This document provides information on flexible pavement design and theory. It discusses the typical layers of a flexible pavement including the surface course, base course, and subgrade. It also outlines several factors that affect pavement design such as wheel load, climate, and material characteristics. Additionally, the document examines failures like fatigue cracking and rutting that pavement design aims to prevent. It provides guidance on mechanistic-empirical design as prescribed by the Indian Roads Congress.
Design of rigid pavements. IRC method of design of rigid pavement. Transportation Engineering. Civil Engineering. Wheel loads on rigid pavement. Action of various stresses on rigid pavement. Highway engineering. How rigid pavements different from flexible pavements
Design of rigid pavements. IRC method of design of rigid pavement. Transportation Engineering. Civil Engineering. Wheel loads on rigid pavement. Action of various stresses on rigid pavement. Highway engineering. How rigid pavements different from flexible pavements
types of pavement materials
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The Benkelman beam is the simplest and the oldest deflection
test device, developed in the United States in the mid-1950s. Its used to measure the structural capacity of a flexible pavement.
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
types of pavement materials
types of paving material
types of road pavement
types of flexible pavement
flexible pavement of road construction
types of pavement for driveways
types of rigid pavements
asphalt pavement types
types of flexible pavements
flexible pavement design
flexible pavement manual
flexible pavement construction
flexible pavement vs rigid pavement
flexible pavement design example
flexible pavement of road construction
flexible pavement ppt
types of rigid pavements
rigid pavement design
rigid pavement pdf
rigid pavement construction
rigid pavement design example
rigid pavement construction michigan
aashto rigid pavement design
aashto rigid pavement design spreadsheet
The Benkelman beam is the simplest and the oldest deflection
test device, developed in the United States in the mid-1950s. Its used to measure the structural capacity of a flexible pavement.
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
Pavement materials in Road Constructionsrinivas2036
Different pavement materials used in the road construction. Importance of soil, aggregate pavement materials. Tests on Soil for pavement construction. Tests on aggregate for pavement construction.
Requirements of soil and aggregates in pavement.
Study on comparative flexible pavement thickness analysis using various desig...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
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A highway pavement is a structure consisting of superimposed layers of processed materials above the natural soil sub-grade, whose primary function is to distribute the applied vehicle loads to the sub-grade. The pavement structure should be able to provide a surface of acceptable riding quality, adequate skid resistance, favorable light reflecting characteristics, and low noise pollution.
Pavement deterioration is a serious problem for road and traffic sector in almost every country, the most
affecting causes of bituminous pavement failures have been studied in this paper. The paper describes the
lessons learnt from pavement failures and problems experienced. Failures of bituminous pavements are caused
due to many reasons or combination of reasons. Application of correction in the existing surface will enhance
the life of maintenance works as well as that of strengthening layer. Along with the maintenance techniques
there are various methods for pavement preservation which will help in enhancing the life of pavement and
delaying of its failure.This paper discusses the possible causes of pavement failures, and recommendbetter ways
to minimize and hopefully eliminate the causes of failures in bituminous pavements.
Democratizing Fuzzing at Scale by Abhishek Aryaabh.arya
Presented at NUS: Fuzzing and Software Security Summer School 2024
This keynote talks about the democratization of fuzzing at scale, highlighting the collaboration between open source communities, academia, and industry to advance the field of fuzzing. It delves into the history of fuzzing, the development of scalable fuzzing platforms, and the empowerment of community-driven research. The talk will further discuss recent advancements leveraging AI/ML and offer insights into the future evolution of the fuzzing landscape.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
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Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
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Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
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• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
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• Remote control system for accessing CCR and allied system over serial or TCP.
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Automobile Management System Project Report.pdfKamal Acharya
The proposed project is developed to manage the automobile in the automobile dealer company. The main module in this project is login, automobile management, customer management, sales, complaints and reports. The first module is the login. The automobile showroom owner should login to the project for usage. The username and password are verified and if it is correct, next form opens. If the username and password are not correct, it shows the error message.
When a customer search for a automobile, if the automobile is available, they will be taken to a page that shows the details of the automobile including automobile name, automobile ID, quantity, price etc. “Automobile Management System” is useful for maintaining automobiles, customers effectively and hence helps for establishing good relation between customer and automobile organization. It contains various customized modules for effectively maintaining automobiles and stock information accurately and safely.
When the automobile is sold to the customer, stock will be reduced automatically. When a new purchase is made, stock will be increased automatically. While selecting automobiles for sale, the proposed software will automatically check for total number of available stock of that particular item, if the total stock of that particular item is less than 5, software will notify the user to purchase the particular item.
Also when the user tries to sale items which are not in stock, the system will prompt the user that the stock is not enough. Customers of this system can search for a automobile; can purchase a automobile easily by selecting fast. On the other hand the stock of automobiles can be maintained perfectly by the automobile shop manager overcoming the drawbacks of existing system.
