Transcript MTO EMPIRICAL PAVEMENT DESIGN

The following presentation contains references to Tables
6.02 and 6.03, and “MTO Empirical Design Examples”, all
of which are posted under subsection 2.6 of the course
notes on the instructor’s website. Viewer discretion is
advised as some scenes contain material of a tabular
nature.
MTO EMPIRICAL
PAVEMENT
DESIGN
TABLE 6.03 a
STRUCTURAL DESIGN GUIDELINES FOR FLEXIBLE PAVEMENTS
- KING'S HIGHWAYS AND FREEWAYS
(After: "Pavement Design and Rehabilitation Manual", 1990)
TABLE 6.03 b
STRUCTURAL DESIGN GUIDELINES FOR FLEXIBLE PAVEMENTS
- SECONDARY HIGHWAYS
(After: "Pavement Design and Rehabilitation Manual", 1990)
Subgrade Material
Subgrade Material
Gravels
Range of
Pavement
and Sands
SANDS AND SILTS
Lacustrine
Varved &
AADT
Structure
Suitable as
Percent Passing No. 200 Sieve
Clays
Leda Clays
Elements
Gran. Borrow
<40%
40 - 55%
>55%
HM
130
130
130
130
130
130
B
150 - 250
150
150
150
150
150
> 4000
3000 -
SB
---
300 - 450
450 - 600
600 - 800
450
450 - 1100
GBE
410 - 510
610 - 710
710 - 810
810 - 945
710
710 - 1145
HM
120 - 130
120 - 130
120 - 130
120 - 130
120 - 130
120 - 130
B
150 - 250
150
150
150
150
150
Gravels
Range of
Pavement
and Sands
SANDS AND SILTS
Lacustrine
Varved &
AADT
Structure
Suitable as
Percent Passing No. 200 Sieve
Clays
Leda Clays
Elements
Gran. Borrow
<40%
40 - 55%
HM
90
90
90
90
90
90
2000 -
B
150
150
150
150
150
150
3000
SB**
---
300
450
600
450
800
GBE
330
530
630
730
630
865
HM
50
50
50
50
50
50
1500 -
B
150
150
150
150
150
150
2000
SB**
---
250
300
450
300
450(300 - 600)
GBE
250
415
450
550
450
550 (450 - 650)
>55%
ANY QUESTIONS?
4000
SB
---
300 - 450
450 - 600
600 - 800
450
450 - 1100
GBE
390 - 510
590 - 710
690 - 810
790 - 945
690 - 710
690 - 1145
HM
90
90
90
90
90
90
2000 -
B
150
150
150
150
150
150
CL
50
50
50
50
50
50
1000 -
B
150
150
150
150
150
150
3000
SB**
---
300
450
600
450
800
1500
SB**
---
250
300
450
300
450 (300 - 600)
GBE
330
530
630
730
630
865
GBE
240
405
440
540
450
540 (450 - 640)
HM
50
50
50
50
50
50
ST*
---
---
---
---
---
---
1000 -
B
150
150
150
150
150
150
500 -
B
150
150
150
150
150
150
2000
SB**
---
250
300
450
300
450 (300 - 600)
1000
SB**
---
150
250
300
250
350 (250 - 450)
GBE
250
415
450
550
450
550 (450 - 650)
GBE
150
250
315
350
315
385 (315 - 450)
HM
50
50
50
50
50
50
ST*
---
---
---
---
---
---
200 -
B
150
150
150
150
150
150
200 -
B
150
150
150
150
150
150
1000
SB**
---
150
250
300
250
300 (250 - 450)
500
SB**
---
150
250
300
250
300
GBE
250
350
415
450
415
450 (415 - 550)
GBE
150
250
315
350
315
350
Gravel
---
---
---
---
---
---
B
100
100
100
100
100
100
Notes: All AADT Volumes refer to Present Traffic
HM: Hot Mix Asphalt & Thickness (mm)
B: Base Thickness (mm)
< 200
SB**
---
150
250
300
250
300
GBE
100
200
265
300
265
300
SB: Subbase Thickness (mm)
GBE: Equivalent Thickness of Granular Base (mm)
( 1 mm HM = 2 mm B = 3 mm SB )
**: Proposed subbase thicknesses may be decreased or increased respectively
for harder or softer subgrade conditions in each category, except for
varved & leda clay subgrades where exceptionally large ranges are shown
Notes: All AADT Volumes refer to Present Traffic
HM: Hot Mix Asphalt & Thickness (mm)
B: Base Thickness (mm)
SB: Subbase Thickness (mm)
GBE: Equivalent Thickness of Granular Base (mm)
( 1 mm HM = 2 mm B = 3 mm SB = 1.11 mm CL)
CL: Cold Mixed, Cold Laid or Road Mixed Mulch
ST: Double Surface Treatment or Single Surface Treatment with Prime
*: Apply surface treatments 0.25 m wider that lane width
**: Proposed subbase thicknesses may be decreased or increased respectively
There are?
