Matakuliah
Tahun : 2009
: S0753 – Teknik Jalan Raya
Pavement Design
Session 09-12

Contents
• Pavement Classification
• Load & Stress Distribution
•Load Analysis
•Pavement design for Rigid Pavement
•Pavement Design for Flexible Pavement
•Overlay
•Pavement Construction
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Pavement Classification
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Flexible Pavement
Those which are surfaced with
. These types of pavements are called "flexible" since the total pavement structure
or
due to traffic loads. A flexible pavement structure is generally
Bina Nusantara University composed of several layers of materials which can accommodate this "flexing".
5

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Flexible Pavement
6

Types of Flexible Pavement
Dense-graded
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Open-graded Gap-graded
Steve Muench

Rigid Pavement
Rigid pavements . Those which are surfaced with
These types of pavements are called
"rigid" because they are substantially
than flexible pavements due to PCC's high stiffness.
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Rigid Pavement
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Types of Rigid Pavement
• Jointed Plain Concrete Pavement (JPCP)
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Steve Muench

Types of Rigid Pavement
• Continuously Reinforced Concrete Pavement
(CRCP)
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Steve Muench
Photo from the Concrete Reinforcing Steel Institute

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JOINT
Rigid Pavement
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Composite
• Composite.
Those which are surfaced with portland cement concrete (PCC) and bituminous / asphalt materials as
construction
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Load & Stress Distribution
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Flexible Pavement
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Load & Stress Distribution
P ( Load )
Surface
Base
Subbase
Subgrade
Flexible Pavement
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Load & Stress Distribution
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Rigid Pavement
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Load & Stress Distribution
P ( Load )
Surface
Subbase or base
Subgrade
Rigid Pavement 17

Pavement Design
• Several typical methods
– Design catalog
– Empirical
• 1993 AASHTO method
– Mechanistic-empirical
• New AASHTO method (as yet unreleased)
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Design Catalog
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Example design catalog from the Washington Asphalt
Pavement Association (WAPA) for residential streets
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Empirical
• 1993 AASHTO Flexible Equation log
10
 
18

Z
R

S o

9 .
36
 log
10

SN

1


0 .
20
 log
10

PSI
4 .
5

1 .
5
0 .
40


1094
SN

1

5 .
19

2 .
32
 log
10
 
R

8 .
07
• 1993 AASHTO Rigid Equation log
10
 
18

Z
R

S o

7 .
35
 log
10

D

1


0 .
06

1


PSI log
10
4 .
5

1 .
5
1 .
624

10

D

1

8 .
46
7
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

4 .
22

0 .
32 p t

 log
10










    c d
 

1 .
132
215 .
63
 




D 0 .
75 
18 .
42
E c k
20
0 .
25
















Terms – Flexible
• W
18
(loading)
– Predicted number of ESALs over the pavement’s life.
• SN (structural number)
– Abstract number expressing structural strength
– SN = a
1
D
1
+ a
2
D
2 m
2
+ a
3
D
3 m
3
+ …
• ΔPSI (change in present serviceability index)
– Change in serviceability index over the useful pavement life
– Typically from 1.5 to 3.0
• M
R
(subgrade resilient modulus)
– Typically from 3,000 to 30,000 psi (10,000 psi is pretty good)
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Terms – Rigid
• D (slab depth)
– Abstract number expressing structural strength
– SN = a
1
D
1
+ a
2
D
2 m
2
+ a
3
D
3 m
3
+ …
• S’ c
(PCC modulus of rupture)
– A measure of PCC flexural strength
– Usually between 600 and 850 psi
• C d
(drainage coefficient)
– Relative loss of strength due to drainage characteristics and the total time it is exposed to near-saturated conditions
– Usually taken as 1.0
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Terms – Rigid
• J (load transfer coefficient)
– Accounts for load transfer efficiency
– Lower J-factors = better load transfer
– Between 3.8 (undoweled JPCP) and 2.3 (CRCP with tied shoulders)
• E c
(PCC elastic modulus)
– 4,000,000 psi is a good estimate
• k (modulus of subgrade reaction)
– Estimates the support of the PCC slab by the underlying layers
– Usually between 50 and 1000 psi/inch
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Pavement design for Rigid Pavement
The following input variables are needed for the AASHTO rigid pavement design procedure:
• ¨ 28-day Concrete Modulus of Rupture, psi ¨ 28-day
•Concrete Elastic Modulus, psi ¨
•Effective Modulus of Subbase/Subgrade Reaction, pci ¨
•Serviceability Indices
• ¨ Load Transfer Coefficient
• ¨ Drainage Coefficient ¨
•Overall Standard Deviation
• ¨ Reliability, % ¨
•Design Traffic,
•18-kip Equivalanet Single Axle Load (SEAL).
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Pavement design for Rigid Pavement
28-day Concrete Modulus of Rupture, Mr
The Mr of concrete is a measure of the
as determined by breaking concrete beam test specimens. A Mr of 620 psi at 28 days should be used with the current statewide specification for concrete pavement design. If the Engineer selects an alternate value for
Bina Nusantara University Mr, then it must be documented with an 25 explanation.

