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Geotechnical Aspects of Pavements Reference Manual

Text Versions Of Graphs and Images

Alternative Text for Figure 3-6

Figure 3-6. Approximate pavement cost for varying subgrade support conditions (B.Vandre, personal communication).
Cost per 1000 Square Yards of Surface Area (Rounded to Closest $0.05K)
 Million ESALs0.100.501.005.00101520
AsphaltCBR=14.405.856.658.809.8510.6511.00
Base / Granular BorrowCBR=25.806.857.358.559.159.609.80
CBR=34.405.155.506.456.957.457.60
CBR=43.654.204.555.355.756.206.35
CBR=53.103.553.804.404.755.105.25
CBR=62.753.103.303.804.054.304.45
CBR=72.002.552.753.353.603.904.00
CBR=81.802.152.252.702.953.203.40
CBR=91.802.002.052.352.502.702.80

[ Return To Figure 3-6 ]

Alternative Text for Figure 4-19

Figure 4-19. Particle size limit by different classifications systems.
Comparison of Particle Size Limit by the AASHTO and Unified Soil Classification Systems
Grain Size (mm) Sieve Unified AASHTO
0.010 Silt and ClaySilt and Clay
0.075No. 200
0.100 SandfineSandfine
0.425No. 40
1.000 mediumcoarse
2.000No. 10
4.750No. 4coarse 
10.000 GravelfineGravel
19.0003/4"
76.0003"coarse

[ Return To Figure 4-19 ]

Alternative Text for Figure 5-17

Figure 5-17. Correlations between subgrade resilient modulus and other soil properties (1 psi = 6.9 kPa; from Huang, 1993, after Van Til et al., 1972).
S, Soil Support ValueModulus, MR (psi)R Value (CA)Modulus, MR (psi)R Value (WA)Modulus, MR (psi)CBR (KY)Modulus, MR (psi)TX triaxial classModulus, MR (psi)Group IndexModulus, MR (psi)

(X.X) = Estimated Value

NOTE: Soil properties values are approximate and estimated based on the log scale of Subgrade Resilient Modulus, MR, from the original figure included in the FHWA 05-037, May 2006, NHI Course No. 132040, Geotechnical Aspects of Pavements Reference Manual/Participant Workbook

10.040,0009047,0009047,50010044,0002.040,000010,000
9.534,0008540,0008541,0009542,500(2.5)30,000(2.5)8,800
9.027,0008034,0008035,8009041,0003.023,00057,200
8.522,0007528,0007529,1008540,000(3.5)16,000(7.5)6,000
8.019,0007027,5007025,0008039,0004.011,300105,000
7.516,0006520,0006521,2007537,000(4.5)7,400(12.5)4,300
7.013,5006017,0006018,0007036,0005.04,800153,700
6.511,3005514,4005515,5006533,800(5.5)3,200(17.5)3,200
6.09,4005012,2005013,4006031,2006.02,080202,500
5.57,9004510,1004511,5005529,200 
5.06,400408,800409,6005027,900
4.55,200357,400358,2004525,400
4.04,400306,000306,8004023,900
3.53,700255,000254,7503521,500
3.03,000204,600204,9003019,800
2.52,700153,600154,2002517,000
2.02,080103,100103,6002015,000
1.51,70052,55053,0001512,000
1.01,46002,15002,580109,600
 9.59,200
99,000
8.58,600
88,200
7.57,800
77,450
6.57,000
66,600
5.56,200
55,800
4.55,200
44,900
3.54,500
34,100
2.53,500
23,050
1.52,400
11,890

[ Return To Figure 5-17 ]

Alternative Text for Figure 5-19

Figure 5-19. Correlations between structural layer coefficient a2 and various strength and stiffness parameters for unbound granular bases (AASHTO, 1993).
CBR (Scale derived by averaging correlations obtained from Illinois)Structural Coefficient, a sub 2R-value (Scale derived by averaging correlations obtained from California, New Mexico and Wyoming)Structural Coefficient, a sub 2Texas Triaxial (Scale derived by averaging correlations obtained from Texas)Structural Coefficient, a sub 2Modulus - 1000 psi (Scale derived on NCHRP project)Structural Coefficient, a sub 2
NOTE: Soil properties values are approximate and estimated based on the scale for Structural Coefficient, a2, from the original figure included in the FHWA 05-037, May 2006, NHI Course No. 132040, Geotechnical Aspects of Pavements Reference Manual/Participant Workbook
1000.140850.1402.00.140300.140
700.130800.1302.50.105250.120
600.125700.1053.50.080200.095
500.115600.0854.00.055150.070
400.105500.060 
300.095 
200.070