TABLE 6.03 b
TABLE
6.03 FOR
a
STRUCTURAL DESIGN GUIDELINES
FLEXIBLE PAVEMENTS
STRUCTURAL DESIGN
GUIDELINES
FOR
FLEXIBLE
PAVEMENTS
- SECONDARY HIGHWAYS
(After: "Pavement
and Rehabilitation Manual", 1990)
- KING'S HIGHWAYS
ANDDesign
FREEWAYS
Subgrades range from:STRONGEST
to
weakest
(After: "Pavement Design and Rehabilitation Manual", 1990)
Subgrade Material
Range of
AADT
Range
of
AADT

Same old
subgrades
OK, well here’s a little more…
You may have noticed that there were two
design charts:
Gravels
2000 -
3000
> 4000
1500 -
2000
3000 -
Pavement
and Sands
Gravels
Structure
Suitable
Pavement
and Sandsas
Elements
Gran.
Borrow
Structure
Suitable
as
HM
90
Elements Gran. Borrow
HMB
SB**
B
GBE
SB
HM
GBE
B
HM
SB**
B
GBE
SB
CL
GBE
B
HM
SB**
B
GBE
SB**
ST*
GBE
B
HM
SB**
BGBE
SB**
ST*
GBEB
HM
SB**
BGBE
SB**
Gravel
150
130
150 ---250
330
--410 -50
510
150
120 - 130
--150 - 250
250
--50
390 - 510
150
90
--150
240
----330
150
50
--150
150
----250
150
50
--150
150
------
Subgrade Material
SANDS AND SILTS
Percent
Passing
200 Sieve
SANDS
ANDNo.
SILTS
<40%
40
55%
>55%
Percent Passing No. 200 Sieve
90
<40%
150
130
300
150
530
300 - 450
610 -50
710
150
120 - 130
250
150
415
300 - 450
50
590 - 710
150
90
250
150
405
300
--530
150
50
150
150
250
250
--415
150
50
150
150
250
150
---
40 - 90
55%
150
130
450
150
630
450 - 600
710 -50
810
150
120 - 130
300
150
450
450 - 600
50
690 - 810
150
90
300
150
440
450
--630
150
50
250
150
315
300
--450
150
50
250
150
315
250
---
90
>55%
150
130
600
150
730
600 - 800
810 -50
945
150
120 - 130
450
150
550
600 - 800
50
790 - 945
150
90
450
150
540
600
--730
150
50
300
150
350
450
--550
150
50
300
150
350
300
---
Lacustrine
Clays
Lacustrine
Varved &
Leda Clays
Varved
&
Clays
Leda Clays
90
90
150
150
130
130
450
800
150
150
630
865
450
450 - 1100
50
710
710 - 50
1145
150
150
120 - 130
120 - 130
300
450(300 - 600)
150
150
450
550 (450 - 650)
450
450 - 1100
50
50
690 - 710
690 - 1145
150
150
90
90
300
450 (300 - 600)
150
150
450
540 (450 - 640)
450
800
----630
865
150
150
50
50
250
350 (250 - 450)
150
150
315
385 (315 - 450)
300
450 (300 - 600)
----450
550 (450
- 650)
150
150
50
50
250
300
150
150
315
350
250
300 (250---- 450)
--415
- 550)
100 450 (415
100
250
300
265
300
a) The first is for “Kings” Highways and Expressways
b) The second is for secondary highways
4000
1000 -
1500
2000 -
3000

500 -
So, a) has 5 levels (rows) of traffic (AADT)
which are different than the 6 for b)
The 6 columns for different subgrade
AADT>200
AADT<3000
vpd
vpdthe same for both
types are
Each cell has a conventional pavement
design
1000
1000 -
2000
200 -
500
200 -

1000
GBEB
250
350
415
100
100
100
SB**
--150
250
Notes: All AADT
refer to Present
GBE Volumes 100
200 Traffic265
HM: Hot Mix Asphalt & Thickness (mm)
< 200
450
100
300
300
B: Base
Thickness
(mm)
Notes: All AADT
Volumes
refer to
Present Traffic
SB:
Subbase
(mm)
HM:
Hot MixThickness
Asphalt &
Thickness (mm)

GBE:B:
Equivalent
Thickness
of Granular Base (mm)
Base Thickness
(mm)
( 1Subbase
mm HM =Thickness
2 mm B =(mm)
