Pavement Structural Analysis of the Design Recommendations for ...

7 

Pavement Structural Analysis of the 

Design Recommendations for Reconstructing 

I-96 (M-39 to Schaeffer Road) 

Report No. MIDOT-15953-2/1 

Prepared for: 

Mr. Curtis Bleech 

Michigan Department of Tranpsortation 

Construction and Technology Division/Laboratory 

P.O. Box 30049 

Lansing, Michigan 48909 

Prepared by: 

Harold L. Von Quintus, P.E. 

ERES Consultants – A Division of Applied Research Associates 

26 Stillmeadow 

Round Rock, Texas 78664 

August 2004 

i

Pavement Structural Analysis August 2004 

Report No. 15953-2/1 ARA-ERES Consultants 




Report No. MIDOT-15953-2/1 

Prepared for: 

Mr. Curtis Bleech 

Michigan Department of Tranpsortation 

Construction and Technology Division/Laboratory 

P.O. Box 30049 

Lansing, Michigan 48909 

Prepared by: 

Harold L. Von Quintus, P.E. 

ERES Consultants – A Division of Applied Research Associates 

26 Stillmeadow 

Round Rock, Texas 78664 

Harold L. Von Quintus, P.E. August 2004 

Texas Registration 46169 

ii



Executive Summary 

I-96 between M-39 and Schaeffer Road, just west of Detroit, Michigan, is planned for 

reconstruction in 2005. The Michigan Department of Transportation (DOT) completed a 

design for the reconstruction of this segment of I-96 in accordance with the 1993 

AASHTO DARWin program. (1) The objective of this study was to analyze the proposed 

flexible pavement layer thickness and material types recommended for this segment 

along I-96. Two mechanistic-empirical (M-E) design/analysis methods were used to 

analyze the pavement design. One of the M-E design/analysis methods was the same one 

used to prepare A Simplified Catalog of Solutions, and the second one is the new M-E 

Pavement Design Guide developed under NCHRP 1-37A. (2,3) 

Results from these analyses suggest that the proposed pavement structure will be 

adequate relative to cracking. In fact, the tensile strain calculated under the standard 

design load is less than the value that has been typically assumed for the endurance limit. 

The one concern is with rutting and distortion. Both M-E analysis methods predict levels 

of rutting that exceed the allowable level of 0.50 inches within the analysis period. Using 

a PG 76-22 asphalt in the top two layers (the wearing surface and leveling course) will 

reduce the rutting to an acceptable level. Whether a PG 70-22P or PG 76-22 is used 

should be defined based on asphalt or mixture modulus testing or some type of torture 

test to ensure that the HMA mixtures will be resistant to rutting. 

Prior to construction, it should be confirmed that the pavement materials meet or exceed 

the assumptions used in design, regardless of the design method. It is also recommended 

that sufficient testing be completed during construction to ensure that the design 

assumptions are satisfied. 

iii



Table of Contents 

Section Page 

1. Introduction .................................................................................................................... 1 

2. Study/Design Objective ..................................................................................................... 1 

3. Project Design Parameters ................................................................................................. 1 

3.1 Design Traffic ........................................................................................................ 1 

3.2 Subsurface Investigations – Soil Support Design Value ....................................... 5 

3.3 Non-Frost Susceptible Material ............................................................................. 7 

3.4 Hot Mix Asphalt Mixtures................................................................................... 11 

3.5 Subsurface Drainage System ............................................................................... 13 

4. Mechanistic-Empirical Thickness Design-Evaluation Method ....................................... 13 

4.1 Pavement Structural Design Assumptions........................................................... 14 

4.2 Evaluation Criteria............................................................................................... 15 

4.3 Simplistic M-E Analysis Method......................................................................... 15 

4.4 New M-E Pavement Design Guide Software ...................................................... 19 

5. Summary of Evaluations.................................................................................................. 21 

6. Limitations .................................................................................................................. 22 

7. References .................................................................................................................. 23 

Appendices: 

A Summary of Truck Traffic Equivalent Single Axle Load Applications Computed 

for the Base Year 2005 .................................................................................................... 25 

B Summary of Repeated Load Resilient Modulus Tests Extracted from the LTPP 

Database for the Michigan Sites ...................................................................................... 32 

C Layer Properties and Pavement Responses Computed for the I-96 Design Cross 

Section .................................................................................................................. 36 

C.1 HMA Modulus Determination............................................................................. 36 

C.2 Unbound Layer Modulus Determination............................................................. 38 

C.3 EVERSTRS Output for Fatigue Cracking Analysis ............................................ 40 

C.4 EVERSTRS Output for HMA Rutting Analysis ................................................. 42 

D Analysis of the Proposed Design Cross Section of I-96 Using the New M-E 

Pavement Design Guide Software ................................................................................... 43 

iv



1. Introduction 

I-96 between M-39 and Schaeffer Road, just west of Detroit, Michigan, is planned for 

reconstruction in 2005. The Michigan Department of Transportation (DOT) completed a 

design for the reconstruction of this segment of I-96 in accordance with the 1993 

AASHTO DARWin program. (1) Figure 1 shows the pavement design (material types and 

layer thickness) resulting from that design procedure. 

Mr. Curtis Bleech with the Michigan DOT requested that an analysis of that pavement 

structural design be completed using a mechanistic-empirical method for a 20 and 40year 

analysis period. The purpose of this document is to present the analyses completed 

for evaluating the design pavement cross sections (material types and layer thickness) 

recommended for the reconstruction of I-96 (refer to figure 1). 

2. Study/Design Objective 

The objective of this study was to analyze the flexible pavement layer thickness and 

material types recommended for the segment along I-96 between M-39 and Schaeffer 

Road using two mechanistic-empirical (M-E) design/analysis methods. One of the M-E 

design/analysis methods was the same one used to prepare A Simplified Catalog of 

Solutions, and the second one is the new M-E Pavement Design Guide developed under 

NCHRP 1-37A. (2,3) 

3. Project Design Parameters 

3.1 Design Traffic 




The traffic parameters that were used to determine the design number of 80-kN (18-kip) 

Equivalent Single Axle Loads (ESALs) in accordance with the 1993 AASHTO Design 

Guide are summarized below and were provided by the Michigan DOT. 

Average Annual Daily Commercial Traffic in 2005 = 9,600 

Initial Annual ESALs, both directions = 2,382,720 

Directional Distribution Factor = 0.56 

Lane Distribution Factor = 0.70 

Compound Commercial Traffic Growth Rate = 2.0% 

1



20-Year ESALs, one-way traffic = 22,694,400 

40-Year ESALS, one-way traffic = 56,400,000 

HMA TOP COURSE 

HMA LEVELING COURSE 

HMA BASE COURSE 

AGGREGATE BASE 

SAND SUBBSASE 

SILTY CLAY SOIL 

Figure 1 Pavement design resulting from the 1993 AASHTO Design Guide for 

the reconstruction of I-96. 

2 

HMA Top Course (PG 70-22P); 

1.5 inches; Air Voids = 7.5%; 

Vbe=10.5% 

HMA Leveling Course (PG 70- 

22P); 2.5 inches; Air Voids = 

7.5%; Vbe=10.5% 

HMA Base Course (PG 70-22); 

10 inches; Air Voids = 7.5%; 

Vbe= 9.5% 

OGDC Aggregate Base Course; 

16 inches (21AA-MOD) 

Crushed Stone Base 

Geotextile Separator-Fabric 

Sand Subbase, Class IIA; 8 inches 

Low Plasticity, Firm Silty Clay 

Soil



The truck traffic inputs for the new M-E Pavement Design Guide software, however, are 

the actual truck volume distribution and axle load distributions. Table 1 shows the truck 

traffic distribution that was used in this pavement design study. The Truck Traffic 

Classification (TTC) group for this urban freeway was assumed to be 3. (3) Figures 2–4 

show the axle load spectra for the single, tandem and tridem axles, respectively. 

Table 1 Truck Traffic Volume Distribution for the Base Year, 2005. 

Truck Type Normalized Volume Distribution, % 

4 0.90 

5 11.6 

6 3.6 

7 0.2 

8 6.7 

9 62.0 

10 4.8 

11 2.6 

12 1.4 

13 6.2 

Using the default normalized truck volume and axle weight distributions determined from 

an analysis of the Long Term Pavement Performance (LTPP) traffic data and the 

AASHTO equivalency factors, the number of 18-kip (80-kN) ESALs were estimated for 

the base year for this section of I-96. (3) Appendix A summarizes the computations for the 

ESALs using the normalized axle load distributions that are expected for this urban 

freeway. The number of ESALS was computed to be 4,411,425 in 2005 for both 

directions, which is almost twice the value used in the 1993 AASHTO design procedure 

(2,382,720 ESALs). The reason for this difference is not known, but indicates that the 

global default distribution values embedded in the new M-E Pavement Design Guide 

software may not be applicable to the truck traffic in Michigan, or at least should be 

confirmed prior to full-scale use. 