Courier management system project report.pdfKamal Acharya
It is now-a-days very important for the people to send or receive articles like imported furniture, electronic items, gifts, business goods and the like. People depend vastly on different transport systems which mostly use the manual way of receiving and delivering the articles. There is no way to track the articles till they are received and there is no way to let the customer know what happened in transit, once he booked some articles. In such a situation, we need a system which completely computerizes the cargo activities including time to time tracking of the articles sent. This need is fulfilled by Courier Management System software which is online software for the cargo management people that enables them to receive the goods from a source and send them to a required destination and track their status from time to time.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
Vaccine management system project report documentation..pdfKamal Acharya
The Division of Vaccine and Immunization is facing increasing difficulty monitoring vaccines and other commodities distribution once they have been distributed from the national stores. With the introduction of new vaccines, more challenges have been anticipated with this additions posing serious threat to the already over strained vaccine supply chain system in Kenya.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
TECHNICAL TRAINING MANUAL GENERAL FAMILIARIZATION COURSEDuvanRamosGarzon1
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1. FLEXIBLE PAVEMENT
THEORY AND DESIGN
Guide : Dr. Shashikant Sharma,
Assistant prof. Civil engineering department.
NATIONAL INSTITUTE OF TECHNOLOGY, HAMIRPUR
DEPT. OF CIVIL ENGINEERING, 2016
3. What is pavement ?
A structure consisting of superimposed layers of
processed materials above the natural soil sub-
grade, whose primary function is to distribute the
applied vehicle loads to the sub-grade.
26/10/20163
5. Flexible pavement:
26/10/20165
Flexible pavements are those which on a whole have
low or negligible flexural strength and rather flexible
in their structural action under load.
6. Load transfer:
26/10/20166
Load is transferred to the lower layer by grain to
grain distribution as shown in the figure given below;
7. Load Transfer (continue …)
26/10/20167
The wheel load acting on the pavement will be
distributed to a wider area, and the stress decreases
with the depth. Flexible pavement layers reflect the
deformation of the lower layers on to the surface
layer
8. TYPICAL LAYERS OF A FLEXIBLE
PAVEMENT :
26/10/20168
Typical layers of a conventional flexible pavement
includes seal coat, surface course, tack coat, binder
course, prime coat, base course, sub-base course,
compacted sub-grade, and natural sub-grade.
9. TYPICAL LAYERS OF A FLEXIBLE
PAVEMENT
26/10/20169
Seal coat is a thin surface treatment used to water-
proof the surface and to provide skid resistance.
Tack coat is a very light application of asphalt
emulsion diluted with water. And It provides bonding
between two layers of binder course.
Prime coat is an application of low viscous cutback
bitumen to an absorbent surface like granular bases
on which binder layer is placed and provides
bonding between two layers.
10. TYPICAL LAYERS OF A FLEXIBLE
PAVEMENT (Continue ….)
26/10/201610
Surface course is the layer directly in contact with
traffic loads and are constructed with dense graded
asphalt concrete.
Binder course purpose is to distribute load to the
base course. Binder course requires lesser quality of
mix as compared to course above it.
Base course provides additional load distribution
and contributes to the sub-surface drainage
11. TYPICAL LAYERS OF A FLEXIBLE
PAVEMENT (Continue ….)
26/10/201611
Sub-base course the primary functions are to
provide structural support, improve drainage, and
reduce the intrusion of fines from the sub-grade in
the pavement structure
Sub-grade The top soil or sub-grade is a layer of
natural soil prepared to receive the stresses from the
layers above
13. Design Wheel Load.
26/10/201613
Max. Wheel load - It is used to determine the depth
of the pavement required to ensure that the
subgrade soil does not fail.
Contact pressure - It determines the contact area and the
contact pressure between the wheel and the pavement
surface. For simplicity elliptical contact area is consider to
be circular.
14. Design Wheel Load (Continue)
26/10/201614
Axle configuration - the axle configuration is important to
know the way in which the load is applied on the pavement
surface.
16. Design Wheel Load (Continue)
26/10/201616
Repetition of loads :
Each load application causes some deformation and the
total deformation is the summation of all these.
Although the pavement deformation due to single axle
load is very small, the cumulative effect of number of load
repetition is significant.
Therefore, modern design is based on total number of
standard axle load (usually 80 KN single axle)
17. Climatic Factor
26/10/201617
1. Temperature -
Wide temperature variations may cause damaging
effects.
Pavement becomes soft in hot weather and brittle in very
cold weather.
2. Variation in moisture condition –
It depends on type of the pavement, type of soil type,
ground water variation etc.
It can be controlled by providing suitable surface and sub-
surface drainage.
18. Characteristic of Pavement material
26/10/201618
1. California bearing ratio- It determines the strength
of soil sub-grade, sub-base or base and it is used for
the design of pavement.
2. Elastic modulus -It measures the materials
resistance to being deformed elastically upon
application of the wheel load.
3. Poisson Ratio – It is the ratio of lateral strain to the
axial strain caused by a load parallel axis along axial
strain.
4. Resilient modulus- The elastic modulus based on
the recoverable strain under repeated loads is called
the resilient modulus MR =σd/σr .
19. Characteristic of Pavement material
(Continue ….)
26/10/201619
The following material properties are consider for
both flexible and rigid pavements.
When pavements are considered as linear elastic, the
elastic moduli and poisson ratio are specified.
If the elastic modulus of a material varies with the time of
loading, then the resilient modulus is selected.
