Recent Advances in Pavement Deisgn of Flexoble Papenent by IRC:37.pdf

Prof. R. Srinivasa Kumar
Osmania university
Hyderabad
[email protected]

1. Recent Advancement in
Flexible Pavement Design -AN OVERVIEW ON IRC:37



- Prof. R. Srinivasa Kumar
[email protected]
[email protected]
Osmania University
Hyderabad, India.
1

2. 2
Reliable Suitable
Thickness
Strategy Economical
Subgrade
Traffic
Analysis
Materials
Climate
Factors

3. Factors considered for Material Testing
Traffic
Characteristics
Material
Characteristics
Environmental
Effects
Evaluation &
Condition
PMS &
Rehabilitation
Identify Design
Features
3

4. 4
Types of Pavement Design
1. Empirical Methods
Group-1: GI, FAA 1945
Group-2: CBR, Plate
Load test etc.
Group-3: AASHTO-
1972, 81, 86 (Regres
2.Theoretical or
Analytical Methods
Burmister (1943,1945)
3. M-E Methods

2008-AASHTO guide
IRC:37-2018,
IRC:58-2015

5. 5
List of A Few Empirical Design Methods
Test on subgrade soil Design Input Design Methods
1. California Bearing
Ratio (CBR)
CBR Value
California State Highway Dept.(1928), US
Corps of Engineers (1958), British Revised
CBR, Wyoming CBR, National Asphalt
Pavement Association, NAPA (Foster, 1965),
National Crushed Stone Association, (NCSA,
1972), TAI (1970),
IRC:37-1970 Method & NAASRA (1979).
2. Cone Penetration Penetration Value North Dakota Cone Method
3. Plate Load
Deflection of Plate or
Modulus of subgrade
reaction (k)
US Navy Method based on Burmister’s Elastic
Theory for Airfield Pavements and Canadian
Dept. of Transport or McLeod Method
4. Hveem
Stabilometer and
Cohesiometer
R and C-values
respectively
California Resistance Value Method (1948)
5. Triaxial
Compression
Elastic Modulus value
Triaxial Method (1910), which was modified
by Kansas State Highway Dept.
(A semi-arbitrary method which partly
comprises theoretical consideration)

6. INDIAN Guidelines for the Design of
Flexible Pavements by IRC:37
Source:IRC:37-2018
6
Courtesy: IRC

7. Timeline of Flexible Pavement
•IRC:37-1970: Empirical Design (based TRRL)
•Shell Method (1963 Emp. & 1977 M-E
+CTB
), 1982 M-E)
•Asphalt Institute (1982 M-E
+Emulsons
, 1991 M-E)
•South Africa-National Institute for Trans. & Road Research, 1982
•IRC:37-1984: 1
st
-Revision (Emp.)
•Austroads, (1992 M-E)
•AASHTO method (1993)-Serviceability
EMP
•LCPC, France, (1997 M-E)
•IRC:37-2001: 2
nd
– M-E Design
TF
•AASHTO MEPDG 2008
•IRC:SP:20-2002: PMGSY & IRC:SP:72-2007: Rural Roads
•IRC:37-2012: 3
rd
– M-E Design
TF+, Composite-Pave
•IRC:37-2018: 4
th
– M-E Design
7

8. First Guidelines: IRC:37-1970
•Adapted based on International Practice (California
State Highway Dept., & TRRL) of Empirical Design
with suitable adjustments
•Design Traffic based on CV (>=3ton);[email protected]%
•Categories of Commercial Traffic:A – E (450-1500 CVPD)
•Subgrade is characterized by CBR value
•Total Thickness: CBR Vs. Traffic range (A-E)
•Individual layer thicknesses can be estimated from
the CBR value of the underlying layer
•Limitations: climatic conditions based on pavement
temperatures, vehicle categories, axle load
spectrum, no-lanes and materials Char. of different
layers
8

