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)

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)

^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

^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.