A lane distribution factor of 0.70 and a directional distribution of 0.56 were used to 

compute the design-lane ESALs for 2005 – a value of 1,729,279. As noted above, the 

ESALs determined from the volume and axle load normalized distributions 

recommended for use in the new M-E Pavement Design Guide are greater than those 

used in the design study completed by the Michigan DOT. The average number of 18kip 

(80-kN) ESALS per truck application determined using the normalized distributions 

was computed to be 1.259 (refer to Appendix A). 

3



Number of Monthly Single Axle 

Loads 

70000 

60000 

50000 

40000 

30000 

20000 

10000 

0 

0 10 20 30 40 50 

Single Axle Load, kips 

Figure 2 Monthly single axle load distribution or spectra for the base year for 

the segment of I-96 from M-39 to Schaeffer Road. 

Number of Monthly Tandem Axle 

Loads 

35000 

30000 

25000 

20000 

15000 

10000 

5000 

0 

0 20 40 60 80 100 

Tandem Axle Load, kips 

Figure 3 Monthly tandem axle load distribution or spectra for the base year for 


4



Number of Monthly Tridem Axle Loads 

3500 

3000 

2500 

2000 

1500 

1000 

500 

0 

0 20 40 60 80 100 120 

Tridem Axle Load, kips 

Figure 4 Monthly tridem axle load distribution or spectra for the base year for 


For the simplistic M-E analysis procedure, the design values recommended for use by the 

Michigan DOT were used in the design computations and checks because of the different 

types of trucks typically used in Michigan, as compared to other agencies from traffic 

data included in the LTPP database. Re-analyzing the Weighing-In-Motion (WIM) data 

for selected Michigan sites was beyond the scope of work for this thickness design study. 

3.2 Subsurface Investigations – Soil Support Design Value 

The logs of sixty-nine 5-fott (1.5-meter) borings were provided to determine the types of 

soils along this project. The soils along this portion of I-96 consist of varying thickness of 

fill or topsoil over a low plasticity, firm silty clay. 

The effective resilient modulus of the foundation soil is a design parameter required by 

the 1993 AASHTO Design Guide and M-E design procedures. The resilient modulus is 

determined from repeated load triaxial tests, and can have a significant impact on the 

flexible pavement layer thickness. Resilient modulus tests were unavailable for the soils 

along this roadway. The Michigan DOT used a design resilient modulus of 3,000 psi 

(20,684 kPa) in the AASHTO design. This design resilient modulus is based on 

5



Michigan’s experience and should be conservative for the existing foundation soil that 

will not be removed during the reconstruction of this segment along I-96. 

Repeated load resilient modulus tests of similar soils, however, are available in the LTPP 

database for various sites in Michigan. Figure 5 shows the average test results for this 

type of soil, which are similar to those estimated from correlations developed by Von 

Quintus, et al. (4) Thus, the repeated load resilient modulus test results shown in figure 5 

were used to estimate the design resilient modulus for the foundation soil for both M-E 

design procedures. 

Resilient Modulus, ksi 

10 

9 

8 

7 

6 

5 

4 

3 

2 

1 

0 

0 5 10 

Cyclic Deviator Stress, psi 

6 

Confinement = 2 psi 

Confinement = 4psi 


Figure 5 Average repeated load resilient modulus test results recovered from 

the LTPP database for silty clay soils, similar to those encountered 

along I-96. 

The correlations noted above only represent a best-guessed value for design. The design 

values used in the M-E design procedures are greater than the value suggested for use by 

the Michigan DOT (3,000 psi or 20,684 kPa) in the AASHTO DARWin program. The 

difference in these design resilient modulus values will be discussed in greater detail in a 

latter section of this report. 

To confirm the design resilient modulus values for the in place soils, however, it is 

suggested that repeated load resilient modulus tests be performed in the laboratory on 

undisturbed or re-compacted test specimens. If repeated load resilient modulus tests are 

not possible, deflection basins can be measured along the existing roadway and the elastic 

modulus back-calculated for the subgrade soils using the procedure used by Von Quintus 

et al, for LTPP. (5,6) If modulus values are back-calculated from deflection basins along I-



96, they should be adjusted using the correction factors recommended by Von Quintus, et 

al. (6) 

Based on the boring logs provided, the subgrade soils encountered along the section of I- 

96 are believed to have a frost susceptibility classification of moderate or medium using 

the Corps of Engineers classification system (refer to figure 6). (7) It is suggested that a 

non-frost susceptible material be placed above the subgrade to minimize the potential for 

frost heave over time. Thus, a minimum of 36 inches (914 mm) of non-frost susceptible 

materials were included in the pavement cross-sections analyzed in this study. 

Results from the subsurface investigations did not indicate ground water at the time of 

drilling. Seasonal variation in ground water is expected for this area. Thus, subsurface 

drains were assumed in the design computations for determining the required layer 

thickness. It is understood that subsurface drains and a geotextile fabric-separator are 

included in the planned reconstruction. 

3.3 Non-Frost Susceptible Material 

For this climatic area, the Michigan DOT requires that 36 inches (914 mm) of non-frost 

susceptible material be placed above any frost-susceptible soil based on historical data 

and experience. The thickness of non-frost susceptible material requirement was 

assumed for this design study and not re-evaluated, as noted above. 

Two unbound aggregate materials are available for use in the reconstruction of this 

segment along I-96: a class IIA sand subbase and a 21AA-MOD crushed stone aggregate 

base. Resilient modulus tests were completed and are available for similar materials from 

the FHWA-LTPP database for test sections in Michigan. This laboratory data was used to 

estimate the resilient modulus for each of these materials, similar to the method used to 

develop Pavement Structural Design Study – A Simplified Catalog of Solutions. (2) A 

geotextile fabric should be used as a separator layer between the crushed aggregate base 

and sand subbase. 

Sand Subbase Material 

It is understood that the existing sand material encountered in the borings along I-96 will 

be replaced with Class IIA material for the flexible pavement design option. Resilient 

modulus tests on the sand proposed for use were unavailable. However, repeated load 

resilient modulus tests performed on materials classified as sand subbases were 

previously extracted from the LTPP database. 

Figures 17 to 20 in Appendix B graphically present the distribution of the resilient 

modulus measured at specific stress states. It is important to note that the distributions 

appear to be normal for those groups with a sufficient number of tests. This normal 

distribution of resilient modulus values at specific stress states is also applicable to other 

unbound materials that have a sufficient number of resilient modulus tests. 

7



Table 2 summarizes the median resilient modulus values included in Appendix B for 

sandy soils and sand subbase materials. As tabulated, the median resilient modulus for 

the sand subbase material is about 18,500 psi (127,553 kPa) for all tests, as well as the 

tests for samples recovered from only the LTPP sites located in Michigan. 

Figure 6. Average rate of heave versus percentage finer than 0.02 mm for natural 

soil gradations. (6) 

8



Figure 7 shows the average test results for a Class IIA sand subbase material in Michigan 

that were extracted from the LTPP database. These average test results were used to 

determine the design resilient modulus for both M-E design procedures. 

Table 2 Median resilient modulus measured on the sand subbases and sand 

subgrades recovered from all of the LTPP sites and from those sites 

that are located in Michigan. 

Material/ 

Layer 

Stress State 

Median Resilient Modulus, psi (MPa) 

(Refer to figures 17 to 20 in Appendix B) 

All LTPP Sites LTPP Sites in Michigan 

Sand Confinement = 10 psi 18,400 (126.9) 18,700 (128.9) 

Subbase Cyclic Stress = 9 psi (N=62)* 

(N=10) 

Sand Confinement = 2.0 psi 7,700 (53.1) 

8,300 (57.2) 

Subgrade Cyclic Stress = 1.8 psi (N=440) 

(N=7) 

* N = number of resilient modulus tests within each group. 

Resilient Modulus, ksi 

35 

30 

25 

20 

15 

10 

5 

0 

0 50 100 150 

Bulk Stress, psi 

9 






Figure 7 Average repeated load resilient modulus test results extracted from 

the LTPP database for a sand subbase that is expected to be similar to 

the material placed along I-96.



Crushed Stone Aggregate Base Material 

The crushed stone aggregate base material planned for use along I-96 is a material that 

meets the Michigan DOT’s specification for a 21 AA-MOD material. Table 3 lists the 

gradation for this aggregate base material. The resilient modulus tests completed on 

unbound aggregate base materials were extracted from the LTPP database for similar 

aggregate base materials. However, no resilient modulus tests have been completed on 

aggregate base materials that have a similar gradation to the one listed in table 3. Most of 

the base material tested within the LTPP program represents a more dense material. 