3 mm SB )
SB:
GBE:
Equivalent
Thickness
of Granular
Base
(mm)
**:
Proposed
subbase
thicknesses
may be
decreased
or increased respectively
( 1 harder
mm HM or
= softer
2 mm B subgrade
= 3 mm SB
= 1.11 mm in
CL)each category, except for
for
conditions
CL:
Cold Mixed,
or Road
Mixed
Mulch
varved
& leda Cold
clay Laid
subgrades
where
exceptionally
large ranges are shown
ST: Double Surface Treatment or Single Surface Treatment with Prime
*: Apply surface treatments 0.25 m wider that lane width
**: Proposed subbase thicknesses may be decreased or increased respectively
Example 1
A 2-lane county road is expected to have an
initial AADT of 1750 vpd and is to built
over a silty sand subgrade with 30% Passing
the No. 200 sieve.
a) Determine a conventional flexible pavement
design.
b) A couple of subsections require the use of
a deep strength design using cement
treated base and no subbase. Give the
appropriate layer thicknesses.
For a county road with
an AADT of 1750 vpd,
try Table 6.03b
• for AADT of 1750
use second row
• for silty sand with
30% passing no. 200
use second column
• And the winning
design is:
HM: 50 mm
B: 150 mm
SB: 250 mm
GBE: 415 mm
TABLE 6.03 b
STRUCTURAL DESIGN GUIDELINES FOR FLEXIBLE PAVEMENTS
- SECONDARY HIGHWAYS
(After: "Pavement Design and Rehabilitation Manual", 1990)
Subgrade Material
Gravels
Range of
Pavement
and Sands
SANDS AND SILTS
Lacustrine
Varved &
AADT
Structure
Suitable as
Percent Passing No. 200 Sieve
Clays
Leda Clays
Elements
Gran. Borrow
<40%
40 - 55%
HM
90
90
90
90
90
90
2000 -
B
150
150
150
150
150
150
3000
SB**
---
300
450
600
450
800
GBE
330
530
630
730
630
865
HM
50
50
50
50
50
50
1500 -
B
150
150
150
150
150
150
2000
SB**
---
250
300
450
300
450(300 - 600)
GBE
250
415
450
550
450
550 (450 - 650)
>55%
CL
50
50
50
50
50
50
1000 -
B
150
150
150
150
150
150
1500
SB**
---
250
300
450
300
450 (300 - 600)
GBE
240
405
440
540
450
540 (450 - 640)
ST*
---
---
---
---
---
---
500 -
B
150
150
150
150
150
150
1000
SB**
---
150
250
300
250
350 (250 - 450)
GBE
150
250
315
350
315
385 (315 - 450)
ST*
---
---
---
---
---
---
200 -
B
150
150
150
150
150
150
500
SB**
---
150
250
300
250
300
GBE
150
250
315
350
315
350
Gravel
---
---
---
---
---
---
B
100
100
100
100
100
100
< 200
SB**
---
150
250
300
250
300
GBE
100
200
265
300
265
300
Notes: All AADT Volumes refer to Present Traffic
HM: Hot Mix Asphalt & Thickness (mm)
B: Base Thickness (mm)
SB: Subbase Thickness (mm)
GBE: Equivalent Thickness of Granular Base (mm)
( 1 mm HM = 2 mm B = 3 mm SB = 1.11 mm CL)
CL: Cold Mixed, Cold Laid or Road Mixed Mulch
ST: Double Surface Treatment or Single Surface Treatment with Prime
*: Apply surface treatments 0.25 m wider that lane width
**: Proposed subbase thicknesses may be decreased or increased respectively
Lets
calculate
the GBE for
this design:
Granular Base
Equivalency
Layer
Thickness
(mm)
Equivalency
Factor
Hot Mix
50
2.00
100
Base
150
1.00
150
Subbase
250
0.67
167.5
Layer
Total Granular Base Equivalency (mm):
(mm)
417.5
 The tabulated GBE was 415.