[ Return To Figure 5-19 ]

Alternative Text for Figure 5-20

Figure 5-20. Correlations between structural layer coefficient a2 and various strength and stiffness parameters for cement-treated granular bases (AASHTO, 1993).
Unconfined Compressive Strength (psi) 7 day break (Scale derived by averaging correlations from Illinois, Louisiana and Texas)Structural Coefficient, a sub 2Modulus - 1000 psi (Scale derived on NCHRP project)Structural Coefficient, a sub 2
NOTE: Soil properties values are approximate and estimated based on the scale for Structural Coefficient, a2, from the original figure included in the FHWA 05-037, May 2006, NHI Course No. 132040, Geotechnical Aspects of Pavements Reference Manual/Participant Workbook
10000.250100.265
8000.22090.240
6000.19080.215
4000.15570.190
2000.12560.150
 50.115

[ Return To Figure 5-20 ]

Alternative Text for Figure 5-21

Figure 5-21. Correlations between structural layer coefficient a2 and various strength and stiffness parameters for bituminous-treated granular bases (AASHTO, 1993).
Marshall Stability, lb. (Scale derived by correlation obtained from Illinois) Structural Coefficient, a sub 2 Modulus - 1000 psi (Scale derived on NCHRP project) Structural Coefficient, a sub 2
NOTE: Soil properties values are approximate and estimated based on the scale for Structural Coefficient, a2, from the original figure included in the FHWA 05-037, May 2006, NHI Course No. 132040, Geotechnical Aspects of Pavements Reference Manual/Participant Workbook
19000.3304 
18000.3203
17000.3052.5
16000.2952
15000.2851.5
14000.2701
13000.2604.00.335
12000.2503.00.275
11000.2402.50.250
10000.2302.00.220
9000.2151.50.190
8000.2051.00.125
7000.190 
6000.180
5000.170
4000.160
3000.145
2000.125
1000.090
00.065

[ Return To 5-21 ]

Alternative Text for Figure 5-22

Figure 5-22. Correlations between structural layer coefficient a3 and various strength and stiffness parameters for unbound granular subbases (AASHTO, 1993).
CBR (Scale derived by averaging correlations obtained from Illinois) Structural Coefficient, a sub 3 R-value (Scale derived by averaging correlations obtained from California, New Mexico and Wyoming) Structural Coefficient, a sub 3 Texas Triaxial (Scale derived by averaging correlations obtained from Texas) Structural Coefficient, a sub 3 Modulus - 1000 psi (Scale derived on NCHRP project) Structural Coefficient, a sub 3
NOTE: Soil properties values are approximate and estimated based on the scale for Structural Coefficient, a2, from the original figure included in the FHWA 05-037, May 2006, NHI Course No. 132040, Geotechnical Aspects of Pavements Reference Manual/Participant Workbook
1000.140900.1402.00.140200.135
700.130800.1303.00.120150.110
500.125700.1204.00.085140.105
400.120600.1055.00.045130.095
300.110500.090 120.090
200.095400.070110.085
100.080300.055100.075
50.050250.050 

[ Return To Figure 5-22 ]

Alternative Text for Figure 5-27

Figure 5-27. Correction of effective modulus of subgrade reaction for potential loss of subbase support (AASHTO, 1993).
LS = 0
Little or No Erosion
LS = 1.0LS = 2.0LS = 3.0
Most Erosion
Effective Modulus of Subgrade Reaction, k (pci)Effective Modulus of Subgrade Reaction, k (pci) - Corrected for Potential Loss of SupportEffective Modulus of Subgrade Reaction, k (pci)Effective Modulus of Subgrade Reaction, k (pci) - Corrected for Potential Loss of SupportEffective Modulus of Subgrade Reaction, k (pci)Effective Modulus of Subgrade Reaction, k (pci) - Corrected for Potential Loss of SupportEffective Modulus of Subgrade Reaction, k (pci)Effective Modulus of Subgrade Reaction, k (pci) - Corrected for Potential Loss of Support
NOTE: Corrected keff values are approximate and estimated based on the original figure included in the FHWA 05-037, May 2006, NHI Course No. 132040, Geotechnical Aspects of Pavements Reference Manual/Participant Workbook
11.01.301.01.451.02---
22.021.521.42.201.0
33.032.231.731.2
44.042.842.041.5
55.053.352.351.7
66.063.962.761.8
77.074.472.971.9
88.084.883.282.0
99.095.393.492.2
1010.0105.9103.6102.4
2020.02010.5205.7203.4
3031.53015.5307.2304.1
4041.54019.0408.8404.8
5052.05022.55010.0505.3
6062.06026.06011.5606.0
7072.07029.57013.5706.5
8083.08033.08014.5806.9
9094.09036.09015.7907.3
100105.510040.010016.71007.7
200208.520069.020025.020011.5
300314.0300100.030032.030014.5
400417.0400134.040038.540017.5
500529.0500161.050044.550019.0
600639.0600181.060049.060021.0
700743.0700200.070055.070022.5
800862.0800229.080060.080024.0
900980.0900254.090064.590025.5
1000Not Shown1000269.0100067.0100027.0
20002000485.02000109.0200039.0