Figure 8 shows the average test results from repeated load resilient modulus tests for 

aggregate base materials that are as close as possible – but have slightly more material 

passing the smaller sieve sizes. These average values included in figure 8 were used in 

the study for the crushed stone aggregate base material. 

Table 3 Gradation requirements for the 21 AA-MOD crushed aggregate base 

planned for use along I-96. 

Sieve Size 37.5 mm 25.0 mm 12.5 mm 2.36 mm 0.60 mm 0.075 mm 

Percent 

Passing, % 

100 80-100 40-70 15-35 5-20



3.4 Hot Mix Asphalt Mixtures 

Three hot mix asphalt (HMA) mixtures are planned for use along I-96; an HMA wearing 

course, an HMA leveling course, and an HMA base course (refer to figure 1). The elastic 

modulus of the HMA is an input parameter for both the M-E analysis methods used in 

this design study. Dynamic modulus tests are unavailable for the mixtures planned for 

use along I-96, and are not included in the LTPP database. Thus, the Witczak dynamic 

modulus regression equation embedded in the new M-E Pavement Design Guide was 

used to calculate the modulus for each HMA mixture. 

Figures 9 to 11 show the average modulus at the mid-depth of each HMA layer. These 

monthly values at various depths were used in the new M-E Pavement Design Guide 

software. However, an equivalent annual modulus for each layer was used with the 

simplistic M-E analysis method. These resulting equivalent annual modulus values are 

provided in Appendix C. 

Dynamic Modulus, ksi 

3500 

3000 

2500 

2000 

1500 

1000 

500 

0 

0 5 10 15 

Month of Year 

Figure 9 Monthly average dynamic modulus values calculated at the mid-depth 

of the HMA wearing surface and leveling layers. 

The HMA mixtures are assumed to have minimum fracture characteristics. Figure 12 

graphically illustrates the minimum tensile strains at failure as a function of the resilient 

modulus measured using indirect tensile testing methods in accordance with the 

procedure recommended by Von Quintus, et al. (12) The fatigue cracking criteria used in 

the design study corresponds to the relationship in figure 12. The evaluation of fatigue 

cracking for the HMA layers was completed in accordance with the steps outlined by 

Von Quintus, et al., and Von Quintus and Killingsworth. (10,12) 

11




3500 

3000 

2500 

2000 

1500 

1000 

500 

0 

0 5 10 15 



of the upper portion of the HMA base layer. 


3500 

3000 

2500 

2000 

1500 

1000 

500 

0 

0 5 10 15 



of the lower portion of the HMA base layer. 

12



Tensile Strain at Failure, mils/in. 

100 

10 

1 

10 100 1000 10000 

Total Resilient Modulus, psi 

Figure 12 Relationship between minimum tensile failure strains and indirect 

tensile resilient modulus. (12) 

3.5 Subsurface Drainage System 

A subsurface drainage system was included in the proposed design for I-96. The 

subsurface drainage system ensures that the non-frost susceptible sand subbase and soils 

will not become saturated for extended periods of time. This recommendation and design 

feature is based on information recovered from boring logs and reported by Michigan 

DOT for the supporting soils in adjacent areas along I-96. 

4. Mechanistic-Empirical Thickness Design-Evaluation Method 

Two M-E analysis procedures were used to evaluate the design resulting from the 

AASHTO DARWin program (refer to figure 1). One is defined as the simplistic M-E 

procedure and the other is the new M-E Pavement Design Guide. Appendix C includes 

the response computations for the simplistic M-E procedure, while Appendix D provides 

the results of the evaualtion using the new M-E Pavement Design Guide software. This 

section of the report provides a summary of the results from the simplistic and new M-E 

analysis procedures. 

The structural deterioration of flexible pavements is associated with cracking of the HMA 

surface, and/or development of ruts in the wheel path. The methodology used in this 

13



study, applies the cumulative damage concept in the prediction of these two modes of 

distress. Use of the cumulative damage concept permits accounting, in a rational manner, 

for damage caused by each load application. 

Seasonal and other variations in material properties and modulus of each layer with 

different loads can be considered in these predictions of damage. Evaluations of design 

life for candidate pavement structures are based on computations of damage caused by 

each truck type and load (or an 18-kip ESAL) for different seasons of the year, and 

summing the results to obtain the total damage to the pavement structure. For this design 

study, however, dynamic modulus tests results were unavailable for all HMA mixtures 

planned for use along I-96. As noted above, the dynamic modulus for the HMA mixtures 

were calculated using the Witczak regression equation included in the new M-E 

Pavement Design Guide software. An equivalent annual modulus for similar HMA 

mixtures was used in the design study. The equivalent annual modulus values are 

included in Appendix C. 

4.1 Pavement Structural Evaluation Assumptions 

The pavement layer thickness and material types were based on mechanistic-empirical 

techniques, in accordance with the following assumptions and design features. 

• The pavement structural response model used to calculate pavement responses 

for the simplistic M-E analysis method was based on elastic layer theory - 

EVERSTRS. 

• The proposed pavement structure was evaluated using the design criteria for 

fatigue cracking (limiting the tensile strain at the bottom of the HMA layers), 

HMA rutting (limiting the vertical strain at the mid-depth of each HMA 

layer), and subgrade distortion (limiting the vertical strain at the top of the 

foundation soil). 

• Structural design life = 20 years. 

• Tire load = 4,500 lbs. (20 kN) per tire. 

• Tire pressure = 120 psi (827 kPa). 

• Sand Subbase; Assumed to be non-frost susceptible and determined from 

repeated load resilient modulus tests included in the LTPP database, figure 7; 

Poisson’s ratio = 0.40. 

• Aggregate Base (21AA-MOD); Determined from repeated load resilient 

modulus tests included in the LTPP database, figure 8; Poisson’s ratio = 0.35. 

• The combined equivalent annual elastic layer modulus for the HMA surface, 

leveling, and base mixtures = 892,000 psi (127.6 MPa) for the simplistic M-E 

analysis method, refer to Appendix C; Poisson’s ratio = 0.30. For the new M- 

E Pavement Design Guide, the dynamic modulus default values for a 

Superpave mix with a PG 70-22 asphalt was used (figures 9-11). The asphalt 

grades included as defaults in the new M-E Design Guide software are only 

for the standard grades. 

14



4.2 Evaluation Criteria 

The objective of this study was to evaluate the flexible pavement structure shown in 

figure 1 using M-E criteria over two analysis periods: 20 and 40 years. The failure of a 

pavement system under the cumulative damage concept is assumed to occur when the 

damage index reaches a fixed amount, generally 1.0. It should be understood that a 

damage index of 1.0 does not necessarily imply a functional failure, but is instead that 

level of damage selected as sufficient to warrant maintenance and/or rehabilitation. 

Failure of flexible pavements is defined as alligator cracking over 10 to 20 percent of the 

area subjected to wheels or one-half inch (12.7 mm) of foundation rutting. 

For this study, a damage index of 1.0 means the pavement has been subjected to a 

sufficient number of wheel loads (Nf) to cause 10 to 20 percent alligator cracking of 

moderate to high severity or 0.5 inches (12.7 mm) of foundation distortion. In addition, a 

value of 0.40 inches (10 mm) of distortion (rutting, ∆HMA) in the HMA layers was also 

used in the evaluation. These values of 10 to 20 percent cracking and 0.5 inches (12.7 

mm) of foundation distortion were selected, because previous studies of in-service 

pavements have indicated that these levels will usually trigger some type of pavement 

rehabilitation. 

4.3 Simplistic M-E Analysis Method 

Fatigue Cracking Evaluation 

Two fatigue cracking models were used with the simplistic M-E analysis method. 

Equation 1 and figure 13 were used to determine the allowable number of load 

applications for fatigue cracking analysis of the pavement structure. 

Where: 

−3. 

291 −0. 

854 

( Fatigue) 

= 0. 

00432( 

C)( 

) ( E) 

N t 

f ε (1) 

( ) M 

C = 10 

(2) 

⎛ Vbe 

M = 4. 

84 

⎜ 

⎝Va 

+ Vbe 

⎞ 

− 0. 

69 

⎟ 

⎠ 

(3) 

εt = Tensile strain at the bottom of the HMA layer, in./in. 

E = HMA elastic or dynamic modulus, psi. 