 The tabulated GBE’s have been rounded to
the nearest 5 mm.
 Now on to part b)
Example 1 b)




Part b) calls for a deep
strength design
This would require that
the base and subbase be
replaced by a cement
treated base layer
(CTB)
The strength of the
base and subbase is
150 + 167.5 = 317.5 mm
of new Granular A
The Equivalency Factor
for CTB is… 1.80
TABLE 6.02
GRANULAR BASE EQUIVALENCY FACTORS
(After: "Pavement Design and Rehabilitation Manual", 1990)
NEW PROJECTS
Equivalency
Material
Factor
New or Recycled HL
Granular A in Base
Granular B in Subbase
Cement Treated Material in Subbase (with Gr. A base)
Cement Treated Material in Base (no subbase)
Bituminous Treated Material in Base (with Gr. A subbase)
Cold Mix
OGDL (Open Graded Drainage Layer)
2.00
1.00
0.67
1.40
1.80
1.50
1.80
1.00
RESURFACING PROJECTS
Equivalency
Material
Factor
Crushed RBM* (in base)
Bituminous Treated Crushed RBM*
Crushed RBM* Blended with New Granular A
Pulverized Bituminous Surface Mixed with Existing Base
Old HL
Old Granular Base
Old Granular Subbase
1.00
1.50
1.00
1.00
1.25
0.75
0.50
RECONSTRUCTION PROJECTS
Equivalency
Material
Factor
Granular A Layer
Old HL
Old Granular Base
Old Granular Subbase
1.00
1.00
0.60
0.40
Example 1 b)
 If the required thickness of CTB is TCTB,
then the GBE of the CTB is
1.80TCTB = 317.5 mm
 Solving, TCTB = 176.4
≈ 180 mm
 So the deep strength design would be:
Granular Base
Layer
Layer Thickness
(mm)
Equivalency
Factor
Equivalency (mm)
Hot Mix
50
2.00
100
CTB
180
1.80
324
Total Granular Base Equivalency (mm):
424
Example 2
A 12 km stretch of Highway 99 has 75
mm of hot mix over 180 mm of
granular base over 300 mm of granular
subbase. If the AADT has grown to
2500 vpd, the sandy subgrade has 22%
passing the No. 200 sieve and the hot
mix has lost 65% of its strength, what
minimum thickness of hot mix overlay
will restore the pavement to its
required strength?