20. Design procedures for flexible pavements:
26/10/201620
Design Procedures
Empirical Design
Mechanistic-
Empirical Design
Mechanistic
Design
IRC:37-2012 is based on Mechanistic-Empirical
Design
21. Mechanistic-empirical design
26/10/201621
1. It can be used for both existing pavement
rehabilitation and new pavement construction
2. It can accommodate changing load types
3. It uses material proportion that relates
better with actual pavement performance
4. It provides more reliable performance
predictions
22. Failures of flexible pavements:
26/10/201622
Different types of failure encountered in flexible
pavements are as follow.
1. Alligator cracking or Map cracking (Fatigue)
2. Consolidation of pavement layers (Rutting)
3. Shear failure cracking
4. Longitudinal cracking
5. Frost heaving
6. Lack of binding to the lower course
7. Reflection cracking
8. Formation of waves and corrugation
9. Bleeding
10. Pumping
23. 1. ALLIGATOR OR MAP CRACKING
(FATIGUE CRACKING)
26/10/201623
Followings are the primary causes of
this type of failure.
Relative movement of pavement
layer material
Repeated application of heavy
wheel loads
Swelling or shrinkage of subgrade
or other layers due to moisture
variation
24. 2. CONSOLIDATION OF PAVEMENT
LAYERS (RUTTING)
26/10/201624
Formation of ruts falls in this
type of failure.
A rut is a depression or
groove worn into a road by
the travel of wheels.
This type of failure is caused
due to following reasons.
•Repeated application of
load along the same
wheel path resulting
longitudinal ruts.
•Wearing of the surface
course along the wheel
path resulting shallow
ruts.
25. 3. SHEAR FAILURE CRACKING:
26/10/201625
Shear failure causes
upheaval of pavement
material by forming a
fracture or cracking.
Followings are the primary
causes of shear failure
cracking.
•Excessive wheel loading
•Low shearing resistance of
pavement mixture
26. 4. LONGITUDINAL CRACKING:
26/10/201626
This types of cracks extents to the
full thickness of pavement.
The following are the primary
causes of longitudinal cracking.
Differential volume changes in
subgrade soil
Settlement of fill materials
Sliding of side slopes
27. 5. FROST HEAVING:
26/10/201627
Frost heaving causes
upheaval of localized
portion of a pavement.
The extent of frost
heaving depends upon
the ground water table
and climatic condition.
28. 6. LACK OF BINDING WITH LOWER LAYER
(POTHOLES & SLIPPAGE)
26/10/201628
When there is lack of
binding between surface
course and underlying
layer, some portion of
surface course looses up
materials creating patches
and potholes.
Slippage cracking is one
form of this type of failure.
Lack of prime coat or tack
coat in between two layers
is the primary reason
behind this type of failure.
29. 7. REFLECTION CRACKING:
26/10/201629
This type of failure
occurs, when
bituminous surface
course is laid over the
existing cement
concrete pavement
with some cracks. This
crack is reflected in
the same pattern on
bituminous surface.
30. 8. FORMATION OF WAVES &
CORRUGATION :
26/10/201630
Transverse
undulations appear
at regular intervals
due to the unstable
surface course
caused by stop-and-
go traffic.
31. 9. BLEEDING:
26/10/201631
Excess bituminous
binder occurring on the
pavement surface
causes bleeding.
Bleeding causes a shiny,
glass-like, reflective
surface that may be
tacky to the touch.
Usually found in the
wheel paths.
33. FAILURES OF FLEXIBLE PAVEMENTS
DESIGN CONSIDERATION:
26/10/201633
The design of flexible pavement as per IRC is
based on two major failure that are, fatigue
cracking and rutting failure.
34. IRC METHOD OF DESIGN OF FLEXIBLE
PAVEMENTS (IRC: 37-2012)
26/10/201634
1. IRC:37-1970
based on California Bearing Ratio (CBR) of subgrade
Traffic in terms of commercial vehicles (more than 3
tonnes laden weight)
2. IRC:37-1984
based on California Bearing Ratio (CBR) of subgrade
Design traffic was considered in terms of cumulative
number of equivalent standard axle load of 80 kN in
millions of standard axles (msa)
Design charts were provided for traffic up to 30 msa using
an empirical approach.
.
35. Continue ….
26/10/201635
3. IRC:37-2001
based on Mechanistic-Empirical method
Pavements were required to be designed for traffic as
high as 150 msa.
The limiting rutting is recommended as 20 mm in 20 per
cent of the length for design traffic
4. IRC:37-2012
based on Mechanistic-Empirical method
The limiting rutting is recommended as 20 mm in 20 per
cent of the length for design traffic up to 30 msa and 10
per cent of the length for the design traffic beyond
36. Guidelines for Design by IRC: 37: 2012
26/10/201636
Design Traffic:
The recommended method considers design traffic
in terms of the cumulative number of standard axles
(80 kN) to be carried by the pavement during the
design life.
Only the number of commercial vehicles having
gross vehicle weight of 30 kN or more and their axle-
loading is considered for the purpose of design of
pavement.
Assessment of the present day average traffic
should be based on seven-day-24-hour count made
in accordance with IRC: 9-1972 "Traffic Census on
Non-Urban Roads".
37. Traffic growth rate (r):
26/10/201637
Estimated by Analyzing:
The past trends of traffic growth,
Change in demand of Traffic by factors like specific
development, Land use changes etc.