C = Correction factor to account for volumetric properties 

Vbe = Percent effective asphalt content by volume in HMA mixture, % 

Va = Percent air voids in the HMA mixture, % 

Equation 1 is based on 20 percent fatigue cracking, and is the equation embedded in the 

new M-E Pavement Design Guide software, but without the global calibration factors. 

The global calibration factors were not used because they were determined based on the 

cracking predictions using the modulus values of each layer within specific time intervals 

and seasons. The simplistic M-E method uses equivalent annual modulus values for each 

15



layer, which are presented and discussed in Appendix C. Figure 13 presents the 

allowable number of load applications for 10 percent cracking. Table 4 summarizes the 

allowable or permissible tensile strain at the bottom of the HMA layer for both the 20 and 

40-year traffic levels using both fatigue cracking relationships. 

The tensile strain at the bottom of the HMA layers was computed with EVERSTRS for 

the AASHTO design, which is also included in table 4 (refer to Appendix C). As shown, 

the computed tensile strain is less than the permissible HMA tensile strains for both 

fatigue cracking models. In fact, the computed tensile strain of 49.7 micro-strains is 

below the assumed endurance limit for HMA. Typical values being used for the 

endurance limit are in the range of 65 to 75 micro-strains. Thus, fatigue cracking should 

not be a problem for the proposed structure. 

Asphalt Concrete Tensile Strain, in/in 

Figure 13 Relationship between HMA tensile strain and allowable wheel load 

applications for the alligator cracking failure criteria. (8) 

Distortion Evaluation – Unbound Layers 

Equation 4 and figure 14 were used to determine the allowable number of load 

applications for distortion analyses of the unbound layers in the pavement structure. 

f 

0.0100 

0.0010 

0.0001 

1,000 10,000 100,000 1,000,000 10,000,000 

Wheel Load Applications 

−11 

0. 

955 

( Distortion) 

= 1. 

259x10 

( M R ) v( 

Soil ) 

16 

Asphalt Concrete Modulus 

−4. 

082 ( ) 

1,000,000 psi 

600,000 psi 

300,000 psi 

100,000 psi 

N ε (4)



Where: 

MR = Resilient modulus of the foundation soil, psi. 

εv(Soil) = Vertical strain at the top of the foundation soil, in./in. 

Table 4 summarizes the allowable or permissible vertical strain at the top of the sand 

subbase and foundation soil for both the 20 and 40-year traffic levels. The vertical strains 

at the top of the sand subbase and foundation soil were computed with EVERSTRS for 

the AASHTO design, which are also included in table 4 (refer to Appendix C). As 

shown, the computed vertical strains are significantly less than the permissible vertical 

strains for both layers. Thus, distortion in the unbound layers should not be a problem for 

the proposed structure. 

Table 4 Limiting criteria that were used to evaluate the design layer thickness 

(refer to figure 1) for a 20 and 40-year analysis periods. 

Design Criteria 

Limiting or Permissible 

Values 

20-Year 40-Year 

Analysis Analysis 

17 

Computed 

Responses 

(See Note 1) 

Design 80-kN (18-kip) ESALs 22,694,400 56,000,000 --- 

Equation 1; 

Tensile strain at the 

20% Cracking 

bottom of the HMA 

Figure 13; 

layers, in./in. 

10% Cracking 

Vertical Strain in the HMA layers, 

in./in. 

Vertical strain at the top of the nonfrost 

susceptible sand material, in/in. 

Vertical strain at the top of the 

foundation soil, in./in. 

Permissible maximum surface 

deflection, in. 

Unbound layer modulus ratios 

0.000100 0.000075 

0.000070 0.000053 

0.0000497 

0.000091 0.000068 0.00009196* 

0.000284 0.000227 0.0000993 

0.000235 0.000187 0.0000889 

0.0175 0.0158 0.0108 

Material and Thickness 

Dependent, but



Subgrade Vertical Compressive Strain, in/in 

Figure 14 Relationship between subgrade vertical strain and allowable wheel 

load applications for the foundation deformation failure criteria. (9) 

Rutting Evaluation – HMA Layers 

Equation 5 was used to calculate the expected rutting within the HMA layers (∆HMA) of 

the pavement structure and the permissible vertical strain in the HMA so that the rut 

depth in the HMA layers does not exceed 0.40 inches (10 mm). 

HMA 

0.0100 

0.0010 

0.0001 

1,000 10,000 100,000 1,000,000 10,000,000 

W heel Load Applications 

2. 

5896 1. 

0057 0. 

5213 0. 

4289 

( T ) ( Vbe 

) ( Va 

) ( N ) ( c f ) v( 

HMA) 

18 

Subgrade Modulus 

20,000 psi 

10,000 psi 

6,000 psi 

3,000 psi 

2,000 psi 

( )( t ) 

−7 

∆ = 5. 

37x10 

ε 

(5) 

Where: 

T = Mid-depth temperature of the HMA layer thickness increment, in. 

εv(HMA) = Vertical strain at the mid-depth of the HMA layer thickness increment, 

in./in. 

cf = Confinement factor 

tHMA = Thickness of the HMA increment, inches 

Table 4 summarizes the allowable or permissible vertical strain at the mid-depth of the 

HMA surface layers for both the 20 and 40-year traffic levels. The vertical strains at the 

mid-depth of the HMA surface layers were computed with EVERSTRS for the AASHTO 

design, which are also included in table 4 (refer to Appendix C). As shown, the 

HMA



computed vertical strain is greater than the permissible vertical strain. The rutting 

calculated with equation 5 is 0.48 inches (12 mm) for the 20-year traffic and 0.70 inches 

(18 mm) for the 40-year traffic. Thus, the simplistic M-E method suggests that rutting in 

the HMA layers is expected to require the pavement to be rehabilitated within the 

analysis period. 

Other Evaluation Criteria 

Two other criteria were used for the simplistic M-E thickness design check or evaluation. 

One is based on limiting the maximum surface deflection and the other is based on 

limiting the modulus ratio between two adjacent unbound pavement layers (figure 15). 

The long-term in place modulus of unbound base and subbase layers are dependent on the 

modulus of the supporting layer because of potential de-compaction in the lower portion 

of these layers. The Corp of Engineers developed criteria to limit the modulus of 

unbound aggregate layers based on the thickness of that layer and the modulus of the 

supporting layer. (9) This limiting modulus ratio criteria (figure 15) was used in 

determining the limiting modulus of the unbound aggregate base and subbase layers. The 

elastic layer modulus used in the design computations with EVERSTRS for the unbound 

layers are less than those that would result from using figure 15, because the actual stress 

sensitivity was used in determining those values. 

The permissible surface deflection is listed in table 4 for the two traffic levels or analysis 

periods. This permissible deflection criteria has been used by Von Quintus and 

Killingsworth and others in analyzing the performance of in-service pavements. (10,11) 

Table 4 also includes the maximum surface deflection computed with EVERSTRS (refer 

to Appendix C). As shown, the computed value is less than the permissible value. 

4.4 New M-E Pavement Design Guide Software 

The new M-E Pavement Design Guide software was used to evaluate the proposed 

pavement cross section designed using the AASHTO DARWin program. The inputs 

used in the program were the best available data and the global default values were used 

when insufficient data were available. Appendix D includes a summary of the inputs 

used and predicted distresses over time. A 30-year analysis period was used in the 

problem rather than 40 years, because the program became unstable above 30 years. 

In summary, the proposed flexible pavement and HMA mixtures are not expected to 

exhibit significant levels of distress, with the exception of rutting. The new M-E 

Pavement Design Guide software predicts greater levels of rutting in the unbound 

materials, especially in the foundation soil. One reason for this result is that most of the 

sites used in the calibration process for the new software have resilient modulus values 

for the subgrade and unbound base layers much greater than those used in this designevaluation 

study. 

19



Modulus of Layer n, 10 psi 

3 

100 

10 

1 

BASE COURSES 

(Meter = Inch x .0254) SUBBASE COURSES 

6" 

THICKNESS 

4" 

10" 

8" 

7" 

6" 

5" 

4" 

1 10 100 

Modulus of Layer n + 1, 10 psi 

10 5 psi = 698 MPa 

Figure 15 Limiting modulus criteria of unbound aggregate base and subbase 

layers. (9) 

20



5. Summary of Evaluations 

Table 5 provides a summary of all distresses predicted with the different M-E analysis 

methods used in this study. In summary, the pavement design cross section proposed for 

the reconstruction of I-96 is adequate relative to cracking. The one concern is with 

rutting and distortion. 