For a highway with an
AADT of 2500 vpd, try
Table 6.03a
• for AADT of 2500
use third row
• for silty sand with
22% passing no. 200
use second column
• The required design
is:
HM: 90 mm
B: 150 mm
SB: 300 mm
GBE: 530 mm
TABLE 6.03 a
STRUCTURAL DESIGN GUIDELINES FOR FLEXIBLE PAVEMENTS
- KING'S HIGHWAYS AND FREEWAYS
(After: "Pavement Design and Rehabilitation Manual", 1990)
Subgrade Material
Gravels
Range of
Pavement
and Sands
SANDS AND SILTS
Lacustrine
Varved &
AADT
Structure
Suitable as
Percent Passing No. 200 Sieve
Clays
Leda Clays
Elements
Gran. Borrow
<40%
40 - 55%
>55%
HM
130
130
130
130
130
130
B
150 - 250
150
150
150
150
150
SB
---
300 - 450
450 - 600
600 - 800
450
450 - 1100
GBE
410 - 510
610 - 710
710 - 810
810 - 945
710
710 - 1145
HM
120 - 130
120 - 130
120 - 130
120 - 130
120 - 130
120 - 130
3000 -
B
150 - 250
150
150
150
150
150
4000
SB
---
300 - 450
450 - 600
600 - 800
450
450 - 1100
GBE
390 - 510
590 - 710
690 - 810
790 - 945
690 - 710
690 - 1145
HM
90
90
90
90
90
90
2000 -
B
150
150
150
150
150
150
3000
SB**
---
300
450
600
450
800
GBE
330
530
630
730
630
865
> 4000
HM
50
50
50
50
50
50
1000 -
B
150
150
150
150
150
150
2000
SB**
---
250
300
450
300
450 (300 - 600)
GBE
250
415
450
550
450
550 (450 - 650)
HM
50
50
50
50
50
50
200 -
B
150
150
150
150
150
150
1000
SB**
---
150
250
300
250
300 (250 - 450)
GBE
250
350
415
450
415
450 (415 - 550)
Notes: All AADT Volumes refer to Present Traffic
HM: Hot Mix Asphalt & Thickness (mm)
B: Base Thickness (mm)
SB: Subbase Thickness (mm)
GBE: Equivalent Thickness of Granular Base (mm)
( 1 mm HM = 2 mm B = 3 mm SB )
**: Proposed subbase thicknesses may be decreased or increased respectively
for harder or softer subgrade conditions in each category, except for
varved & leda clay subgrades where exceptionally large ranges are shown
TABLE 6.02
GRANULAR BASE EQUIVALENCY FACTORS
The
recommended
design:
Layer
Layer
Thickness
(mm)
Equivalency
(After: "Pavement Design and Rehabilitation Manual", 1990)
NEW PROJECTS
Material
Equivalency
Factor
Factor
Hot Mix
New or Recycled HL
Granular A in Base
Granular B in Subbase
Base
Cement Treated Material in Subbase (with Gr. A base)
Cement Treated Material in Base (no subbase)
Subbase
Bituminous Treated Material in Base (with Gr. A subbase)
Cold Mix
2.00
1.00
0.67
1.40
1.80
1.50
1.80
1.00
(mm)
90
2.00
180
150
1.00
150
300
0.67
201
Total Granular Base Equivalency (mm):
OGDL (Open Graded Drainage Layer)
Granular Base
Equivalency
531
RESURFACING PROJECTS
The existing
design:
Equivalency
Material
Layer
Crushed RBM* (in base)
Bituminous Treated Crushed RBM*
Crushed RBM* Blended with New Granular A
65% of HM
strength lost
Pulverized Bituminous Surface Mixed with Existing Base
EF of HM =
2-(2-1)*0.65
=1.35
Old Mix
HL
Hot
Old Granular Base
Base
Old Granular Subbase
Factor
1.00
1.50
1.00
1.00
1.25
0.75
0.50
RECONSTRUCTION PROJECTS
SubbaseEquivalency
Material
Factor
Granular A Layer
Old HL
Old Granular Base
Old Granular Subbase
1.00
1.00
0.60
0.40
Granular Base
Equivalency
Layer
Thickness
(mm)
Equivalency
Factor
75
1.35
101.25
180
0.75
135
300
0.50
150
Existing GBE (mm):
(mm)
386.25
Example 2
Extra Strength Required =
531 – 386.25 =144.75 mm of new Granular A
Since overlay will be with new Hot Mix, only half
of this thickness of new hot mix will be needed.
Overlay Thickness Required =
144.75/2 = 72.375 ≈ 80
mm
of new Hot Mix