This document discusses various types of materials used in pavement design and their properties. It provides an overview of different soil classification systems including AASHTO, Unified Soil Classification System (USCS), and Federal Aviation Administration (FAA) systems. These systems classify soils based on gradation tests and Atterberg limits. The document also describes various material models used in pavement design including linear elastic, viscoelastic, nonlinear, and plastic models. Key material properties needed for pavement design are also outlined.

1. 1
Material Properties
Mansoura University - Faculty of Engineering – Public Works Engineering Dept.
Material Types
• Unbound (soil)
• Natural (i.e., subgrade)
• Select (i.e., subbase, base)
• Asphalt concrete
• Portland cement concrete
• Stabilized materials
• Cement stabilized
• Bituminous stabilized
• Bedrock
• Recycled
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Material Properties Needed for Design
• Pavement response model material inputs
• Modulus (stiffness)
• Poisson’s ratio
• Materials-related pavement distress criteria
• Permanent deformation resistance
• Fatigue resistance
• Strength
• Other material properties
• Density
• Permeability
• Thermal expansion coefficient
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Material Models
(Yoder and Witczak, 1974)

2. 2
Mansoura University - Faculty of Engineering – Public Works Engineering Dept.
Material Models
• Linear elasticity
• Asphalt
• Stabilized layers
• Unbound layers
• Linear viscoelasticity
• Asphalt
• Nonlinear (all materials, to some extent)
• Nonlinear elasticity
• Plasticity
• Nonlinear viscoelasticity
• Viscoplasticity
Mansoura University - Faculty of Engineering – Public Works Engineering Dept.
Soil Classification
Systems
Mansoura University - Faculty of Engineering – Public Works Engineering Dept.
Soil Classification
 The separation of soil into classes or
groups each having similar characteristics
and potentially similar behaviour
 Few simple (routine) tests are used to
classify soils.
Gradation (Sieve Analysis)
Atterberg Limits (LL & PL)
Mansoura University - Faculty of Engineering – Public Works Engineering Dept.
Soil Classification Systems
• MIT
• AASHTO
• USCS
• FAA

3. 3
Mansoura University - Faculty of Engineering – Public Works Engineering Dept.
MIT Classification
Material Size (mm)
Boulder > 60
Gravel
Fine 2 – 6
Medium 6 – 20
Coarse 20 – 60
Sand
Fine 0.06 – 0.2
Medium 0.2 – 0.6
Coarse 0.6 – 2
Silt
Fine 0.002 – 0.006
Medium 0.006 – 0.02
Coarse 0.02 – 0.06
Clay < 0.002
Mansoura University - Faculty of Engineering – Public Works Engineering Dept.
AASHTO Classification
• AASHTO: American Association of State
Highways and Transportation Officials
• Used mainly for subgrade rating for
highway purposes.
• Requires:
• Gradation
• LL
• PI
AASHTO Classification
**ForA-7-5 soil PI ≤ LL-30, ForA-7-6 soil PI > LL-30
#10
#40
#200
Granular Material (%P#200 ≤ 35%) Fine Grained Material
(%P#200 > 35%)
Characteristics of
Material P#40
Mansoura University - Faculty of Engineering – Public Works Engineering Dept.
Notes
• NP = Non Plastic (No Clay)
• The First Group to Fit the Date from the Left is the Correct
AASHTO Classification.
• The Placement of A-3 before A-2 is necessary for the left to
right process and does not indicate superiority of A-3 over
A-2
**ForA-7-5 soil PI ≤ LL-30
**ForA-7-6 soil PI > LL-30

4. 4
Mansoura University - Faculty of Engineering – Public Works Engineering Dept.
Group Index (GI)
• GI is used to evaluate soils within one
group.
• GI = 0.2 a + 0.005 a.c + 0.01 b.d (0 to 20)
a = %P#200 – 35 (0 to 40)
b = %P#200 – 15 (0 to 40)
c = LL – 40 (0 to 20)
d = PI – 10 (0 to 20)
• GI to the nearest whole number (integer)
• High GI  low quality material
• EX: A-7-6(5), A-7-6(18)
Mansoura University - Faculty of Engineering – Public Works Engineering Dept.
USCS Classification
• USCS: Unified Soil Classification
System
• Used mainly for geotechnical purposes
• Requires:
• Gradation
• LL
• PI
Mansoura University - Faculty of Engineering – Public Works Engineering Dept.
USCS Classification
Soil Symbol Property Symbol
Gravel G Well Graded W
Sand S Poor Graded P
Silt M High LL (High Plasticity) H
Clay C Low LL (Low Plasticity) L
Peat Pt Clay C
Organic
soil
O Silt M
EX: SC  Clayey Sand EX: Dual Symbol: SP-SM
GW  Well Graded Gravel poorly graded sand
CL  Clay with low plasticity with silt
Mansoura University - Faculty of Engineering – Public Works Engineering Dept.
Computing CU and CC
Coefficient of Uniformity
Coefficient of Curvature
High Values Indicate Well-
Graded Soil
Values Between 1-3 Indicate
Well-Graded Soil
10
60
D
D
CU 
6010
2
30
DD
D
CC