The new M-E Pavement Design Guide software predicts most of the distortion in the 

unbound layers and foundation soil, while the simplistic M-E analysis method predicts 

that most of the rutting will occur in the HMA layers. As noted in the previous section, it 

is believed that the rutting is being over predicted in the foundation soil with 14 inches of 

HMA and 16 inches of a crushed aggregate base. In addition, this segment of I-96 has a 

much higher traffic level than most of the LTPP sections that were used in the calibration 

of the new M-E Pavement Design Guide have much less traffic. For this reason, it is 

believed that most of the rutting will be in the HMA mixtures. 

Table 5 Summary of distresses predicted for the two analysis periods using the 

two M-E analysis methods. 

Predicted Distress 

Simplistic M-E Method 

New M-E Pavement 

Design Guide Software 

20-Year 40-Year 20-Year 40-Year 

Fatigue 

Damage 

Index 

0.324 

(0.101)* 

0.801 

(0.249)* 

0.028 0.047 

Cracking Area 

Cracking, % 

2 

(0)* 

6 

(1)* 

8.4 11.9 

Top-Down Cracking, ft./mi. NA NA 267 274 

Thermal Cracking, ft./mi. NA NA 40 211 

Total Rutting, PG 70-22 0.48 0.70 0.77 0.86 

inches PG 76-22 0.36 0.54 NA NA 

Layer Rutting PG 70-22 0.48 0.70 0.21 0.26 

or Distortion, 

inches 

Unbound 

Layers 

Minimal Minimal 0.56 0.60 

IRI, in./mi. NA NA 120 134 

*Note 1: The values in () for fatigue cracking are for the predictions using figure 13, while the 

other fatigue cracking numbers are based on equation 1. 

Note 2: The cells that are shaded or highlighted in the table exceed the allowable or permissible 

distress magnitudes at the end of each analysis period. 

An additional structure was analyzed to reduce the rutting in the HMA layers. The only 

difference between the proposed AASHTO-designed flexible pavement and other 

structure is that a PG 76-22 was included in the top two HMA layers (wearing surface 

and leveling course). The comparison of the predicted rutting for the two asphalts is 

21



shown in figure 16 and included in table 5. Using the stiffer asphalt will reduce rutting to 

an acceptable level, even for the 40-year analysis period. 

Rut Depth, inches 

0.8 

0.7 

0.6 

0.5 

0.4 

0.3 

0.2 

0.1 

0 

PG 76-22 PG 70-22 

0 10 20 30 40 50 

22 

Age, Years 

Figure 16 Comparison of predicted rutting for HMA mixtures with a PG 70-22 

and a PG 76-22. 

As shown in figure 1, a PG 70-22 asphalt is planned for use in the top two HMA layers. 

Whether the dynamic modulus regression equation will adequately estimate the stiffness 

values for the PG 70-22P mixtures is questionable. Whether a PG 70-22P or PG 76-22 is 

used should be defined based on asphalt or mixture modulus testing or some type of 

torture test to ensure that the HMA mixtures will be resistant to rutting. Without any 

additional mixture testing, it is suggested that a PG 76-22 asphalt be included in the top 

two mixtures. In addition, it should be confirmed that the pavement materials meet or 

exceed the assumptions used in design. It is also recommended that sufficient testing be 

completed during construction to ensure that the design assumptions are satisfied prior to 

construction. 

6. Limitations 

All work performed under this study was conducted in accordance with generally 

accepted pavement engineering practices using data and project information provided by 

the Mr. Curtis Bleech. No other warranty, express or implied, is made. The generalized



pavement thickness design recommendations presented herein were based upon the 

assumed subsurface and material conditions identified in the report. Sufficient testing 

should be completed during construction for quality control purposes and to confirm the 

design values assumed for this design study. 

7. References 

1. AASHTO, 1993 AASHTO Design Guide for Pavement Structures, American 

Association of State Highway and Transportation Officials, 1993. 

2. Von Quintus, Harold L., Pavement Structural Design Study – A Simplified Catalog of 

Solutions, Report No. 3065, Fugro-BRE, Inc. December 2001. 

3. NCHRP 1-37A, Mechanistic-Empirical Design Method for the Structural Design of 

New and Rehabilitated Pavement Structures, Final Report for NCHRP 1-37A, 

National Cooperative Highway Research Program, Washington, DC, 2004. 

4. Von Quintus, Harold and Amber Yau, Evaluation of Resilient Modulus Test Data in 

LTPP Database, Report No. FHWA/RD-01-158, Federal Highway Administration, 

Office of Infrastructure Research and Development, Washington, DC, 2001. 

5. Von Quintus, Harold and Amy Simpson, Documentation of the Back-Calculation o f 

Layer Parameters for LTPP Test Sections, Volume II: Layered Elastic Analysis for 

Flexible and Rigid Pavements, Final Report LTPP DATA, Work Order 9, Task 2 

Contract No. DTFH61-96-C-00003, Federal Highway Administration, U.S. 

Department of Transportation, January 1999. 

6. Von Quintus, Harold and Brian Killingsworth, Design Pamphlet for the 

Backcalculation of Pavement Layer Moduli, Publication No. FHWA-RD-97-076, 

Federal Highway Administration, Washington, D.C., June 1997. 

7. Soils and Geology – Pavement Design for Frost Conditions, TM5-818-2, Department 

of the Army Technical Manual, Headquarters, Department of the Army, July 1965. 

8. Finn, F.N., K. Nair, C. Monismith, Minimizing Premature Cracking of Asphalt 

Concrete Pavements, NCHRP Report No. 195, National Cooperative Highway 

Research Program, National Research Council, Washington, DC, June 1973. 

9. Barker, W. R. and W. N. Brabston, Development of a Structural Design Procedure 

for Flexible Airport Pavements, FAA Report No. FAA-RD-74-199, U.S. Army 

Engineer Waterways Experiment Station, Federal Aviation Administration, 

September 1975. 

23



10. Von Quintus, H. L. and Brian Killingsworth, Analyses Relating to Pavement Material 

Characterizations and Their Effects on Pavement Performance, Publication No. 

FHWA-RD-97-085, Federal Highway Administration, January 1998. 

11. Rauhut, J.B. R.L. Lytton, and M.I. Darter, Pavement Damage Functions for Cost 

Allocation, Volume 1: Damage Functions and Load Equivalence Factors, Publication 

No. FHWA/RD-84-018, Federal Highway Administration, Washington, DC, 1984. 

12. Von Quintus, H.L., J.A. Scherocman, C.S. Hughes and T.W. Kennedy, Asphalt- 

Aggregate Mixture Analysis System-AAMAS, NCHRP Report No. 338, National 

Cooperative Highway Research Program, National Research Council, Washington, 

DC, March 1991. 

24



Appendix A 

Summary of Truck Traffic Equivalent Single Axle Load Applications 

Computed for the Base Year 2005 

Appendix A includes a copy of the spreadsheet used to compute the number of 80-kN 

(18-kip) equivalent single axle loads for the base year using the default distributions that 

are included in the new M-E Pavement Design Guide for an urban freeway similar to I- 

96. 

As shown on the attached spreadsheet, the total number of annual ESALs for 2005 is 

4,411,425 for both directions. Using a directional distribution factor of 0.56 and a lane 

distribution factor of 0.70, the total number of annual ESALs in the design lane is 

1,729,279. The average truck equivalency factor for this truck traffic stream is 1.259 

ESAL per truck application. 

25



26



27



28



29



30



31



Appendix B 

Summary of Repeated Load Resilient Modulus Tests Extracted from 

the LTPP Database for the Michigan Sites. 

Distribution of Average resilient Modulus for GSGB (Sand). 

RES_MOD_AVG 

250 

200 

150 

100 

50 

Quantiles 

maximum 

quartile 

median 

quartile 

minimum 

Moments 

Mean 

Std Dev 

Std Error Mean 

Upper 95% Mean 

Lower 95% Mean 

N 

Sum Weights 

100.0% 

99.5% 

97.5% 

90.0% 

75.0% 

50.0% 

25.0% 

10.0% 

2.5% 

0.5% 

0.0% 

226.00 

226.00 

200.12 

151.70 

138.00 

127.00 

112.00 

103.30 

73.72 

72.00 

72.00 

126.7581 

24.4612 

3.1066 

132.9700 

120.5461 

62.0000 

62.0000 

Figure 17 Resilient modulus (in MPa) measured on sand base and subbase 

materials recovered from all sites in the LTPP program for a 

confining pressure of 10 psi (69 kPa) and a cyclic stress of 9 psi 

(62kPa). The resilient modulus values given above are in MPa. 

32



Distribution of Average resilient Modulus for GSGB (Sand) for Michigan sites. 