If the data for the annual growth rate of commercial
vehicles is not available or if it is less than 5 per
cent, a growth rate of 5 per cent should be used
(IRC:SP:84-2009).
38. Design life (n)
26/10/201638
The design life is defined in terms of the cumulative
number of standard axles in msa that can be carried
before a major strengthening, rehabilitation or
capacity augmentation of the pavement is
necessary.
Depending upon road type, Design traffic is ranges
from 10 to 15 years.
39. Vehicle damage factor (VDF)
26/10/201639
It is defined as equivalent number of standard axles
per commercial vehicle.
The Vehicle Damage Factor (VDF) is a multiplier to
convert the number of commercial vehicles of
different axle loads and axle configuration into the
number of repetitions of standard axle load of
magnitude 80 kN.
43. Lane distribution factor
26/10/201643
Distribution of commercial traffic in each direction
and in each lane is required for determining the total
equivalent standard axle load applications to be
considered in the design.
In the absence of adequate and conclusive data, the
following distribution may be assumed until more
reliable data on placement of commercial vehicles
on the carriageway lanes are available:
45. Computation of Design traffic:
26/10/201645
The design traffic in terms of the cumulative number
of standard axles to be carried during the design life
of the road should be computed using the following
equation:
46. Sub-grade
26/10/201646
Requirements of CBR: Sub grade is made up of in-
situ material, select soil or stabilized soil.
Compacted to a minimum of 97% of laboratory dry
density achieved with heavy compaction.
Minimum CBR of 8% for traffic > 450 CVPD
CBR can also be determined from Dynamic Cone
Penetrometer (60º cone) by ..
Log10 CBR = 2.465-1.12log10 N
Where, N = mm/blow
47. Sub-grade (Continue…)
26/10/201647
Where different types of soils are used in sub grade
minimum 6 to 8 average value for each type is required.
90th percentile for high volume and 80th percentile for
other category of road is adopted as design CBR .
Maximum permissible variation
Where variation is more average CBR should be average
of 6 samples and not three.
48. Effective CBR
26/10/201648
Where there is significant difference between the
CBRs of the select sub grade and embankment
soils, the design should be based on effective CBR.
The effective CBR of the subgrade can be
determined from Fig.
49. Lab procedure for CBR calculation:
26/10/201649
The test must always be performed on remoulded
samples of soils in the laboratory.
The pavement thickness should be based on 4-day
soaked CBR value of the soil, remoulded at
placement density and moisture content ascertained
from the compaction curve.
In areas with rainfall less than 1000 mm, four day
soaking is too severe a condition for well protected
sub-grade with thick bituminous layer and the
strength of the sub-grade soil may be
underestimated.
50. Continue ….
26/10/201650
If data is available for moisture variation in the
existing in-service pavements of a region in different
seasons, molding moisture content for the CBR test
can be based on field data.
Wherever possible the test specimens should be
prepared by static compaction. Alternatively dynamic
compaction may also be used.
51. Resilient Modulus:
26/10/201651
Resilient modulus is the measure of its elastic
behavior determined from recoverable deformation
in the laboratory tests.
The modulus is an important parameter for design
and the performance of a pavement.
The relation between resilient modulus and the
effective CBR is given as:
52. Continue ….
26/10/201652
The CBR of the sub-grade should be determined as
per IS: 2720 (Part 16) (36) at the most critical
moisture conditions likely to occur at site.
53. Principle of pavement design:
26/10/201653
Pavement Model:
Modeled as linear elastic
multilayer structure.
Stress Analysis is based on
IITPave software
Critical parameters for
analysis are
1. Tensile strain at the bottom
of bituminous layer
2. Vertical sub-grade strain at
the top of sub-grade.
Failure of pavement is
considered due to cracking
and rutting
54. Check for Fatigue:
26/10/201654
Micro cracks at the bottom of bituminous layer are
developed with every load repetition
These cracks goes on expending till they propagate
to the surface due to the large load repetition
In these guidelines, cracking in 20 per cent area has
been considered for traffic up to 30 msa and 10 per
cent for traffic beyond that.
55. Check for Fatigue (Continue….)
26/10/201655
Two fatigue equations developed based on
performance data collected during various study are
Nf= 2.21 * 10-04x [1/εt]3.89* [1/MR]0.854 (80 %
reliability)…(a)
Nf= 0.711 * 10-04x [1/εt]3.89* [1/MR]0.854 (90 %
reliability)...(b)
Where,
Nf= fatigue life in number of standard axles,
εt= Maximum Tensile strain at the bottom of the
bituminous layer, and
MR= resilient modulus of the bituminous layer.
Equation for 90% reliability implies that only 10% of
the pavement area will have more than 20% cracks.
56. Check for Fatigue (Continue….)
26/10/201656
To consider the effect of volume of the bitumen and air
voids equation (b) is modified as follows
Nf =0.5161 * C * 10-04 x [1/ εt]3.89 * [1/MR]0.854………(c)
Va= per cent volume of air void and Vb= per cent volume
of bitumen in a given volume of bituminous mix.
Nf= fatigue life, єt= maximum tensile strain at the bottom
of DBM.
MR= Resilient modulus of bituminous mix.
For traffic < 30 msa consider equation (a); For traffic >
30msa equation (c) is recommened.
