Irc Flexible Pavement Design Notes
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Transcript of Irc Flexible Pavement Design Notes
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IRC Design Method for Flexible Pavements
Atul Narayan, S. P.
IIT Madras
September 6, 2015
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Outline
Introduction
Scope
Pavement Analysis
Pavement distress models
Subgrade Properties
Material Properties of Pavement Materials
Traffic
Design Catalogue
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Subordinate learning objectives
To analyze the stress-strain distribution in pavements for given
loading conditions.
To estimate pavement distresses based on stresses and
strains in pavement structure.
To explain the effect of mechanical properties on pavement
behavior and performance.
To analyze the stresses and distresses caused by vehicle
loading.
To estimate the expected volume of traffic in design life.
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Outline
Introduction
Scope
Pavement Analysis
Pavement distress models
Subgrade Properties
Material Properties of Pavement Materials
Traffic
Design Catalogue
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Scope
Source: IRC 37
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Scope (cont.)
Source: IRC 37
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Outline
Introduction
Scope
Pavement Analysis
Pavement distress models
Subgrade Properties
Material Properties of Pavement Materials
Traffic
Design Catalogue
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Pavement Analysis
Pavements are analyzed through layered elastic analysis.
All assumptions made in Burmisters layer theory are also
used here.
Pavement analysis was conducted using IITPAVE.
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Outline
Introduction
Scope
Pavement Analysis
Pavement distress models
Subgrade Properties
Material Properties of Pavement Materials
Traffic
Design Catalogue
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Distress ModelsFatigue:
Nf =2.21 104
3.89t M
0.854R
(for 80% reliability
) (1)
Nf =0.711 104
3.89t M
0.854R (for 90% reliability) (2)
Fatigue life considering effect of binder content and air void content
Nf =
0.5161C
10
4
3.89
t M
0.854
R (3)C =10M (4)
M =4.84 VbVb+Va
0.69 (5)
Rutting:
Nr =4.1656 108
4.5337v (for 80% reliability) (6)
Nf =1.41 108
4.5337v (for 90% reliability) (7)
There are fatigue life equations for cementitious layers as well
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Outline
Introduction
Scope
Pavement Analysis
Pavement distress models
Subgrade Properties
Material Properties of Pavement Materials
Traffic
Design Catalogue
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California Bearing Ratio
It is the pressure required to penetrate a standard cylindrical
sample of soil at 1.25 mm/min, expressed as a percentage of
the pressure required for a standard material (usually crushed
rock).
It can be determined in-situ using a Dynamic Cone
Penetrometer (600 cone) test (ASTM D6951-09)
log10 CBR =2.465 1.12 log10 N (8)
whereNis penetration in mm per blow.
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Resilient Modulus from CBR
MR =10CBR, CBR =5 (9)
MR =17.6(CBR)0.64, CBR >5 (10)whereMRis the resilient modulus in MPa.
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Distress ModelsFatigue:
Nf =2.21 104
3.89t M
0.854R
(for 80% reliability
) (11)
Nf =0.711 104
3
.89
t M0
.854
R (for 90% reliability) (12)Fatigue life considering effect of binder content and air void content
Nf =0.5161C 1043.89
t M0.854
R (13)
C =10M (14)
M =4.84 VbVb+Va
0.69 (15)
Rutting:
Nr =4.1656 108
4.5337v (for 80% reliability) (16)
Nf =1.41 108
4.5337v (for 90% reliability) (17)
There are fatigue life equations for cementitious layers as well
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Outline
Introduction
Scope
Pavement Analysis
Pavement distress models
Subgrade Properties
Material Properties of Pavement Materials
Traffic
Design Catalogue
S
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Subbase and Base
Granular Bases and Subbases:
MRgsb =0.2h0.45MRsubgrade (18)
Cementitious Granular Subbase:
Ecgsb =1000UCS (19)
whereUCS is the 28-day unconfined compressive strength
Unbound base:
MRgb
=0.2h0.45MRsubgrade
(20)
Poissons ratio of all base and subbase materials can be taken as
0.35
Bi i l
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Bituminous layers
Bituminous layers are classified into bituminous concrete (BC)
and dense bituminous macadam (DBM)
Resilient modulus can be determined by laboratory
experiments
Otherwise, typical values may be taken from the table below
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O tli
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Outline
Introduction
Scope
Pavement Analysis
Pavement distress models
Subgrade Properties
Material Properties of Pavement Materials
Traffic
Design Catalogue
Load Eq i alenc Factors
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Load Equivalency Factors
Single axle Singlewheel axle load in kN65
4
(21)
Single axle Dualwheel axle load in kN
80 4
(22)
Tandem axle Dualwheel axle load in kN148
4
(23)
Tridem axle Dualwheel
axle load in kN
224
4
(24)
Vehicle Damage Factors
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Vehicle Damage Factors
It is the same as truck factors used in AASHTO and Asphalt
Institute Design Method
VDF is the equivalent number of standard axles per
commercial vehicle (depends on commercial vehicle)
Sometimes, the average VDF of all commercial vehicles
(considering the volume of each) is also called VDF
VDF must be arrived by conducting axle load surveys
Axle Load Survey
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Axle Load Survey
Indicative VDF Values
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Indicative VDF Values
Design Traffic
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Design Traffic
N =365 (1 + r)n 1r
A D F (25)
where
Nis the cumulative number of standard axles in msa
ris the yearly growth rate of traffic
nis the design life of the pavement
Ais the initial number of Commercial Vehicles Per
Day (CVPD)
D is the Lane distribution factor
F is the average VDF
Lane Distribution Factor
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Lane Distribution Factor
Recomended Values:
Single-lane roads: 100%
Two-lane single carriageway roads: 50% Four-lane single carriageway roads: 40%
Dual carriageway roads: 75% of CVPD in each direction
Outline
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Outline
Introduction
Scope
Pavement Analysis
Pavement distress models
Subgrade Properties
Material Properties of Pavement Materials
Traffic
Design Catalogue
Design Charts
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Design ChartsChoice 1: Granular Base and Granular Subbase
Design Charts (cont )
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Design Charts (cont.)Choice 1: Granular Base and Granular Subbase
Design Charts
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Design ChartsChoice 2: Bituminous Pavements with Cemented Base and Cemented Subbase with Crack
Relief Interlayer of Aggregate
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Design Charts
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Design ChartsChoice 3: Cemented Base and Cemented Subbase with SAMI at the Interface of Cemented
Base and the Bituminous Layer
SAMI - Stress Absorbing Membrane Interlayer
Design Charts (cont.)
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g ( )Choice 3: Cemented Base and Cemented Subbase with SAMI at the Interface of Cemented
Base and the Bituminous Layer
Design Charts
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gChoice 4: Foamed Bitumen/Bitumen Emulsion Treated Rap/Aggregates Over Cemented
Subbase
Design Charts (cont.)
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g ( )Choice 4: Foamed Bitumen/Bitumen Emulsion Treated Rap/Aggregates Over Cemented
Subbase
Design Charts
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gChoice 5: Cemented Base and Granular Subbase with Crack Relief Layer of Aggregate
Interlayer Above the Cemented Base
Design Charts (cont.)
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Choice 5: Cemented Base and Granular Subbase with Crack Relief Layer of Aggregate
Interlayer Above the Cemented Base
Sample Calculations
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IRC Recommendations
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