RES_MOD_AVG 

200 

180 

160 

140 

120 

100 

Quantiles 

maximum 

quartile 

median 

quartile 

minimum 

Moments 

Mean 

Std Dev 




N 

Sum Weights 

100.0% 

99.5% 

97.5% 

90.0% 

75.0% 

50.0% 

25.0% 

10.0% 

2.5% 

0.5% 

0.0% 

181.00 

181.00 

181.00 

178.10 

143.75 

129.00 

115.75 

114.10 

114.00 

114.00 

114.00 

133.2000 

21.1019 

6.6730 

148.2955 

118.1045 

10.0000 

10.0000 

Figure 18 Resilient modulus (in MPa) measured on sand base and subbase 

materials recovered from all Michigan sites included in the LTPP 

program for a confining pressure of 10 psi (69 kPa) and a cyclic stress 

of 9 psi (62 kPa). The resilient modulus values given above are in 

MPa. 

33



Distribution of Average resilient Modulus Subgrade Sand. 

RES_MOD_AVG 

200 

100 

Quantiles 

maximum 

quartile 

median 

quartile 

minimum 

Moments 

Mean 

Std Dev 




N 

Sum Weights 

100.0% 

99.5% 

97.5% 

90.0% 

75.0% 

50.0% 

25.0% 

10.0% 

2.5% 

0.5% 

0.0% 

191.00 

147.36 

111.87 

84.00 

67.00 

53.00 

43.00 

36.00 

28.00 

23.00 

18.00 

57.6341 

21.3246 

1.0166 

59.6321 

55.6360 

440.0000 

440.0000 

Figure 19 Resilient modulus (in MPa) measured on sand recovered from the 

subgrade at all sites in the LTPP program for a confining pressure of 

2.0 psi (13.8 kPa) and a cyclic stress of 1.8 psi (12.4 kPa). The resilient 

modulus values given above are in MPa. 

34



Distribution of Average resilient Modulus for Sugrade Sand for Michigan sites. 

RES_MOD_AVG 

200 

150 

100 

50 

Quantiles 

maximum 

quartile 

median 

quartile 

minimum 

Moments 

Mean 

Std Dev 




N 

Sum Weights 

100.0% 

99.5% 

97.5% 

90.0% 

75.0% 

50.0% 

25.0% 

10.0% 

2.5% 

0.5% 

0.0% 

191.00 

191.00 

191.00 

191.00 

63.00 

57.00 

50.00 

42.00 

42.00 

42.00 

42.00 

73.4286 

52.3477 

19.7856 

121.8422 

25.0150 

7.0000 

7.0000 

Figure 20 Resilient modulus (in MPa) measured on sand recovered from the 

subgrade at all Michigan sites included in the LTPP program for a 

confining pressure of 2.0 psi (13.8 kPa) and a cyclic stress of 1.8 psi 

(12.4 kPa). The resilient modulus values given above are in MPa. 

35



Appendix C 

Layer Properties and Pavement Responses Computed for the I-96 

Design Cross Section 

Appendix C includes a summary of the methods used to determine the elastic modulus 

values for each layer and a copy of the pavement responses that were used to evaluate the 

pavement structure. These responses were calculated with EVERSTRS for the standard 

design axle load – 18-kip single axle load. 

C.1 HMA Modulus Determination 

As noted in the report, the dynamic modulus regression equation was used to estimate the 

average modulus of each HMA mixture for each month of an average year. The first part 

of Appendix C includes the spreadsheet used to determine the monthly modulus values 

and the equivalent annual layer modulus for the HMA mixtures used in the fatigue 

cracking analysis. For the rutting analysis and predictions made with the simplistic M-E 

method, the elastic modulus for the three summer months was used. 

36



37



C.2 Unbound Layer Modulus Determination 

The second part of Appendix C includes a summary of the procedure and responses used 

to determine the resilient modulus for each unbound layer. In other words, select an 

elastic modulus for the unbound materials and soils to ensure that the theory 

(EVERSTRS) and laboratory provide consistent values at the same stress state for use in 

the fatigue analysis. 

One of the important steps in this process is to include the at-rest stresses with those 

computed from EVERSTRS. Table 6 provides a summary of the information and data 

that were used to compute the overburden pressures and at-rest stresses in each unbound 

layer. 

Table 6 Data used to calculate the overburden pressure and at-rest stresses in 

each unbound layer of the design cross section (refer to figure 1). 

Layer/Material Type 

Dry Density, 

pcf 

38 

Moisture 

Content, % 

At-Rest Earth Pressure 

Coefficient, ko 

HMA; average of all three 

layers 

150 --- --- 

21 AA-MOD Crushed 

Aggregate Base 

130 7.0 0.9 

Class II-A Sand Subbase 136 7.0 0.9 

Low Plasticity, Firm Silty 

Clay 

116 13.0 0.5 

Table 7 summarizes the EVERSTRS computations from two iterations of using trial 

elastic modulus values for each unbound layer. The two iterations demonstrate the need 

to check the values used in the elastic layer program to ensure that the theory and 

laboratory values provide consistent results. As summarized in table 7, the first iteration 

used the design resilient modulus suggested for use by the Michigan DOT and the 

maximum layer modulus ratio to estimate the elastic modulus of all other unbound layers 

(refer to figure 15). The trial or “guessed” resilient modulus values are not consistent 

with the values that would be measured in the laboratory from repeated load tests (figures 

5,7, and8). However, the modulus values used in the second iteration are, for all practical 

purposes the same values that would be measured in the laboratory at the same stress 

states. The values from the second iteration were used in the fatigue cracking analysis.



Table 7 Comparison of the trial elastic layer modulus used in EVERSTRS with those measured from repeated load 

resilient modulus tests in the laboratory at the same stress state. 

1 

2 

Iteration No. & 

Unbound Layer 

Trial E- 

Value, ksi 

At-Rest Stress @ ¼ 

Layer Depth, psi 

XX & 

ZZ 

YY 

Stresses Computed w/EVERSTRS @ 

¼ Layer Depth, psi 

ZZ XX YY 

39 

Confining 

Stress 

Total Stress State, psi 

Deviator 

Stress 

Bulk 

Stress 

Lab E- 

Value, ksi 

Silty Clay* 3 -4.55 -2.28 -0.30 -0.04 -0.04 2.32 2.53 --- 5.1 

Sand Subbase 9 -2.68 -2.41 -0.50 0.37 0.39 2.02 --- 7.24 6.8 

Aggregate Base 20 -1.54 -1.39 -1.21 0.42 0.51 0.88 --- 4.60 6.5 

Silty Clay* 5.2 -4.55 -2.28 -0.41 -0.07 -0.07 2.69 2.61 --- 5.2 

Sand Subbase 7.0 -2.68 -2.41 -0.64 0.02 0.04 2.37 --- 8.08 7.2 

Aggregate Base 7.5 -1.54 -1.39 -0.97 -0.11 -0.07 1.46 --- 5.47 7.5 

*NOTE: The stress state was determined at the ¼ depth within each unbound layer, with the exception for the foundation or subgrade soils. The stress state was 

determined 18-inches into the subgrade. These depths are consistent with the values recommended for use by Von Quintus, et al. (10) The at-rest stresses were 

computed using the information and data included in table 6.



C.3 EVERSTRS Output for Fatigue Cracking Analyses 

The following is a summary of the output from the EVERSTRS program for the design 

cross section using the layer modulus values determined in the previous section of 

Appendix C. The other pavement responses are also included in this ouput for 

determining the damage index for fatigue cracking and foundation distortion, and 

whether the design cross section will be provide adequate performance over the two 

analysis periods. These responses are based on equivalent annual modulus values. 