57. Check for Rutting:
26/10/201657
Rutting is the permanent deformation in pavement
usually occurring longitudinally along the wheel path.
Causes –
1. Deformation in sub grade /non-bituminous layer
2. Secondary compaction and shear deformation of
bituminous layer
Limiting value
20 mm in 20% length for upto 30 msa
20 mm in 10% length for > 30 msa
Rutting affects the serviceability of pavement.
58. Rutting (Continue …)
26/10/201658
Based on various studies the two equation develops
are;
N = 4.1656 x 10-08[1/εv]4.5337 (80 per cent reliability)
N = 1.41x 10-8x [1/εv]4.5337 (90 per cent reliability)
Where,
N = Number of cumulative standard axles, and
εv= Vertical strain in the sub-grade
59. Pavement composition as per IRC:
26/10/201659
A flexible pavement covered in these guidelines
consists of different layers as shown in figure;
60. SUB-BASE LAYER
26/10/201660
UNBOUND SUB-BASE LAYER
Sub-base materials may consist of natural sand,
moorum, gravel, laterite, kankar, brick metal,
crushed stone, crushed slag
Sub-base materials passing 425 micron sieve when
tested in accordance with IS:2720 (Part 5) should
have liquid limit and plasticity index of not more than
25 and 6 respectively.
61. SUB-BASE LAYER(Unbound SB Continue…)
26/10/201661
When coarse graded sub-base is used as a drainage
layer, Los Angeles abrasion < 40
Required permeability; fines passing 0.075 mm
should be less than 2 per cent.
Sub-base is constructed in two layers, the lower
layer forms the separation/filter layer to prevent
intrusion of subgrade soil into the pavement and the
upper GSB forms the drainage layer to drain away
any water
Resilient modulus (MR) for granular sub-base
MRgsb = 0.2 h0.45 * MR subgrade
Where, h = thickness of sub-base layer in mm
62. SUB-BASE LAYER
26/10/201662
Bound Sub base
Material for bound sub-base may consist of soil,
aggregate or soil aggregate mixture modified with
chemical stabilizers such as cement, lime-flyash.
The drainage layer of the sub-base may consist of
coarse graded aggregates bound with about 2 per
cent cement while retaining the permeability.
Drainage and separation layers are essential when
water is likely to enter into pavements from the
shoulder, median or through the cracks in surface
layer.
63. SUB-BASE LAYER(Unbound SB Continue…)
26/10/201663
Strength Parameter:
Elastic Modulus E of bound sub-bases is
Ecgsb = 1000 * UCS
Where UCS = 28 day strength of the
cementitious granular material
64. BASE LAYER
26/10/201664
UNBOUND BASE LAYER
Base layer may consist of wet mix macadam, water
bound macadam, crusher run macadam, reclaimed
concrete etc.
Resilient modulus of the granular base is given as..
MR granular = 0.2 * h0.45 MR subgrade
Where h = thickness of granular sub-base and base,
mm
Poisson's ratio of granular bases and sub-bases
is recommended as 0.35.
65. BASE LAYER(Continue..)
26/10/201665
CEMENTITIOUS BASES :
Cemented base layers may consist of aggregates or
soils or both stabilized with chemical stabilizers, to
give a minimum strength of 4.5 to 7 MPa in 7/28
days.
Default values of modulus of rupture are
recommended for cementitious bases (MEPDG).
Cementitious stabilized aggregates - 1.40 MPa
Lime—flyash-soil - 1.05 MPa
Soil cement - 0.70 MPa
Poisson's ration of the cemented layers may be
taken as 0.25.
66. Criteria for selecting Bitumen grade.
26/10/201666
The recommended resilient modulus values of the
bituminous materials with different binders are:
67. Continue …..
26/10/201667
The Poisson’s ratio of bituminous layer depends upon the
pavement temperature and a value of 0.35 is
recommended for temperature up to 35°C and value of
0.50 for higher temperatures.
Higher viscosity of bituminous binders, which can be
achieved either by using higher viscosity grade bitumen
or modified bitumen will improve both fatigue and rutting
behavior of mixes as compared to mixes with normal
bitumen.
Fatigue equation at any pavement temperature from
20°C to 40°C can be evaluated by substituting the
appropriate value of the resilient modulus of the
bituminous mix, air void and volume of bitumen.
Catalogue of designs has been worked out for a
temperature of 35°C.
68. Drainage Layer
26/10/201668
Improvement of drainage can significantly reduce the
magnitude of seasonal heave. The desirable
requirements are:
(a). Provision must be made for the lateral drainage of the
pavement structural section. The granular sub-base/base
should accordingly be extended across the shoulders
(b). No standing water should be allowed on either side of
the road embankment.
(c). A minimum height of1 m between the subgrade level
and the highest water level
71. Drainage Layer(Continue…)
26/10/201671
Criteria to be satisfied:
The filter/separation layer should satisfy the following
criteria:
To prevent entry of soil particles into the drainage layer:
D85 means the size of sieve that allows 85 per cent by
weight of the material to pass through it.
Similar is the meaning of D50 and D15.
73. What is design ?
26/10/201673
Design of pavement includes deciding
the number of layers, its composition and
thickness for selected material, to
support traffic load safely without failure.