9. First Guidelines: IRC:37-1970
(No msa concept)
9
Courtesy: IRC

10. First Revision: IRC:37-1984
(Semi-empirical)
•Design Traffic: ESAL (80kN), axle loads
•AASHO –Axle load- Equivalency Factors
•VDF values recommended for diff. cases
•Default VDF=3: Thick Pavements, Plain terrain,
>1500CVPD
•LDF
•ESAL (8160kg): Axle spectrum considered
•[email protected]%
•Only for New pavement-designs
10
Courtesy: IRC

11. First Revision: IRC:37-1984
•Thickness design chart for csa (upto 30msa) of diff.
CBRs (2-10%)


•Capping on subgrade: 500mm,
•Sub=base: min. CBR20% (2msa), 30% (>2msa)

11
Courtesy: IRC

12. First Revision: IRC:37-1984
CBR
12
Courtesy: IRC

13. First Revision: IRC:37-1984
•continued for design traffic upto 1500 CVD
•However, modified CBR curves for 10.2 T single
axle legal limits were used instead of 8.16 T and
thickness was increased by 10 - 20%. 13
Courtesy: IRC

14. First Revision: IRC:37-1984
•Equivalent Thickness Conversion factors:
BM: 1.5
DBM:2.0 •GSB-Drainage Consideration
14
Courtesy: IRC

15. The M-E Era started in INDIA
from 2001 onwards….
15
Courtesy: IRC

16. M-E Approach of pavement Design
Mechanistic- Part
•Multi layered structure
•Each layer characterized
by its thickness, modulus
of elasticity and
Poisson’s ratio.

•Stresses, strains &
deflections at critical
locations within the
pavement structure
under traffic loading
Empirical Part
•These calculated critical
strains were correlated
with pavement
performance indicators:
Cracking & Rutting for a
design life by empirically
derived equations known
as distress models/
performance prediction
models based on past
experience, field obs. and
laboratory results.
•Pavement Performance
Prediction PPP-Model.
Structural Response Model
16

17. The Mechanistic-Empirical (M-E)
Design Approach
17

18. M-E Designs Started from
•Inspired from:
•First International Conference on the
Structural Design of Asphalt
Pavements
•Ann Arber, Michigan, USA, 1962.
18

19. 19
M-E Pavement Design Method - IRC Design Method
Subgrade (E
n, μ
n)
Granular Sub-base (E
3, μ
3)
Granular Base (E
2, μ
2)
Bituminous Layer (E
1, μ
1)
310 mm
ε
t
ε
z
Tyres
h
1
h
2
h
3
1.Dorman, 1962
2.Saal and Pell, University of Nottingham with
Shell Laboratories, 1960
3. Monismith et al. University of California, 1961

20. FP design based on M–E principles
20
•.COmparing Mix and Pavement StructureS
(COMPASS) by the CROW working group.
•South African mechanistic design method (SAMDM)
(Theyse et el. 1996 and 1997).
•CARE (Road and Hydraulic Engineering Institute,
Deft) (CROW Report D06-06).
•French Design Manual, LCPC, Paris (CROW Report
D06-06).
•Shell Pavement Design Manual (Shell 1985).
•CROW Design Procedure for Thin Asphalt
Pavements: (CROW Report D06-06).
•The Asphalt Institute Method, MS-1, USA (TAI 1991).
AUSTROADS Pavement Design Guide, Australia
(AUSTROADS 1992).

21. FP design based on M–E principles
21
•Washington State DoT(WSDOT) Pavement Guide
(WSDOT 1995; Mahoney and Pierce 1996).
•Minnesota DoT (MnDOT) mechanistic–empirical
flexible pavement design (1998).
•AASHTO M–E Design Guide for New and
Rehabilitated Pavement Structures (NCHRP, 2003).
•Key features: Finite element analysis, load spectra,
roughness evaluation in terms of IRI and reliability in
life-cycle cost assessment.
•Analytical design methods developed at IIT
Kharagpur, India. (Sudhakar 1993 and Animesh
1998).
•IRC:37-2001.