CLayered Elastic Analysis by EverStress for Windows 

Title: Michigan I-96 Reconstruction 

No of Layers: 

5 No of Loads: 2 No of X-Y Evaluation Points: 2 

Layer Poisson's Thickness Moduli(1) 

* Ratio (in) (ksi) 

1 0.3 14 892 

2 0.35 16 7.5 

3 0.35 8 7 

4 0.45 240 5.2 

5 0.4 * 50 

Load No X-Position Y-Position Load Pressure Radius 

* (in) (in) (lbf) (psi) (in) 

1 0 0 4500 120 3.455 

2 13 0 4500 120 3.455 

Location No: 

1 X-Position (in): .000 Y-Position (in): .000 

cNormal Stresses 

Z-Position Layer Sxx Syy Szz Syz Sxz Sxy 

(in) * (psi) (psi) (psi) (psi) (psi) (psi) 

13.999 1 49.55 56.79 -1.15 0 0.13 0 

18 2 -0.11 -0.07 -0.97 0 0.1 0 

32 3 0.02 0.04 -0.64 0 0.05 0 

38.1 4 -0.12 -0.11 -0.56 0 0.03 0 

56 4 -0.07 -0.07 -0.41 0 0.02 0 

cNormal Strains and Deflections 

Z-Position Layer Exx Eyy Ezz Ux Uy Uz 

(in) * (10^-6) (10^-6) (10^-6) (mils) (mils) (mils) 

13.999 1 36.83 47.39 -37.06 -0.246 0 10.163 

18 2 34.26 40.87 -121.13 -0.235 0 9.642 

32 3 33.55 35.68 -94 -0.224 0 8.197 

38.1 4 35.04 36.79 -87.08 -0.233 0 7.643 

56 4 28.26 29.03 -67.77 -0.186 0 6.268 

cPrincipal Stresses and Strains 

Z-Position Layer S1 S2 S3 E1 E2 E3 

(in) * (psi) (psi) (psi) (10^-6) (10^-6) (10^-6) 

13.999 1 -1.15 49.55 56.79 -37.06 36.83 47.39 

18 2 -0.98 -0.1 -0.07 -123.34 36.47 40.87 

32 3 -0.64 0.03 0.04 -94.71 34.26 35.68 

38.1 4 -0.56 -0.12 -0.11 -87.81 35.77 36.79 

56 4 -0.41 -0.07 -0.07 -68.11 28.6 29.03 

40



Location No: X-Position (in): 

2 

6.500 Y-Position (in): .000 




13.999 1 51.24 59.38 -1.19 0 0 0 

18 2 -0.1 -0.07 -1.01 0 0 0 

32 3 0.03 0.04 -0.65 0 0 0 

38.1 4 -0.12 -0.11 -0.57 0 0 0 

56 


4 -0.07 -0.07 -0.42 0 0 0 



13.999 1 37.87 49.74 -38.54 0 0 10.299 

18 2 36.9 42.51 -126.58 0 0 9.756 

32 3 34.99 36.22 -96.23 0 0 8.26 

38.1 4 36.26 37.23 -88.89 0 0 7.695 

56 


4 28.82 29.22 -68.58 0 0 6.299 


(in) * (psi) (psi) (psi) (10^-6) (10^-6) (10^-6) 

13.999 1 -1.19 51.24 59.38 -38.54 37.87 49.74 

18 2 -1.01 -0.1 -0.07 -126.58 36.9 42.51 

32 3 -0.65 0.03 0.04 -96.23 34.99 36.22 

38.1 4 -0.57 -0.12 -0.11 -88.89 36.26 37.23 

56 4 -0.42 -0.07 -0.07 -68.58 28.82 29.22 

41



C.4 EVERSTRS Output for HMA Rutting Analyses 

The output from the EVERSTRS program summarized below was used to calculate the 

expected rutting in the HMA layers using the average summer modulus values. 

CLayered Elastic Analysis by EverStress for Windows 

Title: Michigan I-96 Reconstruction 

No of Layers: 

5 No of Loads: 2 No of X-Y Evaluation Points: 2 

Layer Poisson's Thickness Moduli(1) 

* Ratio (in) (ksi) 

1 0.3 4 700 

2 0.35 10 615 

3 0.35 24 7.5 

4 0.45 240 5.2 

5 0.4 * 

Y- 

50 

Load No X-Position 

Position Load Pressure Radius 

* (in) (in) (lbf) (psi) (in) 

1 0 0 4500 120 3.455 

2 13 0 4500 120 3.455 

Location No: X-Position (in): 

1 

.000 Y-Position (in): .000 




1 1 -85.01 -89.89 -116.84 0 1.14 0 

3 1 -28.04 -28.95 -82.96 0 3.21 0 

5.2 2 -11.11 -9.67 -46.35 0 4.85 0 

7.7 2 4.15 6.63 -22.69 0 5.49 0 

11.5 


2 27.58 31.48 -5.29 0 3.59 0 



1 1 -32.84 -41.9 -91.96 0.235 0 12.081 

3 1 7.9 6.21 -94.09 0.134 0 11.881 

5.2 2 13.82 16.98 -63.54 0.041 0 11.708 

7.7 2 15.89 21.33 -43.02 -0.052 0 11.579 

11.5 


2 29.94 38.5 -42.21 -0.196 0 11.426 


(in) * (psi) (psi) (psi) (10^-6) (10^-6) (10^-6) 

1 1 -116.88 -89.89 -84.97 -92.03 -41.9 -32.77 

3 1 -83.15 -28.95 -27.86 -94.44 6.21 8.25 

5.2 2 -47.01 -10.45 -9.67 -64.98 15.26 16.98 

7.7 2 -23.77 5.23 6.63 -45.4 18.26 21.33 

11.5 2 -5.68 27.97 31.48 -43.06 30.79 38.5 

42



Appendix D 

Analysis of the Proposed Pavement Design Cross Section for I-96 Using 

the New M-E Pavement Design Guide Software 

Appendix D includes a listing of the inputs used in the new M-E Pavement Design Guide 

software. In addition, graphical summarizes of all predicted distresses follow the inputs. 

43



Project: I-96, Wayne County, Michigan 

General Information 

Design Life 30 years 

Base/Subgrade construction: September, 2003 

Pavement construction: September, 2003 

Traffic open: October, 2003 

Type of design Flexible 

Analysis Parameters 

Analysis type Probabilistic 

Performance Criteria 

Initial IRI (in/mi) 

Terminal IRI (in/mi) 

AC Surface Down Cracking (Long. Cracking) (ft/500): 

AC Bottom Up Cracking (Alligator Cracking) (%): 

AC Thermal Fracture (Transverse Cracking) (ft/mi): 

Permanent Deformation (AC Only) (in): 

Permanent Deformation (Total Pavement) (in): 

Description: 

This is an analysis of a flexible pavement design that 

was completed using the 1993 AASHTO DARWin 

procedure. 

44 

9600 

2 

56 

70 

45 

Limit Reliability 

65 

170 90 

2500 90 

10 90 

1000 90 

0.35 90 

0.6 90 

Location: I-96; Wayne County, Michigan 

Project ID: CS 82122 

Section ID: M-39 to Schaefer Road 

Principal Arterials - Interstate and Defense Routes 

Date: 8/26/2004 

Station/milepost format: Miles: 0.000 

Station/milepost begin: 11.72 

Station/milepost end: 12.05 

Traffic direction: East bound 

Default Input Level 

Default input level Level 3, Default and historical agency values. 

Traffic 

Initial two-way aadtt: 

Number of lanes in design direction: 

Percent of trucks in design direction (%): 

Percent of trucks in design lane (%): 

Operational speed (mph): 

Traffic -- Volume Adjustment Factors 

Monthly Adjustment Factors (Level 3, Default MAF) 

Month 

January 

February 

March 

April 

May 

June 

July 

August 

September 

October 

November 

December 

Vehicle Class 

Class 4 Class 5 Class 6 Class 7 Class 8 Class 9 Class 10 Class 11 Class 12 Class 13 

1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00



Vehicle Class Distribution Hourly truck traffic distribution 

(Level 3, Default Distribution) by period beginning: 

AADTT distribution by vehicle class 

Midnight 1.2% Noon 3.5% 

Class 4 0.9% 1:00 am 0.6% 1:00 pm 4.2% 

Class 5 11.6% 2:00 am 0.5% 2:00 pm 6.1% 

Class 6 3.6% 3:00 am 0.5% 3:00 pm 7.3% 

Class 7 0.2% 4:00 am 0.6% 4:00 pm 7.1% 

Class 8 6.7% 5:00 am 2.3% 5:00 pm 9.8% 

Class 9 62.0% 6:00 am 8.0% 6:00 pm 6.4% 

Class 10 4.8% 7:00 am 7.9% 7:00 pm 4.0% 

Class 11 2.6% 8:00 am 7.4% 8:00 pm 3.0% 

Class 12 1.4% 9:00 am 4.5% 9:00 pm 2.8% 

Class 13 6.2% 10:00 am 3.9% 10:00 pm 2.3% 

11:00 am 4.1% 11:00 pm 2.0% 

Traffic Growth Factor 

Vehicle Growth Growth 

Class Rate Function 

Class 4 2.0% Compound 










Traffic -- Axle Load Distribution Factors 

Level 3: Default 

Traffic -- General Traffic Inputs 

Mean wheel location (inches from the lane 

marking): 

Traffic wander standard deviation (in): 

Design lane width (ft): 

Number of Axles per Truck 

Vehicle 

Class 

Class 4 

Class 5 

Class 6 

Class 7 

Class 8 

Class 9 

Class 10 

Class 11 

Class 12 

Class 13 

18 

10 

12 

Single Tandem Tridem Quad 

Axle Axle Axle Axle 

1.62 0.39 0.00 0.00 

2.00 0.00 0.00 0.00 

1.02 0.99 0.00 0.00 

1.00 0.26 0.83 0.00 

2.38 0.67 0.00 0.00 

1.13 1.93 0.00 0.00 

1.19 1.09 0.89 0.00 

4.29 0.26 0.06 0.00 

3.52 1.14 0.06 0.00 

2.15 2.13 0.35 0.00 

Axle Configuration 

Average axle width (edge-to-edge) outside 

dimensions,ft): 