5. 5
Mansoura University - Faculty of Engineering – Public Works Engineering Dept.
A-Line Chart
Separates Clays and Silts
0
10
20
30
40
50
60
0 10 20 30 40 50 60 70 80 90 100
LIQUID LIMIT
PLASTICITYINDEX
CH
CL
ML
MH
CL-ML
ML &
OL
OH &
MH
Mansoura University - Faculty of Engineering – Public Works Engineering Dept.
USCS Classification
Mansoura University - Faculty of Engineering – Public Works Engineering Dept.
USCS Classification (Coarse-Grained)
Coarse-
Grained
Soils
%P#200
≤50%
% P #4 < 50%
(Gravel, G)
Less than
5% Fines
Cu>4, Cc = (1-3) G
W
Not satisfying GW GP
More than
12% Fines
A.L. Below A-Line or PI<4 GM
PI>7& A.L. Above A-Line GC
% P #4 > 50%
(Sand, S)
Less than
5% Fines
Cu>6, Cc = (1-3) SW
Not satisfying SW SP
More than
12% Fines
A.L. Below A-Line or PI<4 SM
PI>7& Above A-Line SC
Mansoura University - Faculty of Engineering – Public Works Engineering Dept.
USCS Classification (Fine-Grained)
Fine-
Grained
Soils
%P#200>
50%
LL<50%
ML
CL
OL
LL>50%
MH
CH
OH
Highly Organic Soils Pt
0
10
20
30
40
50
60
0 20 40 60 80 100
LIQUID LIMIT
PLASTICITYINDEX
CH
CL
ML
MH
CL-ML
OH & MH
ML
&
OL

6. 6
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USCSDual Symbols
For the following conditions a dual symbol
should be used:
a) 5% < %P#200 < 12%
The first symbol is indicative of the gradation (W or
P), the second symbol is indicative of the fines.
EX: SP-SM poorly graded sand with silt
b) Fine grained soils within the shaded zone in the A-
line chart (PI between 4 and 7, LL between 12 and
25).
EX: CL-CM, Silty clay with Low LL
Mansoura University - Faculty of Engineering – Public Works Engineering Dept.
Comparison between the AASHTO and
Unified Systems
• Both systems are based on the texture and
plasticity of the soil.
• Both systems divide the soils into two
major categories: Coarse grained and Fine
grained based on %P#200 SI sieve.
• AASHTO:
• %P#200 < 35%  Coarse grained
• %P#200 > 35%  Fine grained
• Unified:
• %P#200 < 50%  Coarse grained
• %P#200 > 50%  Fine grained
Mansoura University - Faculty of Engineering – Public Works Engineering Dept.
Comparison between the AASHTO and
Unified Systems (Cont’d)
• AASHTO: #10 sieve separates gravels and
sand
• Unified: #4 sieve separates gravels and
sand
• AASHTO : There is no organic soil
• Unified : There is organic soil
• AASHTO: gravely and sandy soils are not
clearly separated
• Unified: gravely and sandy soils are clearly
separated
Mansoura University - Faculty of Engineering – Public Works Engineering Dept. (NCHRP 1-37A. 1999)

7. 7
Mansoura University - Faculty of Engineering – Public Works Engineering Dept. (Das, 1990) Mansoura University - Faculty of Engineering – Public Works Engineering Dept.
FAA Classification
• FAA: Federal Aviation Administration
• Used mainly for soil classification for airport
construction.
• Requires:
• Gradation
• LL
• PI
FAA Classification (Yoder & Witczak 1975)
Soil
Group
% R#10 %P#10,
R#60
%P#60,
R#270
%P#270 LL PI
E-1 0-45 40+ 60- 15- 25- 6-
E-2 0-45 15+ 85- 25- 25- 6-
E-3 0-45 - - 25- 25- 6-
E-4 0-45 - - 35- 35- 10-
E-5 0-55 - - 45- 40- 15-
E-6 0-55 - - 45+ 40- 10-
E-7 0-55 - - 45+ 50- 10-30
E-8 0-55 - - 45+ 60- 15-40
E-9 0-55 - - 45+ 40+ 30-
E-10 0-55 - - 45+ 70- 20-50
E-11 0-55 - - 45+ 80- 30+
E-12 0-55 - - 45+ 80+ -
E-13 Muck and Peat – Field Examination
Mansoura University - Faculty of Engineering – Public Works Engineering Dept.
FAA Classification Chart for Fine-Grained
Soils
80
70
60
50
40
30
20
10
0 10 20 30 40 50 10 60 70
E-12
E-9 E-10
E-8
E-7
E-6
Plasticity Index
liquidLimit
E-11
100
90
(Yoder & Witczak 1975)

8. 8
Mansoura University - Faculty of Engineering – Public Works Engineering Dept.
It is Hard to be
an engineer!