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Publication Number: FHWA-HRT-05-079
Date: May 2006

Optimization of Traffic Data Collection for Specific Pavement Design Applications

Appendix C. Structural And Climatic Input

This Appendix lists the structural and climatic input values used for the 2002 Pavement Design Guide (PDG) for the detailed sensitivity analysis LTPP sites. The structural input is listed in the order in which it is entered into the PDG.

Structure: Jointed Portland Cement Concrete Pavement

  1. Design features
    1. Slab thickness: Variable (table 9)
    2. Permanent curl/warp effective temperature difference: 23.3 degrees Celsius (°C) (75 degrees Fahrenheit (°F))
    3. Joint spacing: 3.7 m (12 ft)
    4. Sealant type: Liquid
    5. Doweled transverse joints
    6. Dowel diameter: 32 mm (1.25 inches)
    7. Dowel bar spacing: 305 mm (12 inches)
    8. Edge support: None
    9. Base type: Granular
    10. PCC-base interface: Bonded
    11. Erodibility index: Erosion resistant (3)
    12. Loss of bond age (months): 60
  2. Drainage and surface properties
    1. Surface shortwave absorptivity: 0.85
    2. Infiltration: Minor (10 percent)
    3. Drainage path length: 3.7 m (12 ft)
      1. Pavement cross slope (percent): 2
  3. Layers
    1. PCC
      1. Thermal
        1. PCC material: JPCP
        2. Layer thickness: Variable (table 9)
        3. Unit weight: 2400 kilograms per cubic meter (kg/m3) (159 pounds per cubic foot (lb/ft3)
        4. Poisson's ratio: 0.20
        5. Coefficient of thermal expansion: 9.9 x 10-6 °C-1 (5.5 x 10-6 °F-1)
        6. Thermal conductivity: 2.16 watts (W)/m-°C (1.25 British thermal units (BTU)/h-ft-°F)
        7. Heat capacity: 0.33 W-h/kg-°C (0.28 BTU/lb-°F)
      2. Mix
        1. Cement type: Type II
        2. Cementitious material content: 178 kg/m3 (600 pounds per cubic yard (lb/yd3))
        3. Water-cement ratio: 0.4
        4. Aggregate type: Gabbro
        5. PCC zero-stress temperature (°F): Computed by PDG
        6. Ultimate shrinkage at 40 percent relative humidity (RH) (microstrain): Computed by PDG
        7. Reversible shrinkage (percent of ultimate shrinkage): Computed by PDG
        8. Time to develop 50 percent of ultimate shrinkage (days): Computed by PDG
        9. Curing method: Curing compound
      3. Strength: Level 2 (table C.1)

 

Table 35. PC strength properties for level 2 input.
Time Compressive Strength (kilopascals (kPa)) Compressive Strength (pounds force per square inch (lbf/inch2))
7 days 24,500 3560
14 days 26,900 3900
28 days 29,000 4200
90 days 32,500 4700
20 years/28 days   1.44

Structure: Continuously Reinforced Concrete Pavement

  1. Design features
    1. Slab thickness: Variable (table 9)
    2. Shoulder type: Asphalt
      1. Permanent curl/warp effective temperature difference: 23.3 °C (-10 °F)
    3. Steel reinforcement
      1. Percent steel (percent): 0.7
      2. Bar diameter: 16 mm (0.625 inch)
      3. Steel depth: 356 mm (4 inches)
    4. Base properties
      1. Base type: Granular
      2. Erodibility index: Erosion resistant (3)
      3. Base/slab friction coefficient: 4
    5. Crack spacing: Generate using model
  2. Drainage and surface properties
    1. Surface shortwave absorptivity: 0.85
    2. Infiltration: Minor (10 percent)
    3. Drainage path length: 3.7 m (12 ft)
      1. Pavement cross slope (percent): 2
  3. Layers
    1. PCC
      1. Thermal
        1. PCC material: CRCP
        2. Layer thickness: Variable (table 9)
        3. Unit weight: 2400 kg/m3 (150 lb/ft3)
        4. Poisson's ratio: 0.20
        5. Coefficient of thermal expansion: 9.9 x 10-6 °C-1 (5.5 x 10-6 °F-1)
        6. Thermal conductivity: 2.16 W/m-°C (1.25 BTU/h-ft-°F)
        7. Heat capacity: 0.33 W-h/kg-°C (0.28 BTU/lb-°F)
      2. Mix
        1. Cement type: Type II
        2. Cementitious material content: 178 kg/m3 (600 lb/yd3)
        3. Water-cement ratio: 0.4
        4. Aggregate Type: Gabbro
        5. PCC zero-stress temperature (°F): Computed by PDG
        6. Ultimate shrinkage at 40 percent RH (microstrain): Computed by PDG
        7. Reversible shrinkage (percent of ultimate shrinkage): Computed by PDG
        8. Curing method: Curing compound
      3. Strength: Level 2 (table 35)