22. IRC:37-2001
•Design Approach:
•3 Layer structure
•Strains @ critical locations
•FPAVE- Linear Elastic Model
•Based on R-56 (MORTH project)
•150 msa
•Mix Specifications introduced
•E-values of DBM (with 60/70) used for
determination of allowable strains in BT layer
•E-values: subgrade, GSB and SubBase given

22
Courtesy: IRC

23. IRC:37-2001 Contd.,

•Design Approach:
•Fatigue criterion: calibrated at an AAPT of 35 °C
for BC (80/100 bitumen). Generalised for all grades
of bitumen for a temp. 20 - 40 °C:
•N
f = 2.21× 10
–4
×(1/ ε
t)
3.89
× (1/E
bit)
0.854

N
f = No of csa to cause 20% cracked surface
The DBM with 60/70 used
•Rutting criterion: Allowable rut depth = 20 mm.
N
R = 4.1656× 10
–8
×(1/ ε
z)
4.5337

N
R = No. of csa to produce rut depth of 20 mm.
ε
z

= Vertical compressive subgrade strain (×10
–6
)

23
Courtesy: IRC

24. IRC:37-2001 Contd.,

•Empirical Eq. used:
E
subgrade (MPa) = 10 × CBR for CBR ≤ 5 %
E
subgrade (MPa) = 17.6 × (CBR)
0.64
for CBR > 5 %

E
granular layer (MPa) = E
subgrade × 0.2 × (h
gran)
0.45

Min. Thickness:
GSB: up to 10 msa is 150 mm (CBR >20%)
exceeding 10 msa is 200 mm (CBR>30
Gran.Base:
up to 2 msa is 225 mm (CBR >20%)
exceeding 2 msa is 250 mm (CBR>30%)

24
Courtesy: IRC

25. IRC:37-2001 Contd.,

•Thickness charts:
•1-150msa
•CBR (2-10%)
25
Courtesy: IRC

26. 26


Internal Drainage
Cracked Bit. Surface
Base Course
Sub-base Course
Sub-grade
Intrusion of fines
takes place
Undesirable

27. Internal Drainage:
Horizontal movement of moisture
in Sib-base
27


Sub-base Course
Desirable Condition

28. Internal Drainage:
Check for Intrusion of Subgrade Fines into Sub-base = ?
IRC:SP:50-2013 IRC:SP:42-2014 MORTH, 2013
28
Courtesy: IRC

29. 29
WMM-Base

Sub-base

Sub-grade

Bituminous
The basic ingredients of both mixes are same but the
differences lies in % of fines in DL & FL of GSB mix.
Sub-base
GSB
Upper GSB
Drainage Layer
Lower GSB
Filter Layer

30. GSB gradings Recommended by
IRC:37-2012, MORTH-2013, AASHTO(1993)
30
Courtesy: IRC

31. To prevent Intrusion of Fines
GSB Grades as per IRC:37 &
MORTH 2013
•MORTH GSB grades: I, II, III, IV, V and VI = 6
Select:
Upper GSB as DL: V & VI
Lower GSP as Filter/Separation Layer: III & IV

The DL should be tested for permeability and
gradation may be altered
31

32. IRC:37-2001 Contd.,
Elastic Modulus (MPa) of Bituminous Mixes
32
Courtesy: IRC

33. IRC:37-2001 Contd.,
Criteria for selection of Grade of Bitumen
33
Courtesy: IRC

34. Observations on IRC:37-2001
•Sufficient thickness of the sub-base/Gran. recommended
in 2001 to stand under construction traffic.
•Rutting in Subgrade & Gran.
•The data on bituminous layers (1980-90) were not very
thick in India and the rutting took place in the subgrade
and the granular layers only. (90% Reliability given in
2012)
•Providing large thickness of gran. layer does not reduce
in thickness of bituminous layer from fatigue
considerations
•Rutting in Bit. layer was to be taken care of by selecting
stiffer binder and mix design (2012 onwards…).
•50% less rut depth found by VG 40 as compared with
VG 30 (MEPDG.., >2000CVPD & >40
0
C).
34