Pavement design for Rigid Pavement
Elastic modulus of concrete is an indication of concrete stiffness
. It varies depending on the coarse aggregate type used in the concrete. Although the value selected for pavement design could be different from the actual values, the elastic modulus does not have a significant effect on the computed slab thickness. A modulus of 5,000,000 psi should be used for pavement design. The use of a different value must be documented with an explanation.
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Pavement design for Rigid Pavement
Effective Modulus of Subbase/Subgrade
Reaction: k-value
The AASHTO guide allows pavement designers to take into account the structural benefits of all layers under the concrete slab. It also allows designers to consider the effect of loss of support of the underlying material due to erosion or deterioration.
The slab support is characterized by the modulus of subgrade/ sub base reaction, otherwise known as the k-value. It can be measured in the field by applying a
Bina Nusantara University 27 load equal to 10 psi on the subgrade/subbase combination using a 30-inch diameter steel plate. The k-

Pavement design for Rigid Pavement
Serviceability Indices
For concrete pavement design, the difference between the initial and terminal serviceability is an important factor. An initial serviceability value of 4.5 and a terminal serviceability value of 2.5 are to be used in the procedure, which results in a difference of 2.0. Different values, if used, must be documented and justified.
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Pavement design for Rigid Pavement
The load transfer coefficient is used to incorporate the effect of dowels, reinforcing steel, tied shoulders, and tied curb and gutter on
in the concrete slab due to traffic loading. The coefficients recommended in the
AASHTO Guide were based on findings from the AASHO
Road Test.
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Pavement design for Rigid Pavement
The drainage
of the sub base layers under the concrete slab. Good draining pavement structures do not give water the chance to saturate the subbase and subgrade; thus, pumping is not as likely to occur.
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Pavement design for Rigid Pavement
The reliability value represents a "
," with higher reliabilities representing pavement structures with less chance of failure.
The AASHTO Guide recommends values ranging from 50% to 99.9%, depending on the functional classification and the location (urban vs. rural) of the roadway. If the Engineer decides
Bina Nusantara University to use a different value, then it must be 31 documented and justified

Pavement design for Flexible Pavement
• Determine the desired terminal serviceability, p t
• Convert traffic volumes to number of equivalent 18-kip single axle loads (
)
• Determine the structural number,
• Determine the layer coefficients, a i
• Solve layer thickness equations for individual layer thickness
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Pavement design for Flexible Pavement
• Incorporates a degree of certainty into design process
• Ensures various design alternatives will last the analysis period
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Pavement design for Flexible Pavement

 Sub-base type
 Sub-base thickness
 Loss of support
 Depth to rigid foundation

i
• Use in layer thickness determination
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• Applies only to base and sub-base
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Flexible Pavement – Construction
Steve Muench

Fixed form
Rigid Pavement – Construction
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Steve Muench

Slipform
Rigid Pavement – Construction
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Steve Muench