requirements and compaction to be achieved.

96. Binder course:This layer provides the bulk of the asphalt
structure. It's main purpose is to distribute load.

97. PREPARATION OF BINDER COURSE

98. Tack coat : it is high viscous bituminous material(100% bitumen)

100. Surface Course: The surface course is the layer in contact with
traffic loads and normally contains the highest quality materials.

101. Seal coat: It is the asphalt-water mixture to seal cracks on surface layer.

102. Rigid Pavement

103. • Rigid pavements, though costly in initial investment, are cheap in long
run because of low maintenance costs, The cost of construction of
single lane rigid pavement varies from 35 to 50 lakhs per km in plain
area,
Rigid pavement have-
 Deformation in the sub grade is not transferred to subsequent layers
 Design is based on flexural strength or slab action
 Have high flexural strength
 No such phenomenon of grain to grain load transfer exists
 Have low repairing cost but completion cost is high
 Life span is more as compare to flexible (Low Maintenance Cost)

106. PROCEDURE TO CONSTRUCT THE RIGID PAVEMENT ROAD
Preparation
of Subgrade
Preparation
of Base
Form
Working
Watering of
Base
Joints
Material &
Placing
Compaction
Finishing of
Surface
Curing
Joint Filling
Edging
Open to
Traffic

107. 1. Rolling on sub grade by roller
2. Filling the granular soil in the weak part and pot holes
3. Correct the soil coat , Camber , longitudinal slope
When concrete direct laid on subgrade, For preventing
the water-seepaging into the soil , used water proof paper
on entire length.

108. PREPERATION OF SUB GRADE

109. Choose any one type of base
1. W.B.M. base
As base material of W.B.M. Road; stone ballast, concrete 10-15cm
layer are used. For bonding between concrete slab & W.B.M. used 1:2
cement wash on W.B.M.
2. Concrete base
On the road used 10cm Cement concrete(1:2:4) or lime concrete
3. Granular medium material layer
10-15cm composite layer of sand , moorum are used for better drainage
facilities
4. Stabilization soil

110. Material for form work-
Wooden sheets, battens, plywood, fibre hard board, steel plates,
angles, rope, minerals.
1.Before using form work, it should free from all type material like as dust
,cement.
2.To placing the concrete in appropriate depth used 2.5-5cm thick and 3mtr
long wooden sheeting.
3. The depth of wooden block must be same as level of slab thick.
4. After 24hrs form work displaced next length of road.

113.  Where is necessary to provide transverse, Longitudinal
joints; there wedge of woods, metals fix on level of concrete.
 After setting of concrete it should be pull out.
 If provided the dowel bar in joints, bars should be fit at
right position.

114. Mixer is equipment that mix the concrete using distinct amount of cement ,
concrete, sand and water. Concrete slab should have more than 5-10cm thick cause
of drying.
Used two type mixer-
1. Batch mixer-
at site, used for small road construction
2. Continuous mixer-
Continuous mixer used for large construction . if distance is more from
site, mix concrete transported at site within setting time.

117. Purpose of compaction is that to pull out air from void and make
concrete harden.
1.Mechanically surface vibrator
2. Manually hand tempers

118. 8. Finishing of Surface
1.Floating-
For levelling the surface use
floating, scree- ding , power trowel.
So that there is no acceptable more
than 3mm variation in concrete level
surface.
2.Belting-
For making surface clean used
belting process. Belt is nothing but a
15-30cm thick sheets of canvass
which have more length than road.

119. 8. Finishing of Surface
3. Brooming-
 Brooming is the process in
which we made rough surface
parallel to road by brush.
 It useful in avoiding slip &
comfortable travelling on
road .
 The depth of line on road
no more than 1.5mm.

120. 9. Curing
Curing is the name of
increasing the hydration
process of cement. After
setting the concrete, curing
process done till 14-28days.

121. 10. Filling Joint
After drying road, clean the
joints and fill the shelling
compound or hot bitumen
also bitumen fill road bank.

122. 11. Edging
To protect damaging the
sides of concrete
pavements used over burnt
brick work. In place of brick,
provided kerb of pre mix
concrete.

123. Generally after a month,
road should be open to traffic.
If used rapid hardening cement
it take 7 days to open traffic.

124. TypeofJoints
Perpendicular to
Traffic Flow
Expansion Joint
Contraction Joint
Construction Joint
Parallel to Traffic
Flow
Longitudinal Joint
Type of Joints in Rigid Pavement

126. Highway
 Highway drainage is a process of removing and controlling excess
surface and sub-soil water within the right of way.
 It includes interception and diversion of water from the road surface and
subgrade.

127.  Excessmoisture -lowering of its stability and strength in Pavement
 Sustained contact of water - potholes
 Excesswater on shoulders - considerable damage.
 In clayey soil variation in moisture content – Change in volume of sub
grade.
 Erosion of soil from top of unsurfaced roads and slopes of embankment,
cut and hill side is also due to surface water.
 In cold regions presence of water in the subgrade and a continuous
supply of water from the ground water can cause considerable damage to
the pavement due to frost action.

128.  The surface water - drained off without allowing it to percolate to sub grade.
 Side drain should have sufficient capacity and longitudinal slope to carry away all
surface water collected.
 Flow of surface water across the road and shoulders and along slopes should not cause
formation of crossruts or erosion.
 Seepage and other sources of under ground water should be drained off by the
subsurfacedrainagesystem.
 Highest level of ground water table should be kept well below the level of
subgrade, preferably by at least 1.2m.
 In waterlogged areas special precautions should be taken, especially if detrimental
salts are present or if flooring is likely to occur.

129. Highway
Drainage
Surface
Drainage
Longitudinal Side Drains
Catch Basin and Inlet
Shoulder Drainage
Median Drainage
Sub Surface
Drainage
Lowering of Water Table
Controlling Seepage Flow
Controlling Capillary Water

130. a. Side Drain for Road Embankment b. Side Drain for Road cutting

131. a. Catch Basin b. Inlet

135. a. Above the subgrade of pavement b. At or below the subgrade of pavement