Structure: Asphalt Concrete Pavement

  1. Drainage and surface properties
    1. Surface shortwave absorptivity: 0.85
  2. Layers
    1. AC
      1. Input level: 3
      2. Asphalt material type: Asphalt concrete
      3. Layer thickness: Variable (table 36)
      4. Asphalt mix
        1. Cumulative percent retained on the 19.0-mm (0.75-inch) sieve: 0
        2. Cumulative percent retained on the 12.5-mm (0.375-inch) sieve: 5
        3. Cumulative percent retained on the 4.75-mm (#4) sieve: 30
        4. Percent passing the 0.075-mm (#200) sieve: 5
      5. Asphalt binder
        1. Conventional viscosity grade: AC 20
      6. Asphalt general
        1. Reference temperature: 21.1 °C (70 F°)
        2. Volumetric properties: As built
          1. Effective binder content (percent): 11.0
          2. Air voids (percent): 8.5
          3. Total unit weight: 2370 kg/m3 (148 lb/ft3)
        3. Poisson's ratio: 0.35
        4. Thermal properties
          1. Thermal conductivity of asphalt: 1.16 W/m-°C (0.67 BTU/h-ft °F)
          2. Heat capacity of asphalt: 0.27 W-h/kg-°C (0.23 BTU/lb-°F)

 

Table 36. Layer types and thicknesses for all sites.
Site Layer 1 (Surface) h1 (mm (inches)) Layer 2 (USCS)a h2 (mm (inches)) Layer 3 (USCS) a h3 (mm (inches)) Layer 4 (USCS)a h4 (mm (inches))
181028 AC 401 (15.8) CL 305 (12.0) CL 8 - -
261010 AC 58 (2.3) GW 279 (11.0) SW 508 (20.0) ML 8
282807 AC 267 (10.5) GW 762 (30.0) ML 8 - -
531007 AC 4.6 (1.8) GW 335 (13.2) MH 8 - -
536048 AC 152 (6.0) GW 86 (3.4) GW 254 (10.0) GW 8
091803 AC 178 (7.0) GW 254 (10.0) ML 8 - -
182008 AC 401 (15.8) ML 8 - - - -
182009 AC 450 (17.7) SW 610 (24.0) ML 8 - -
186012 AC 523 (20.6) GW   CL 8 - -
261004 AC 64 (2.5) GW 102 (4.0) ML 8 - -
261012 AC 152 (6.0) GW 114 (4.5) SW 8 - -
261013 AC 191 (7.5) GW 114 (4.5) SW 8 - -
271019 AC 122 (4.8) GW 152 (6.0) ML 8 - -
283081 AC 229 (9.0) GW 8 - - - -
283093 AC 305 (12.0) GW 8 - - - -

a Codes based on Unified Soil Classification System (USCS) standards.(19)

Structure: Unbound Base

  1. Unbound material: Variable (table 37)
  2. Thickness: Variable (table 36)
  3. Strength properties
    1. Input level: 3
    2. Poisson's ratio: 0.35
    3. Coefficient of lateral earth pressure: K=0.5
    4. Material property
      1. Modulus: Variable (table 37)
    5. Analysis type:
      1. Integrated Climatic Model (ICM) calculated modulus: ICM input
  4. Integrated Climate Model (ICM)
    1. Gradation and plasticity index: Computed by PDG
    2. Calculated/Derived parameters: Computed by PDG
    3. Soil characteristic curve fit parameters: Computed by PDG. Compacted, unbound materials

 

Table 37. Assumed layer moduli.
Layer Type (USCS)a Layer Description Modulus (megapascals (MPa) (kips per square inch (ksi))
GW Gravel 690 (100)
SW Sand 276 (40)
SM Silty Sand 138 (20)
CL Silty Clay 138 (20)
ML Clayey Silt 138 (20)
MH Silt 138 (20)

a Codes based on Unified Soil Classification System (USCS) standards. (19)

Climate

The climatic data for the detailed analysis sites were computed by the PDG as a function of the latitude/longitude of each site (table 38). Weather station data from the nearest three or four weather sites were used to estimate the site-specific weather data. The actual elevation of each site was used; however, all groundwater table elevations were set at 30.5 m (100 ft) to eliminate the resulting variations in pavement performance.

 

Table 38. Site locations used for interpolation of weather station data.
Site Longitude (decimal of degree) Latitude (decimal of degree) Elevation (m (ft))
094008 -72.558 41.798 47 (155)
181028 -87.016 38.196 134 (441)
185518 -86.853 40.477 20 (65)
261010 -83.656 43.179 241 (792)
274055 -94.074 45.424 299 (980)
275076 -92.975 45.034 300 (985)
282807 -89.655 34.356 90 (295)
284024 -91.041 33.359 300 (125)
501682 -73.241 44.326 122 (400)
531007 -119.602 46.048 275 (903)
536048 -122.138 47.788 37 (120)
091803 -72.0273 41.3949 50 (165)
094020 -72.5677 41.7020 61 (201)
095001 -72.4399 41.8485 163 (534)
182008 -85.0578 40.9456 242 (793)
182009 -86.0046 40.0308 239 (785)
185022 -86.0719 39.6278 255 (836)
186012 -87.4925 38.1673 144 (472)
261004 -88.6100 47.1000 300 (984)
261012 -83.5300 43.7100 315 (1032)
261013 -85.4918 43.4408 274 (900)
263069 -84.8745 43.8713 285 (935)
264015 -82.7996 42.9779 238 (780)
265363 -83.3915 42.1866 195 (640)
271019 -93.6021 45.5909 300 (980)
283081 -88.4405 34.2400 97 (317)
283093 -88.6736 30.4327 7 (24)
285006 -88.8100 34.3300 100 (329)
285805 -89.0600 30.4400 9 (30)
533813 -122.4600 45.5800 134 (440)
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