[ Return To Figure 5-27 ]

Alternative Text for Figure 5-28

Figure 5-28. Effective dynamic k value determination from d0 and AREA (AASHTO, 1993).
k = 50 pcik = 100 pcik = 150 pcik = 200 pcik = 250 pcik = 300 pcik = 500 pcik = 1000 pci
Deflection Basin AREA, inchesMaximum deflection, d sub 0, milsDeflection Basin AREA, inchesMaximum deflection, d sub 0, milsDeflection Basin AREA, inchesMaximum deflection, d sub 0, milsDeflection Basin AREA, inchesMaximum deflection, d sub 0, milsDeflection Basin AREA, inchesMaximum deflection, d sub 0, milsDeflection Basin AREA, inchesMaximum deflection, d sub 0, milsDeflection Basin AREA, inchesMaximum deflection, d sub 0, milsDeflection Basin AREA, inchesMaximum deflection, d sub 0, mils
NOTE: Corrected keff values are approximate and estimated based on the original figure included in the FHWA 05-037, May 2006, NHI Course No. 132040, Geotechnical Aspects of Pavements Reference Manual/Participant Workbook
25 2525.52517.12512.62510.2258.5255.1252.5
262621.82614.72611.0268.8267.4264.4262.2
272718.62712.4279.3277.5276.2273.8271.8
282815.52810.3287.7286.2285.3283.2281.5
2924.62912.6298.4296.3295.1294.2292.6291.3
3019.8309.9306.6305.0304.0303.4302.0301.0
3115.3317.6315.2313.8313.1312.5311.6310.8
3211.2325.5323.6322.8322.3321.8321.2320.6
337.7333.8332.6331.9331.6331.4330.8330.5
344.7342.4341.7341.2341.0340.8340.4340.3
352.2351.0350.8350.4350.4350.4350.2350.1
360.0360.0360.0360.0360.0360.0360.0360.0

[ Return To Figure 5-28 ]

Alternative Text for Figure 5-31

Figure 5-31. Correlation between coefficient of lateral earth pressure and overconsolidation ratio for clays of various plasticity indices (Carter and Bentley, 1991).
Plasticity Index = 10Plasticity Index = 20Plasticity Index = 30Plasticity Index = 60Boston Blue Clay, PI=23 (Ladd, 1965)
Deflection Basin AREA, inchesMaximum deflection, d sub 0, milsDeflection Basin AREA, inchesMaximum deflection, d sub 0, milsDeflection Basin AREA, inchesMaximum deflection, d sub 0, milsDeflection Basin AREA, inchesMaximum deflection, d sub 0, milsDeflection Basin AREA, inchesMaximum deflection, d sub 0, mils
NOTE: Corrected keff values are approximate and estimated based on the original figure included in the FHWA 05-037, May 2006, NHI Course No. 132040, Geotechnical Aspects of Pavements Reference Manual/Participant Workbook
10.7010.6010.5110.4410.50
20.8820.7920.7020.611.30.63
31.0330.9030.8130.7320.73
41.1241.0140.9440.8330.87
51.2051.1151.0250.9540.96
61.2761.2061.1261.0561.15
71.3571.2971.2271.1581.27
81.3981.3881.3281.24101.39
91.4491.4791.4191.33151.69
101.48101.54101.48101.41 
201.81202.12202.26202.10
302.01302.48302.71302.60

[ Return To 5-31 ]

Alternative Text for Figure 5-33

Figure 5-33. Nomograph for estimating swell rate constant (AASHTO, 1993).
Moisture Supply = Low on Left AxisMoisture Supply = Midpoint of Left AxisMoisture Supply = High on Left Axis
Road Bed Soil Fabric on Right AxisSwell Rate ConstantRoad Bed Soil Fabric on Right AxisSwell Rate ConstantRoad Bed Soil Fabric on Right AxisSwell Rate Constant
NOTE: The input for this graph is very subjective and will give only a very approximate estimate - Swell rate varies from 0.04 to 0.20. Right Axis is divided into 5 equal divisions for these tables where "Tight" = 0 and "Fractured" = 5.
00.04000.04000.105
10.06710.08510.180
20.08520.11020.190
30.10030.12830.195
40.11140.13940.197
50.12050.14850.200

