Pavement Performance
Present Serviceability Rating
“The judgment of an observer as to the current ability of a pavement to serve the traffic it is meant to serve”
10
Present Serviceability Index
PC01.0RD38.1SV1log9.103.5PSI 2
PC09.0SV1log8.141.5PSI
Flexible Pavements
Rigid Pavements
24
Pavement Performance
Very good
Good
Fair
Poor
Very poor
5
4
3
2
1
0
PSI
ESALS (log scale)
Limit for Low-Volume Roads
Limit for High-Volume Roads
25
Pavement Performance
5
4
3
2
1
0
PSI
ESALS (log scale)
Acceptability Limit
75% Time
40%Drop
40%Drop
12% Time
Each $1 spent onmaintenance here
Ends up costing $4if delayed to here
26
Pavement Performance
Wt
terminal serviceability
tt 4.2 4.2 1.5 Wp
pt
InitialConstruction
failure
4.2
1.5
30
Flexible Performance
9.365.93 4.33
9.364.7918
10 1 1 0.64 118 1
SN SN
3.23
5.19 518 .193.23
0.081 18 1 10940.4 0.41 1 1
SN SN
31
Pavement Performance
Wt
terminal serviceabilitypt
InitialConstruction
failure
4.2
1.5
5.1910940.4
SN 118
9.t 36Wp 4
0..2
64.2 1.5
4 SN 1
32
Pavement Performance
Wt
terminal serviceabilitypt
InitialConstruction
failure
4.2
1.5
5.19
10940.4SN 1
t 189.36
4.2 p W4.2 1.5 0.64 SN 1
33
Pavement Performance
Wt
terminal serviceabilitypt
InitialConstruction
failure
4.2
1.5
t 18
10 105.19 9.364.2 p 1094 Wlog 0.4 log4.2 1.5 SN 1 0.64 SN 1
34
Pavement Performance
Wt
terminal serviceabilitypt
InitialConstruction
failure
4.2
1.5
t10
1810 9.36
5.19
4.2 plogW 4.2 1.5log 10940.64 SN 1 0.4
SN 1
35
Pavement Performance
Wt
terminal serviceabilitypt
InitialConstruction
failure
4.2
1.5
t10
9.3610 18 10
5.19
4.2 plog4.2 1.5log W log 0.64 SN 1 10940.4SN 1
36
Pavement Performance
Wt
terminal serviceabilitypt
InitialConstruction
failure
4.2
1.5
t10
10 18 10
5.19
4.2 plog4.2 1.5log W 9.36log SN 1 0.20 10940.4SN 1
37
AASHO Road Test
Average Mean Temperature (July) 24.5°C (76oF)
Average Mean Temperature (January) -2.8°C (27oF)
Annual Average Rainfall 837 mm (34 in)
Average Depth of Frost (for fine-grained soil) 711 mm (28 in)
Climate
39
AASHO Road Test
Soil Classification A-6
Percent Passing a #200 Sieve 82%
Liquid Limit 31%
Plasticity Index 16%
Average Degree of Saturation 85%
Average CBR 2.9
Subgrade
40
Flexible Performance
1972
t
10
10 18 10
5
i
.19
4.2 plog4.2 1.5log W 9.36log SN 1 0.20 10940.
1log 0.372 S 3.
S 1
0R4
N
41
SubgradeSupportFactor
RegionalClimateFactor
Regional Factor
42
Condition R value
Roadbed materials frozen to a depth of 5 in. or more (winter)
Roadbed materials dry (summer and fall)
Roadbed materials wet (spring thaw)
0.2 – 1.0
0.5 – 1.5
4.0 – 5.0
Flexible Performance
1986
10
t10
10 18 10
5.19
R
4.2 plog4.2 1.5log W 9.36log SN 1 0.20 10940.4S
2.32log M 8.07
N 1
45
SeasonallyAdjustedResilientModulus
Predicted Pavement Life
t
10
10 10 10 R
5.19
T
4.2 plog4.2 1.5log 9.36log 1 0.20 2.32log M 8.071S 0940.4
1
N
SN
w
48
Design Equation w/ FS
10 10 10log log logTt RW w F
PredictedTrafficLevels
PredictedPavement
Life
Factorof
Safety
51
Design Equation
R 0
10
10 18 10 10 R
5.19
4.2 plog4.2 1.5log W 9.36log SN 1 0.20 2.32log M 8.0710940.SN 1
Z S4
1993
59
Reliability
Recommended Reliability
Functional Classification Urban Rural
Interstate and Other Freeways 85 – 99.9% 80 – 99.9%
Principal Arterials 80 – 99% 75 – 99%
Collectors 80 – 95% 75 – 95%
Local 50 – 80% 50 – 80%
60
ReliabilityReliability
(%) ZRReliability
(%) ZR
50 -0.000 93 -1.476
60 -0.253 94 -1.555
70 -0.524 95 -1.645
75 -0.674 96 -1.751
80 -0.841 97 -1.881
85 -1.037 98 -2.054
90 -1.282 99 -2.327
91 -1.340 99.9 -3.090
92 -1.405 99.99 -3.75061