8/11/2019 Pavement Design Kiran Biradar
1/18
BYKIRAN BIRADAR
PAVEMENT DESIGN
8/11/2019 Pavement Design Kiran Biradar
2/18
Introduction
Pavement design is the major component in the
road construction.
Nearly one-third or one-half of the total cost ofconstruction , so careful consideration should be
taken in design of pavement.
Type of pavements:
Flexible pavement
Rigid pavement
Semi-rigid pavement
8/11/2019 Pavement Design Kiran Biradar
3/18
Factors which affect the selection of these
pavements
Initial cost
Availability of good materials
Cost of maintenance
Environmental conditions
Availability of industrial wastes
Traffic intensity
8/11/2019 Pavement Design Kiran Biradar
4/18
Design parameters
General:
Criteria for determining the pavement (flexible)
Thickness is vertical compressive strain comes to the
subgrade due to the standard axle laden of magnitude8.17 kN (8170 kg) , if more than this causes permanentdeformation in form of rutting. The maximum ruttingcan be accepted in village road as 50 mm before
maintenance and the analytical evaluation can be doneaccording to IRC:37.
For rigid and semi-rigid pavement tensile stress is takenas the design criteria.
8/11/2019 Pavement Design Kiran Biradar
5/18
Traffic:
As per the IRC:37 design traffic should be 0.1 msa to2 msa (million standard axles).
Weight of commercial vehicle (laden) is consideredas 3 tonnes or more.
For design traffic we consider the existing traffic and
rate of growth.Traffic study should be done as per the IRC:9.
8/11/2019 Pavement Design Kiran Biradar
6/18
Design life:
The no. of years to be taken until the majorreconstruction.
Design life depend upon the environmentalconditions, materials used ,maintenance etc.
For rural roads design life of 10 years is considered.
In low volume roads for the thin bituminoussurfacing design life of 5 years is considered.
8/11/2019 Pavement Design Kiran Biradar
7/18
Computation of design traffic:
a=p(1+r)^(n+x)
Where,a=no. of commercial vehicles/day for design
p=no. of commercial vehicles/day at last count
r=annual growth rate of commercial traffic
n=no. of years between last count and year ofcompletion of construction
x=design life in years
8/11/2019 Pavement Design Kiran Biradar
8/18
Pavement components
Subgrade Sub-base course
Base course Surface course
8/11/2019 Pavement Design Kiran Biradar
9/18
Subgrade:
To provide support to the pavement as itsfoundation.
Top 30 cm of the cutting or embankment atformation level in rural roads consider as subgrade.
A minimum of 100% of standard proctorcompaction should be attain in subgrade.
For clayey soil 95% and moisture content of 2% inexcess of optimum value.
Soil below subgrade should be compacted to 97% ofstandard proctor compaction.
8/11/2019 Pavement Design Kiran Biradar
10/18
CBR:
Conduct on sample which remoulded at OMC anddry density.
Test should be done per km depend on soil type.
If CBR less than 2% for 100 mm thickness thenminimum CBR of 10% is to be provided to the sub-base for CBR of 2%.
If CBR more than 15% , no need to provide sub-base.
8/11/2019 Pavement Design Kiran Biradar
11/18
Sub-base course:
Selected materials placed on subgrade which iscompacted to 98% of IS heavy compaction.
Function of sub-base is to distribute the stressesover a wide area of the subgrade imposed by thetraffic.
Materials: CBR of 15%
Passing through 425 micron IS sieve
L.L
8/11/2019 Pavement Design Kiran Biradar
12/18
Waste material such as
Fly ash
Iron and steel slag Recycled concrete
Municipal waste
When subgrade is silty or clayey soil and annual
rainfall of area is more than 1000 mm, a drainagelayer of 100 mm then formation width should beprovided.
8/11/2019 Pavement Design Kiran Biradar
13/18
Base course:
to with stand high stress concentrations whichdevelop due to traffic under the wearing surface.
Different types of base course used are:
WBM
Crusher-run macadam
Dry lean concrete Soft aggregate base course
Lime-fly ash concrete
8/11/2019 Pavement Design Kiran Biradar
14/18
Surface course:Thickness of surface course depend upon the traffic volumeand type of material used for it.
For gravel roads extra thickness should be provided because
of lost in thickness due to the traffic action.
Bituminous wearing courses must be made up of good quality
aggreagate with aggreagate impact value not exceeding 30 %
in order to reduce degradation of aggregates by crushing.
8/11/2019 Pavement Design Kiran Biradar
15/18
8/11/2019 Pavement Design Kiran Biradar
16/18
8/11/2019 Pavement Design Kiran Biradar
17/18
8/11/2019 Pavement Design Kiran Biradar
18/18