[ Return To Figure 5-33 ]

Alternative Text for Figure 7-9

Figure 7-9. Time Factor for 50% Drainage (ERES, 1999).
Slope Factor, (S1) Plotted on Log ScaleTime Factor, (T 50) Plotted on Log Scale
00.700
10.217
20.140
30.118
40.095
50.830
60.074
70.069

[ Return To Figure 7-9 ]

Alternative Text for Figure 7-17

Figure 7-17. Guide to collapsible soil behavior (Rollings and Rollings, 1996).
Gs = 2.60 Saturation = 100% CurveGs = 2.70 Saturation = 100% Curve
Liquid Limit
%
Natural Dry Density
lb/ft3
Liquid Limit
%
Natural Dry Density
lb/ft3

For Any Value of Liquid Limit: Collapse is Likely for Natural Dry Densities Equal To or Less Than the Saturation = 100% Curve Natural Dry Density Value.

For Any Value of Liquid Limit: Swelling is Likely for Natural Dry Densities Greater Than the Saturation = 100% Curve Natural Dry Density Value

For Any Value of Liquid Limit: Collapse is Likely for Natural Dry Densities Equal To or Less Than the Saturation = 100% Curve Natural Dry Density Value.

For Any Value of Liquid Limit: Swelling is Likely for Natural Dry Densities Greater Than the Saturation = 100% Curve Natural Dry Density Value

13.5120.015120.0
20106.520109.0
3091.03093.0
4079.54081.0
5070.05071.5
6063.06064.0
7057.07058.0
8052.08053.0
8550.08750.0

[ Return To Figure 7-17 ]