35. Observations on IRC:37-2001
•Fatigue Resistance of Bituminous Layers
•Laboratory tests & field performance indicate that fatigue
life of a bituminous layer depends on bitumen content &
VG of a mix (C factor given in 2012)
•Softer grade (VG30) gave unstable mix with higher
bitumen content if exposed to construction traffic.
•Bituminous layer thickness >150 mm, the temperature of
the bottom DBM is lower than the top; little chance of
rutting in DBM, if the air void = 3%.
•Higher bitumen (having 0.5% - 0.6%) higher
bitumen(VG40) content in DBM makes the mix resistant
to stripping & impermeable and air void = 3% (CRRI)
•Tensile strains near edge of tyres will be higher due to
high temp. (TDC considered from 2012 onwards…)
•Polymer and CRMB: 2-10 times higher live than normal.

35

36. IRC:37-2012 (3
rd
Revision)
•IRC:37-2001, also applicable for upto 30
msa, used bitumen gr. VG 30, with 80%
reliability.
•IRC:37-2012 recommends VG 40 with
traffic beyond 30 msa with 90% reliability.
•Alternate materials: cementitious & RAP
considered to analysis using the software
IITPAVE, a modified version of FPAVE.
•Test values are based on National
Standards of Australia, South Africa and
AASHTO(MEPDG) and India/CRRI.
•
36

37. Grades of Bitumen (IS:73-2006)
•Min. Dynamic viscosity at 60
0
C
37

38. 38
Polymer-Modified Bitumen
•Polymers mixed with bitumen to improve strength:











In India, 3-types are widely used:
1.Poly-ethylene,
2.Vnyl-acetate
3.sSyrene-Butadine-Styrene.
•The above are used for preparation of modified bitumens and emulsions.
Elastomers
Induce elasticity & stiffness
properties to bitumen
1. Styrene Isoprene Styrene,
2. Styrene Butadiene Styrene,
Ethylene/propylene
3. Styrene Butadiene,
4. Poly-butadiene,
5. Some types of Rubbers
Plastomers
Induce plasticity or viscosity or stiffness to
bitumen.
1.Poly-ethylene,
2.Ethylene Vinyl Acetate
3.Ethylene Butyl Acrylate
4.Linear low-density Polyethylene
(LLDPE)
Types of Polymers
(Used for paving)

39. Advantages of Polymer Modified Bitumen
Increases
Softening Point
Increases
Viscosity & Shear
Resistance
Retards Oxidation
Reduce Rutting
Reduction Bitumen
by upto 10%
Extend upto 50% of
service period
39

40. IRC:37-2012 (3
rd
Revision)
•CASE-II
•Cement Treated: Sub-base & Base
•Sub-base with its upper 100 mm graded
as permeable “Drainage Layer” (infiltration
@ ≥300 m/day)
•Treated Base course should have a min.
UCC of 4.5 - 7 MPa in 7/28 days.
•Material Char. are from AASHTO 2002
(MEPDG).

40

41. IRC:37-2012 (3
rd
Revision)
•CASE-III
•Cement Treated: Sub-base & Base

41

42. IRC:37-2012 (3
rd
Revision)
•Min. Traffic growth @ 5%
•Design Life:
–NH& SH: 15 yr.
–Ex& Urban : >20 yr.
–Very High Vol roads: 200 msa
–Other : 10-15 yr.
• in-situ CBR of subgrade soil
(ASTM-D6951-09)
–Log
10CBR = 2.465 – 1.12 log
10N
60
o

42

43. Single
Wheel
(4000 kN)
Tyre
Pressure =
0.56 MPa
Embankment (CBR = 4%)
Subgrade-borrowed Soil
Layer (CBR = 12%)
500 mm
Tyre contact radius
a = 150.8 mm
12%
8.0%
4%
How to Compute Effective Subgrade CBR due to Capping Layer?
As per IRC:37-2012
Capping layer: 8% min.
designed traffic ≥ 450 CVPD
43

44. IRC:37-2012 (3
rd
Revision)
•Fatigue Model:
•cracking 20% area for traffic up to 30 msa
•10% for beyond traffic.




<30msa, VG30,35
o
C
2001
>30msa, VG40
Courtesy: IRC
44

45. IRC:37-2012 (3
rd
Revision)
•Rutting Model:
•limiting rutting: as 20 mm in 20 % of the
length for design traffic up to 30 msa
•10 % of the length for beyond.