Dual tire spacing (in): 

Axle Configuration 

Single Tire (psi): 

Dual Tire (psi): 

Average Axle Spacing 

Tandem axle(psi): 

Tridem axle(psi): 

Quad axle(psi): 

8.5 

12 

120 

120 

51.6 

49.2 

49.2 

45



Climate 

icm file: 

Latitude (degrees.minutes) 

Longitude (degrees.minutes) 

Elevation (ft) 

Depth of water table (ft) 

Structure--Design Features 

Detroit-Michigan 

42.13 

-83.21 

628 

10 

Structure--Layers 

Layer 1 -- Asphalt concrete 

Material type: Asphalt concrete 

Layer thickness (in): 1.5 

General Properties 

General 

Reference temperature (F°): 70 

Volumetric Properties as Built 

Effective binder content (%): 10.5 

Air voids (%): 7.5 

Total unit weight (pcf): 148 

Poisson's ratio: 0.35 (predicted) 

Parameter a: -1.63 

Parameter b: 0.00000384 

Thermal Properties 

Thermal conductivity asphalt (BTU/hr-ft-F°): 0.67 

Heat capacity asphalt (BTU/lb-F°): 0.23 

Asphalt Mix 

Cumulative % Retained 3/4 inch sieve: 0 


Cumulative % Retained #4 sieve: 35 

% Passing #200 sieve: 6.5 

Asphalt Binder 

Option: Superpave binder grading 

A 10.2990 (correlated) 

VTS: -3.4260 (correlated) 

High temp. 

°C 

46 

52 

58 

64 

70 

76 

82 

Low temperature, °C 

-10 -16 -22 -28 -34 -40 -46 

46





Layer thickness (in): 2.5 


General 












Asphalt Mix 




% Passing #200 sieve: 6 





High temp. 

°C 

46 

52 

58 

64 

70 

76 

82 


-10 -16 -22 -28 -34 -40 -46 

47





Layer thickness (in): 10 


General 












Asphalt Mix 




% Passing #200 sieve: 5.5 





High temp. 

°C 

46 

52 

58 

64 

70 

76 

82 


-10 -16 -22 -28 -34 -40 -46 

48



Layer 4 -- Crushed gravel 

Unbound Material: Crushed gravel 

Thickness(in): 16 

Strength Properties 

Input Level: Level 3 

Analysis Type: ICM inputs (ICM Calculated Modulus) 

Poisson's ratio: 0.35 

Coefficient of lateral pressure,Ko: 0.5 

Modulus (input) (psi): 7500 

ICM Inputs 

Gradation and Plasticity Index 

Plasticity Index, PI: 0 

Passing #200 sieve (%): 7 


D60 (mm): 10 

Calculated/Derived Parameters 

Maximum dry unit weight (pcf): 130 (user input) 

Specific gravity of solids, Gs: 2.65 (derived) 

Saturated hydraulic conductivity (ft/hr): 302 (derived) 

Optimum gravimetric water content (%): 7 (user input) 

Calculated degree of saturation (%): 78 (calculated) 

Soil water characteristic curve parameters: Default values 

Parameters 

a 

b 

c 

Hr. 

Value 

0.153 

7.5 

1.18 

0.015 

Layer 5 -- A-2-4 

Unbound Material: A-2-4 








ICM Inputs 





D60 (mm): 0.1 




Saturated hydraulic conductivity (ft/hr): 0.000866 (derived) 


Calculated degree of saturation (%): 78 (calculated) 


Parameters 

a 

b 

c 

Hr. 

Value 

4.86 

7.5 

0.365 

17.5 

49



Layer 6 -- CL 

Unbound Material: CL 








ICM Inputs 





D60 (mm): 0.1 




Saturated hydraulic conductivity (ft/hr): 3.25e-005 (derived) 


Calculated degree of saturation (%): 87.4 (calculated) 


Parameters 

a 

b 

c 

Hr. 

Value 

57.5 

1.18 

0.648 

2240 

Layer 7 -- CL 

Unbound Material: CL 

Thickness(in): Semi-infinite 







ICM Inputs 





D60 (mm): 0.1 




Saturated hydraulic conductivity (ft/hr): 3.25e-005 (derived) 


Calculated degree of saturation (%): 87.4 (calculated) 


Parameters 

a 

b 

c 

Hr. 

Value 

57.5 

1.18 

0.648 

2240 

50



Distress Model Calibration Settings - Flexible 

AC Fatigue Level 3 (Nationally calibrated values) 

k1 

0.00432 

k2 

3.9492 

k3 

1.281 

AC Rutting Level 3 (Nationally calibrated values) 

k1 

k2 

k3 

Standard Deviation Total 

Rutting (RUT): 

-3.4488 

1.5606 

0.4791 

Thermal Fracture Level 3 (Nationally calibrated values) 

k1 

5 

1 

1 

7 

3.5 

0 

1000 

1 

1 

0 

6000 

1 

1 

0 

1000 

IRI 

IRI Flexible Pavements with GB 

C1 (GB) 

0.0463 

C2 (GB) 

0.00119 

C3 (GB) 

0.1834 

C4 (GB) 

0.00384 

C5 (GB) 

0.00736 

C6 (GB) 

0.00115 

Std. Dev (GB) 

0.387 

0.1587*POWER(RUT,0.4579)+0.001 

Std. Dev. (THERMAL): 0.2474 * THERMAL + 10.619 

CSM Fatigue Level 3 (Nationally calibrated values) 

k1 

k2 

Subgrade Rutting Level 3 (Nationally calibrated values) 

Granular: 

k1 

1.673 

Fine-grain: 

k1 

1.35 

AC Cracking 

AC Top Down Cracking 

C1 (top) 

C2 (top) 

C3 (top) 

C4 (top) 

Standard Deviation (TOP) 200 + 2300/(1+exp(1.072-2.1654*log(TOP+0.0001))) 

AC Bottom Up Cracking 

C1 (bottom) 

C2 (bottom) 

C3 (bottom) 

C4 (bottom) 

Standard Deviation (TOP) 32.7 + 995.1 /(1+exp(2-2*log(BOTTOM+0.0001))) 

CSM Cracking 

C1 (CSM) 

C2 (CSM) 

C3 (CSM) 

C4 (CSM) 

Standard Deviation (CSM) CTB*1 

IRI Flexible Pavements with ATB 

C1 (ATB) 

C2 (ATB) 

C3 (ATB) 

C4 (ATB) 

0.009995 

0.000518 

0.00235 

18.36 

51



The following graphs represent the distress predictions with the new M-E Pavement Design Guide software. 

Longitudinal Cracking (ft/mi) 

Alligator Cracking (%) 

3000 

2700 

2400 

2100 

1800 

1500 

1200 

900 

600 

300 

100 

90 

80 

70 

60 

50 

40 

30 

20 

10 

0 

Surface Down Cracking - Longitudinal 

0 

0 36 72 108 144 180 216 252 288 324 360 396 

Pavement Age (month) 

Bottom Up Cracking - Alligator 

0 36 72 108 144 180 216 252 288 324 360 396 


52 

Surface 

Depth = 0.5" 

Surface at Reliability 

Design Limit 

Maximum Cracking 

Bottom Up Reliability 

Maximum Cracking Limit



Total Length (ft/mi) 

Rutting Depth (in) 

2000 

1800 

1600 

1400 

1200 

1000 

800 

600 

400 

200 

1.20 

1.00 

0.80 

0.60 

0.40 

0.20 

0.00 

Thermal Cracking: Total Length Vs Time 

0 

0 36 72 108 144 180 216 252 288 324 360 396 

AC Rutting Design Value = 0.35 

Total Rutting Design Limit = 0.6 


Permanant Deformation: Rutting 

0 36 72 108 144 180 216 252 288 324 360 396 


53 

Thermal Crack Length 

Crack Length at Reliability 

Design Limit 

SubTotalAC 

SubTotalBase 

SubTotalSG 

Total Rutting 

TotalRutReliability 

Total Rutting Design Limit



IRI (in/mi) 

200 

180 

160 

140 

120 

100 

80 

60 

40 

20 

0 

0 36 72 108 144 180 216 252 288 324 360 396 

IRI 


54 

IRI 

IRI at Reliability 

Design Limit

Pavement Structural Analysis of the Design Recommendations for ...

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