74. Various cases in design.
26/10/201674
The flexible pavement with different combinations of
traffic loads and material properties.
1) Granular base and Granular sub-base.
2) Cementitious base and sub-base with agg.
Interlayer.
3) Cementitious base and sub-base with SAMI.
4) RAP agg. Over cemented sub-base
5) Cemented base and Granular sub-base
75. Problem statement.
26/10/201675
Design the pavement for construction of a
new flexible pavement with the following data:
Four lanes divided National Highway.
Design life is 15 years.
76. Data collection
26/10/201676
Material properties :
California Bearing Ratio (CBR)
Resilient Modulus (MR)
Modulus of Elasticity (E)
Poisson’s ratio (µ)
77. Material properties
26/10/201677
CBR : The CBR values are calculated after
every kilometre on selected stretch of 10 km
having the same type of soil. Suppose the
values obtained are: 3.8, 2.8, 4.5, 3.9, 4.2, 2.9,
4.7, 4.3, 4.0 and 4.6%. Based on the
collected data the design CBR (90th percentile
CBR) is calculated as below:
78. Solution :
26/10/201678
Arrange in ascending order : 2.8, 2.9, 3.8, 3.9, 4.0,
4.2, 4.3, 4.5, 4.6 and 4.7.
Calculate the percentage greater than equal of the
value as follows:
For CBR of 3.8, percentage of values greater than
equal to 3.8 = (8/10) x100 = 80%
Similarly for 2.8 % is 100%, 4.5% CBR is 80% and
so on.
Now a plot is made between Percentages of values
greater than equal to the CBR values versus the
CBR as follows.
81. Poisson’s ratio
26/10/201681
Poisson’s ratio µ is define as the ratio of lateral strain
(ɛl) to the axial strain (ɛa), caused by load parallel to
the axis along which ɛa is measured.
It is found that for most of the pavement structures,
the influence of µ value is normally small.
For most of cement treated materials (soil cement,
cement treated base, lean concrete and PCC), the
value of µ normally lies between 0.10 and 0.25.
Unbound granular material lie between 0.2 and 0.5
and those for bituminous mixes range from 0.35 to
0.50
82. Elastic modulus
26/10/201682
Elastic moduli of various pavement materials
are obtained either through tests or through
the recommendations available in the
guidelines.
Repeated flexure or indirect tensile tests are
carried out to determine the dynamic modulus
Ed of bituminous mixes.
83. Resilient modulus
26/10/201683
Resilient modulus is the measure of its elastic
behaviour determined from recoverable deformation
in the laboratory tests.
The behaviour of the subgrade is essentially elastic
under the transient traffic loading with negligible
permanent deformation in a single pass.
This can be determined in the laboratory by
conducting tests.
84. Calculation of MR for Sub-grade.
26/10/201684
The resilient modulus is calculated as follow;
MR (Mpa) = 10 x CBR …………. For CBR 5
= 17.6 x CBR0.64 ………For CBR > 5
(From equation 5.2, Page no. 12, IRC: 37: 2012)
85. Calculation of MR for Granular base and
sub-base.
26/10/201685
The resilient modulus is calculated as follow;
MRgsb = 0.20 x h0.45 x MR subgrade
h = Thickness of sub-base layer in mm, …… sub-
base,
= Cumulative thickness of Base layer and Sub-
base layer in mm ... for base
86. Traffic count
26/10/201686
Assessment of average daily traffic should be normally
based on 7 day-24hr count made in accordance with
IRC: 9 “Traffic census on non-urban roads”.
Classify traffic into different categories such as two
wheelers, three wheelers, passenger cars, trucks etc.
But only commercial vehicle with laden weight > 3 tonne
is taken into consideration of design.
Commercial vehicles are further categorised as single
axle single wheel, single axel dual wheel, Tandem axle
dual wheel and Tridem axle dual wheel.
Where no traffic count data is available, data from roads
of similar classification and importance may be used to
predict the design traffic
87. Calculation of Design factor
26/10/201687
1) Design Traffic,
2) Axle load survey,
3) Vehicle Damage Factor
4) Lane Distribution Factor
88. Design Traffic:
26/10/201688
Initial traffic after construction in terms of number of
Commercial Vehicles per day (CVPD).
Traffic growth rate during the design life in
percentage.
Design life in number of years.
Spectrum of axle loads.
Vehicle Damage Factor (VDF).
Distribution of commercial traffic over the
carriageway.
89. Calculation of Design traffic:
26/10/201689
For our case the number of heavy commercial vehicle
per day is taken as 7 day average for 24 hour count
comes to be 2792 vehicle per day as per the last count.
i. e. P = 2792 cvpd, r = 7 %, and x = 10 years
A = 2792 (1+0.07)10 = 5000 cvpd.
RESULT: Traffic in the year of completion of construction
is 5000 cvpd in both the directions.
90. Axle load survey :
26/10/201690
Required for VDF calculation and Fatigue damage
analysis of cementitious base.
The axle load spectrum is formulated by considering
10 kN, 20 kN and 30 kN intervals for single, tandem
and tridem axle respectively.
RESULT: As per study the percentage of Single,
Tandom and Tridom axle are 45%, 45% and 10%
respectively
92. Vehicle damage factor
26/10/201692
The formula to calculate VDF is given as follows:
W1, W2, ….. are the mean values of the various axle load
groups.