•Charts: 2-150msa; CBR:3-15%
80%
2001
90% Reliability
Courtesy: IRC
45

46. 1970
EMP
•Upto
1500
CVPD
•Design
curves
1984
EMP

•Upto 30
msa
•80kN
•Design
curves
2001
M-E
•R-6 & R-
56
MoRTH
•FPAVE
•Upto
150msa
2012
M-E

•Catalog VI
cases
•IITPAVE
•RAP
•CTB, CTSB
•80% & 90%
Reliabty.
•VG-grades

Timeline of improvements in IRC:37
2018
M-E

•Upto 300 msa
•Fine tuned
from feedback
•Better
Bit./Binder/ CT
Mixes
•E
Bit-Values
•Min. Thickness
of CTB & CTSB
•Effective CBR
•Provision for
Geo-synthetics
46

47. 2018 & 2012
Perpetual Pavements (≥ 300msa)
•AI, MS-4, 7
th
Ed. (Endurance Limits)
•Tensile strain in Bit. layer < 70 micro strain
•Comp. strain in Subgrage layer < 200 micro strain


•INDIA
•AAPT: 35
0
C
•Endurance Limits: 80 & 200 micro strain
• Only top surface need maintenance….
Courtesy: IRC
47

48. Example 10.6, Page:347
Check adequacy of WMM = 200mm ? Assumed Value
Proposed WMM as GSB thickness = 200mm
Effective modulus of combined capping layer with subgrade = 72 MPa
Given Pavement with Standard Axle Load
48

49. General Design-
Steps
Inputs: Select Criterion,
layers No. & Thickness, E, µ,
h, P, Nf
By Eqn’s Calculate: Allowable Strains in
1.ε
v in Subgrade top
Compute: Actual Strains in
1.ε
v in Subgrade top
Run
NO
YES
Finalize Base-Thickness
Check
?
Actual < Allowable
Strain
49

50. What is new in IRC:37-2018
Criteria for selection of Grade of Bitumen 2001
2012
2018
Courtesy: IRC
50

51. What is new in IRC:37-2018
Criteria for selection of Grade of Bitumen
2012
2018
Courtesy: IRC
51

52. What is new in IRC:37-2018
1984 2012
2018
Courtesy: IRC
52

53. What is new in IRC:37-2018
Courtesy: IRC


» 2012
»



2018

53

54. Modes of Failures considered for
Mechanistic-Empirical Design
Failure
Modes
Fatigue
Failure
Rutting
Failure
54

55. Failure
Modes
Fatigue
Failure
Rutting
Failure
N
f
= 1.6064 × C× 10
–4
× (1/ ε
t
)
3.89
× (1/E
bit
)
0.854
80% reliability

N
f
= 0.5161 × C× 10
–4
× (1/ ε
t
)
3.89
× (1/E
bit
)
0.854
90% reliability


Where,
N
f
= No. of cumulative 80 kN-standard axles to cause 20% and more cracked
surface area
ε
t

= Tensile strain at bottom fibre of the bituminous layer (×10
–6
) and
E
bit
= Resilient modulus of the bituminous surfacing (MPa).