Alternative Text for Figure 7-21

Figure 7-21a. Thickness design curves with geosynthetics for a) single wheel loads (after USFS, 1977, and FHWA NHI-95-038, 1998).
cNcRequired Aggregate Thickness
inches (mm)
5,000 lb10,000 lb15,000 lb20,000 lb25,000 lb30,000 lb35,000 lb
psi(kPa)Full Size pickup truck2 yd3 Wheel Loader3 yd3 Wheel Loader4 yd3 Wheel Loader5 yd3 Scraper15 yd3 Scraper20 yd3 Scraper
1( 7 )47.3( 1201 )66.5( 1689 ) 
1.5( 10 )39.0( 991 )54.2( 1377 )67.7( 1720 ) 
2( 14 )33.9( 861 )47.2( 1199 )58.5( 1486 )68.7( 1745 ) 
2.3( 16 ) 70.0( 1778 ) 
3( 21 )27.8( 706 )38.5( 978 )47.5( 1207 )55.5( 1410 )61.0( 1549 )69.2( 1758 ) 
3.5( 24 ) 70.0( 1778 )
4( 28 )24.3( 617 )33.0( 838 )40.5( 1029 )47.3( 1201 )52.0( 1321 )56.1( 1425 )62.7( 1593 )
5( 34 )21.3( 541 )29.5( 749 )36.2( 919 )42.2( 1072 )45.9( 1166 )51.0( 1295 )55.9( 1420 )
6( 41 )18.9( 480 )27.0( 686 )32.8( 833 )38.0( 965 )41.7( 1059 )46.1( 1171 )50.6( 1285 )
7( 48 )17.4( 442 )24.9( 632 )30.5( 775 )35.0( 889 )38.7( 983 )42.7( 1085 )47.0( 1194 )
8( 55 )16.6( 422 )23.0( 584 )28.2( 716 )32.4( 823 )36.2( 919 )40.0( 1016 )44.0( 1118 )
9( 62 )15.0( 381 )21.5( 546 )26.6( 676 )30.7( 780 )34.0( 864 )37.9( 963 )41.4( 1052 )
10( 69 )13.9( 353 )20.5( 521 )25.2( 640 )29.0( 737 )32.2( 818 )36.0( 914 )39.4( 1001 )
20( 138 )9.4( 239 )13.7( 348 )18.2( 462 )19.5( 495 )21.5( 546 )24.2( 615 )27.1( 688 )
30( 207 )7.1( 180 )10.7( 272 )12.5( 318 )14.5( 368 )16.3( 414 )28.5( 724 )20.4( 518 )
37( 255 )6.0( 152 ) 
40( 276 )6.0( 152 )8.2( 208 )9.9( 251 )11.1( 282 )12.8( 325 )14.6( 371 )16.1( 409 )
50( 345 )6.0( 152 )6.1( 154 )7.8( 198 )8.6( 218 )9.8( 249 )10.8( 274 )11.9( 302 )
51.5( 355 )6.0( 152 )6.0( 152 ) 
55.5( 383 )6.0( 152 )6.0( 152 )6.0( 152 ) 
60( 414 )6.0( 152 )6.0( 152 )6.0( 152 )6.3( 160 )7.0( 178 )7.3( 185 )8.1( 206 )
61.7( 425 )6.0( 152 )6.0( 152 )6.0( 152 )6.0( 152 )6.0( 152 ) 
62.5( 431 )6.0( 152 )6.0( 152 )6.0( 152 )6.0( 152 )6.0( 152 )6.0( 152 )6.0( 152 )
63( 434 )6.0( 152 )6.0( 152 )6.0( 152 )6.0( 152 )6.0( 152 )6.0( 152 )6.0( 152 )
70( 483 )6.0( 152 )6.0( 152 )6.0( 152 )6.0( 152 )6.0( 152 )6.0( 152 )6.0( 152 )
80( 552 )6.0( 152 )6.0( 152 )6.0( 152 )6.0( 152 )6.0( 152 )6.0( 152 )6.0( 152 )
Figure 7-21b. Thickness design curves with geosynthetics for b) dual wheel loads (after USFS, 1977, and FHWA NHI-95-038, 1998).
cNcRequired Aggregate Thickness
inches (mm)
Tandem 8,000 lbTandem 11,000 lbDual Wheel, Single Axle 9,000 lbTandem 17,5000 lb
psi(kPa)10 yd3 Dump Truck14-16 yd3 Dump TruckHighway LegalLegal Log Truck
1( 7 )52.7( 1339 )59.3( 1506 )65.8( 1671 ) 
1.2( 8 ) 70.0( 1778 )
1.5( 10 )40.7( 1034 )46.8( 1189 )52.3( 1328 )60.5( 1537 )
2( 14 )34.0( 864 )39.7( 1008 )44.9( 1140 )52.0( 1321 )
3( 21 )26.9( 683 )31.8( 808 )36.3( 922 )42.0( 1067 )
4( 28 )22.5( 572 )26.9( 683 )31.4( 798 )35.4( 899 )
5( 34 )20.3( 516 )23.8( 605 )28.0( 711 )31.4( 798 )
6( 41 )18.2( 462 )21.5( 546 )25.6( 650 )28.4( 721 )
7( 48 )16.6( 422 )29.4( 747 )23.4( 594 )25.5( 648 )
8( 55 )15.5( 394 )17.8( 452 )21.7( 551 )23.5( 597 )
9( 62 )14.4( 366 )16.5( 419 )20.3( 516 )21.9( 556 )
10( 69 )13.4( 340 )15.5( 394 )18.9( 480 )20.5( 521 )
20( 138 )7.6( 193 )8.6( 218 )11.5( 292 )11.8( 300 )
25( 172 )6.0( 152 ) 
29.8( 205 )6.0( 152 )6.0( 152 ) 
30( 207 )6.0( 152 )6.0( 152 )7.6( 193 )8.0( 203 )
36( 248 )6.0( 152 )6.0( 152 )6.0( 152 )6.0( 152 )
40( 276 )6.0( 152 )6.0( 152 )6.0( 152 )6.0( 152 )
50( 345 )6.0( 152 )6.0( 152 )6.0( 152 )6.0( 152 )
60( 414 )6.0( 152 )6.0( 152 )6.0( 152 )6.0( 152 )
63( 434 )6.0( 152 )6.0( 152 )6.0( 152 )6.0( 152 )
70( 483 )6.0( 152 )6.0( 152 )6.0( 152 )6.0( 152 )
80( 552 )6.0( 152 )6.0( 152 )6.0( 152 )6.0( 152 )

[ Return To Figure 7-21 ]

Alternative Text for Figure C-1

Figure C-1. Chart for estimating structural layer coefficient of dense-graded asphalt concrete based on the elastic (resilient) modulus (AASHTO, 1993).
Elastic Modulus
EAC, (psi) of Asphalt Concrete (at 68°F)Structural Layer Coefficient, a1, for Asphalt Concrete Surface Course
105,0000.200
150,0000.255
200,0000.295
250,0000.330
300,0000.365
350,0000.390
400,0000.420
450,0000.445
500,0000.460

[ Return To Figure C-1 ]

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Updated: 04/07/2011
 

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