V1, V2, …. are the respective traffic volumes.
Ws is the standard axle load.
Standard axle load for Single axle, Tandem axle and
Tridem axle is 80 KN, 148 KN and 224 KN as per
IRC: 37:2012 (Page 7)
RESULT: The VDF for Single axle load, Tandem axle
load and Tridem axle load is 4.11, 8.37 and 7.51.
93. Vehicle Damage factor (Continue.)
26/10/201693
Were sufficient information on axle loads are not
available or the small size of project does not
warrant an axle load survey the default values of
VDF may be adopted as given in the table given
below.
94. Lane distribution factor.
26/10/201694
Distribution of commercial traffic in each direction
and in each lane is required for determining the total
equivalent standard axle load applications to be
considered in the design.
Single lane road : Total vehicle in both direction.
Two lane single carriage way : 50% of total vehicle in
both direction.
Four lane single carriage way : 40% of total vehicle
in both direction.
Dual carriage way: Two lane 75%, Three lane 60%,
Four lane 45% of number of CV in each direction.
95. Lane distribution factor (Continue….)
26/10/201695
RESULT: In the present design problem we are
given to design a four lane divided highway,
therefore the Lane distribution factor is 75 percent of
number of commercial vehicle in each direction.
96. Million standard axle
26/10/201696
The design traffic is calculated in terms of cumulative
number of standard axle of 80 kN carried during the
design life of the road.
r = 7.5 %,
n = 20 yr. ( Expressway and Urban roads), 15 yr (NH
and SH), In this problem we have to design National
highway take n as 15 years,
A is 5000cvpd in both direction and 2500 in one
direction
97. Calculation of Million std. axle.
26/10/201697
Single axle load (N1): 45 percent vehicles are of single
axle.
A : 0.45 x 2500 = 1125, F : 4.11
N1 = 33.06 x 106 = 33.06 msa
Tandem axle load (N2): 45 percent vehicles are of
tandem axle.
A : 0.45 x 2500 = 1125, F : 8. 37
N2 = 67.33 x 106 = 67.33 msa
Tridem axle load (N3): 10 percent vehicles are of tridem
axle.
A : 0.10 x 2500 = 250, F : 7.51
98. Calculation of Million std. axle. (Continue…)
26/10/201698
Total msa (N1+N2+N3)
= 33.06 + 67.33 + 13.42
= 113.81 ̴ 150 msa (Aprox.)
RESULT: The cumulative million standard axles to
be consider for design is 150 msa.
100. Determination of thickness for Case 1
26/10/2016100
The thickness of various layers is determined with
the help pavement design catalogue given in IRC:
37: 2012 from page 26 to 28, for various values of
effective CBR.
101. Determination of thickness for Case 1
(Continue ….)
26/10/2016101
RESULT:
For design traffic of 150msa and CBR of 7%
Thickness of subbase (GSB) is 230 mm,
Thickness of base (G. Base) is 250 mm,
Thickness of Dense Bitumen macadam (DBM) is 140
mm,
Thickness of Bituminous concrete (BC) is 50 mm
102. Case 2 : Bituminous pavement with
cemented base and cemented sub-base
with aggregate inter layer of 100mm
26/10/2016102
104. Determination of thickness for case 2.
26/10/2016104
RESULT:
For design traffic of 150msa and CBR of 7%
Thickness of Cementitious sub-base (CT Subbase)
is 250 mm,
Thickness of Cementitious base (CT Base) is 120
mm, Aggregate interlayer is 100mm
Thickness of Dense Bitumen macadam (DBM) is 50
mm
Thickness of Bituminous concrete (BC) is 50 mm are
Obtained by interpolating the thickness of CBR 5%
and 10%.
105. Calculation of Resilient Modulus (MR) for
case 2
26/10/2016105
MR subgrade = 17.6 x CBR0.64 = 17.6 x 70.64 = 61.15
Mpa.
MR Bituminous layer = 3000 Mpa (From table 7.1
Resilienent Modulus of Bituminous Mixes, page 23,
IRC: 37: 2012)
Pavement composition for 90 per cent Reliability is
BC + DBM = 100 mm,
Aggregate interlayer = 100 mm (MR = 450 MPa),
Cemented base = 120 mm (E = 5000 MPa),
Cemented subbase = 250 mm (E = 600 Mpa)
106. Case 3 : Bituminous pavement with
cemented base and cemented sub-base with
SAMI layer over cemented base.
26/10/2016106
108. Determination of thickness for Case 3
26/10/2016108
RESULT:
Design traffic of 150 msa and CBR of 7%
thickness of Cementitious sub-base (CT Subbase) is
250 mm,
Thickness of Cementitious base (CT Base) is 165
mm,
Thickness of Dense Bitumen macadam (DBM) is 50
mm
Thickness of Bituminous concrete (BC) is 50 mm
are
obtained by interpolating the thickness of CBR 5%
and 10%.