V
be
= Volume of effective bitumen binder in the bituminous layer (%)
V
a
= Volume of air voids in the bituminous layer (%)
Fatigue Cracking of Asphalt
Pavement Courtesy: IRC
55

56. Subgrade Rutting Criteria
Rut Depth ≥ 20mm
Failure Rutting Condition
N
R
= 4.1656 × 10
–8
×(1/ ε
z
)
4.5337
80 % reliability < 20msa

N
R
= 1.41 × 10
–8
×(1/
ε
z
)
4.5337
90 % reliability ≥ 20 msa

where,
N
R
= No. of cumulative standard axles to produce rut depth of 20 mm

ε
z

= Vertical compressive sub-grade strain (×10
–6
)
ε
z

Courtesy: IRC
56

57. CBT Failure
Criterion
Based on cum. Std. axle load
repetitions
estimated using VDF
Based on cum. Std. axle
load repetitions
estimated using Axle-Load
Spectrum
Fatigue Performance of Cement Treated Base (CTB)
IRC:37-2018
Courtesy: IRC
57

58. Fatigue Performance of Cement Treated Base (CTB)
IRC:37-2018
∑CFD(Single + Tandem + Tridem) ≤ 1.0?

Check :
Cumulative Fatigue Damage (CFD) in CTB

CBT Failure
Criterion
Based on cum. Std. axle load
repetitions
estimated using VDF
Based on cum. Std. axle
load repetitions
estimated using Axle-Load
Spectrum
Based on cum. Std. axle load
repetitions
estimated using Axle-Load
Spectrum
Courtesy: IRC
58

59. Single axle (80 kN = 80,000 kN)
Dual Wheels 310 mm
Tyre pressure =0.56 Mpa
Standard Axle Load - Single
155 mm 155 mm
59

60. • Traffic Surveys:
As per IRC:9-1972: 7 day 24 hours traffic count.
nc
rPA)1(
Laden weight ≥ 3 Ton
Traffic Growth Rate = 5.0% Min.
Design Period = 20 yr. Min., Ex, NH, SH
=15 yr. Other
Traffic
Design Traffic:
60

61. Sub-grade Requirements
•Min. CBR = 5%, for traffic > 450 CVPD
•Capping Layer 500 mm thick

•DCP:

61

62. E
subgrade
(MPa) = 10 × CBR for lab-CBR ≤ 5 %

E
subgrade
(MPa) = 17.6 × (CBR)
0.64
for lab-CBR > 5 %
Sub-grade Requirements

(Conversion : CBR → E
Subgrade)
Poisson's Ratio: µ = 0.35
Courtesy: IRC
62

63. Sub-grade Requirements

Effective Subgrade Modulus with Capping Layer: E
Subgrade
Effective CBR = ?
Effective E
subgrade =
=
63

64. Sub-base
Granular Sub-base (GSB)

Min. Thickness:
Filter Layer :100 mm
Drainage layer :100 mm

Drainage-cum-filter Layer
= 150 mm




µ = 0.35

Cemented Treated
Sub-base (CTSB)


E
CTSB :600 MPa
If UCS:1.5-3MPa

E
CTSB :400 MPa
If UCS:-0.75-1.5 MPa


µ = 0.25
E
granular (MPa):
= E
Effective-subgrade × 0.2 × (h
gran)
0.45

64

65. Base
Granular Base (GB)
WMM, WBM

Min. Thickness: 150 mm
Cemented Treated
Base (CTB)

Min. Thickness: 100 mm

E
CTB : 5000 MPa
UCS:4.5-7MPa
µ = 0.25
E
granular :
= E
Effective-subgrade × 0.2 × (h
both)
0.45

E
granular placed on CTSB:
= 300 Mpa, Natural Gravel
= 350 Mpa ,Crished Roack.

Crack Relief Layer:
Min. Thickness (WMM)
= 100 mm

E
crack Relief : 450 Mpa
µ = 0.35
Reclaimed Asphalt Pavement
RAP:
Min. Thickness = 100 mm

E
RAP: 800 Mpa
µ = 0.35
65

66. General
Design-Steps
Inputs: Select Criterion,
layers No. & Thicknesses,
E, µ, h, P, Nf
By Eqn’s Calculate: Allowable Strains in
1.ε
t in Bituminous Layer
2.ε
v in Subgrade top
Compute: Actual Strains in
1.ε
t in Bituminous
/ CBT Layer
2.ε
v in Subgrade top
Run
NO
YES
Final Thicknesses
Check
?
Actual < Allowable
Strains
66