109. Case 4 Bituminous pavement with base of
fresh aggregate or RAP treated with foamed
bitumen/ Bitumen emulsion and cemented
sub-base
26/10/2016109
111. Determination of thickness for case 4
26/10/2016111
RESULT:
Design traffic of 150 msa and CBR of 7%
Thickness of Cementitious sub-base (CT Subbase) is
250 mm,
Thickness of Treater reclaimed aspalt pavement (Treated
RAP) is 180 mm,
Thickness of Dense Bitumen macadam (DBM) is 50 mm
Thickness of Bituminous concrete (BC) is 50 mm are
Obtained by interpolating the thickness of CBR 5% and
10%.
Instead of RAP base of fresh aggregates treated with
bitumen emulsion/ foamed bitumen can be used to obtain
stronger base.
112. Case 5 : Bituminous pavement with
cemented base and granular sub-base with
100mm WMM layer over cemented base:
26/10/2016112
114. Determination of thickness for case 5
26/10/2016114
RESULT:
Design traffic of 150 msa and CBR of 7%
Thickness of Granulated Subbase (GSB) is 250 mm
Cementitious sub-base (CT Subbase) is 195 mm,
Thickness of aggregate layer is 100 mm, Thickness
of Dense Bitumen macadam (DBM) is 50 mm
Thickness of Bituminous concrete (BC) is 50 mm
Obtain by interpolating the thickness of CBR 5% and
10%.
The upper 100 mm of granular sub-base should be
open graded so that its permeability is about 300
mm/day or higher for quick removal of water entering
from surface.
115. Calculation of Resilient Modulus (MR) and
Modulus of Elasticity (E):
26/10/2016115
For traffic of 150 msa, Subgrade CBR 7%,
MR subgrade = 17.6 x CBR0.64 = 17.6 x 70.64 = 61.15
Mpa.
MR Bituminous layer = 3000 Mpa (From table 7.1
Resilienent Modulus of Bituminous Mixes, page 23,
IRC: 37: 2012)
MR Aggregate = 450 Mpa and
E of cemented base is 5000 MPa,
E Granular subbase = MR subgrade x 0.20 x h0.45
Where, h = Thickness of GSB = 250 mm
= 61.15 x 0.20 x 2500.45 = 146.72 Mpa.
116. Design check
26/10/2016116
To check the suitability of pavement design
discussed above we carry out checks, which ensure
safety against the failure of designed pavement.
The flexible pavement is checked for two types of
failures i.e. Rutting in pavement and Fatigue in
bottom layer of bituminous surfacing.
The following condition should be satisfied for the
design to be satisfactory
Design strain < Allowable strain
Allowable strain = Obtained by fatigue model and
rutting model
Design strain = IITpave software
117. Design of Drainage layer
26/10/2016117
Design a granular drainage layer for a four lane
heavy duty divided highway for an annual
precipitation of 1200 mm. Longitudinal slope = 3 per
cent, Camber = 2.5 percent.
Crack Infiltration Method
118. Continue ...
Depth of drainage layer = 450 mm (WMM 250mm
and Sub-base 200mm) By design.
Width of drainage layer : Calculate
AB = 8.5+1+2x0.45 = 10.4 m (1m unpave shoulder)
AC = 10.4 x(3/2) = 12.48 m.
AD = 16.24 m
(hypotenious of AB and AC)
Elevation drop :
Along AC: 12.48x3% = 0.374m
Along CD: 10.40x2.5% = 0.26m
Total drop = 0.634
26/10/2016118
120. Continue.
Amount of water infiltrated (Q);
Q = 0.083 x 1 x 16.24 = 1.35 Cub.meter/ day.
Compare with
Q = KIA
A = Area of cress section = 1 x 0.1 = 0.1 sq.m
K = Coeff of permeability (Unknown)
I = Hydraulic gradient (0.039)
1.35 = K x 0.039 x 0.1
K = 346.62 m/day
This value of K is useful for deciding gradation.
26/10/2016120
122. Recommendation
26/10/2016122
Specifications should be modified according to local
condition. In wet climate wearing course should be
impermeable.
long duration and low intensity rainfall causes more
damage as compare with rainfall of small duration
and more density.
If DBM and SDBC/BC are designed properly (4% air
voids and protected shoulder) impermeably can be
ensure.
Adequate provision for sub-surface drainage prevent
pavement damage.
123. Recommendations.
Thickness charts with BC/ SDBC are valid for all
rainfall area.
For pavement carrying heavy traffic wearing course
laid over WBM shows better performance.
For low traffic (upto 5 msa) bitumen surfacing with
two coats is found to be suitable.
26/10/2016123
124. Conclusion
26/10/2016124
Time to time revisions of code provision are needed
keeping in view changes in traffic pattern and
development of new technologies. Further with the
gain of experience in the design as well as
construction procedure of flexible pavement have
demanded certain changes.
Hence by considering the above factors IRC: 37:
2012 includes some conceptual changes in the
design of flexible pavement such as inclusion of
Resilience moduli and consideration of strain in
design.
125. Conclusion .
26/10/2016125
This code also encourages the use IIT pave software
which is newly recommended.
Since the use of semi-mechanistic approach, the
design is not only based on the experience but it
also gives parameters (strain parameter) to check
the obtained design.
Solution to the above pavement design problem
shows that the thickness design varies with the
variation in various factors.
126. References
26/10/2016126
[1] IRC: 37: 2012, “Guidelines for Design of Flexible
pavement”, second revision.
[2] IRC: 37: 2001, “Tentative guidelines for Design of
Flexible pavement”