67. Example - Pavement Composition
Sub-grade (75 MPa), µ = 0.35
Granular Sub-Base
WMM
BC +DBM with
VG40
500 mm
140 mm
140 mm
640 mm
450 MPa, µ = 0.35
3000 MPa, µ = 0.35
Wheel
(20000
kN)
Tyre
Pressure
= 0.56
MPa
Wheel
(20000
kN)
Tyre
Pressure
=
0.56
MPa
80 kN of Std. Axle Load
Layer-1

Layer-2

Layer-3

155 mm
67

68. Run – IITPAVE Software
IRC:37-2018

Run

Courtesy: IRC
68

69. Example Input - IITPAVE
Sub-grade 75 Mpa, µ = 0.35
Granular Sub-Base
WMM
BC +DBM with VG40
500 mm
140 mm
140 mm
640 mm
450 MPa, µ = 0.35
3000 MPa, µ = 0.35

20000
kN

=
0.56

20000
kN

0.56
80 kN Axle Load
69

70. Example Output - IITPAVE
70

71. Example Output – IITPAVE
IRC:37-2018
Z= Depth from Surface R= Radial Dist. from Center of Tyre
Contact Area
SigmaZ= Vertical Stress R= Radial Dist. from Center of Tyre
Contact Area
Wheel
(20000
kN)
Tyre
Pressure
= 0.56
MPa
Wheel
(20000
kN)
Tyre
Pressure
= 0.56
MPa
155 mm
SigmaT= Tangential Stress SigmaR= Radial Stress TaoRZ= Shear Stress DispZ= Vertical Deflection epZ= Vertical Strain epT= Hor. Tensile Strain epR= Hor. Radial Strain
71

72. Max. of: epT & epR
Max. value of epT = 0.1283E-03 = 0.0001283
72

73. Max. epZ = ? In Subgrade
Max. value of epZ = 0.2053E-03 = 0.0002053
73

74. Challenges In Design- A look to the Future
•Well coordinated pavement performance
study and calibration of failure models in
India
•Air Temp & pavement Temp. across India
•As constructed Material Char. Data
•Guidelines do not constitute a rigid
standard
•Regional Designs suitable based on local
environment and pavement performance
in Hilly/Rolling/Coastal, Dry/Wet regions.
•LCC Analysis of the catalog-options
74

75. REFERENCES
IRC:37–1970, “Guidelines for the Design of Flexible Pavements”, First
published, The Indian Road Congress, New Delhi, September, 1970.
IRC:37–1984, “Guidelines for the Design of Flexible Pavements”, First
Revision, The Indian Road Congress, New Delhi, December, 1984.
IRC:37–2001, “Guidelines for the Design of Flexible Pavements”, Second
Revision, The Indian Road Congress, New Delhi, July, 2001.
IRC:37–2012, “Tentative Guidelines for the Design of Flexible Pavements”,
The Indian Road Congress, New Delhi, July, 2012.
IRC:37-2018, Guidelines
Garg, Sanjay, “Perpetual Flexible Pavements: Pavements of Future”, Journal
of the Indian Road Congress, Indian Roads Congress, Vol.73-1, 2012.
NCHRP, “Mechanistic-Empirical Design of New and Rehabilitated Pavement
Structures”, National Cooperative Highway Research Program, NCHRP
Project 1- 37A, National Research Council, Washington, D.C., 2004.
AASHTO-MEPDG, “Mechanistic-Empirical Pavement Design Guide, Interim
Edition: A Manual of Practice”, American Association of State Highway and
Transportation Officials, Washington, D.C., 2008.
R. Srinivasa Kumar, Pavement Design, Universities Press, 2012
R. Srinivasa Kumar, Transportation Engineering, Universities Press, 2018

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76. Books Authored by me Prof. R. Srinivasa Kumar
Osmania University, India
[email protected]
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