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PAVEMENTS

PAVEMENTS. Pavement Types and Materials. Pavement Purpose. Load support Smoothness Drainage. DC to Richmond Road in 1919 – from the Asphalt Institute. Pavement Condition. Pavement Condition. Pavement Condition. Pavement Types. Rigid Pavements. Flexible Pavements. (WSDOT, u.d.).

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PAVEMENTS

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  1. PAVEMENTS Pavement Types and Materials

  2. Pavement Purpose • Load support • Smoothness • Drainage DC to Richmond Road in 1919 – from the Asphalt Institute

  3. Pavement Condition

  4. Pavement Condition

  5. Pavement Condition

  6. Pavement Types Rigid Pavements Flexible Pavements (WSDOT, u.d.) Composite Pavements

  7. Flexible Pavement • Structure • Surface course • Base course • Subbase course • Subgrade

  8. Higher AV (%) Higher Permeability Higher Macrotexture Asphalt Concrete Mix Components Aggregates Air Void Asphalt Binder Gap Graded Mixes Dense Graded Mixes Open Graded Mixes

  9. Types of Flexible Pavement Dense-graded Open-graded Gap-graded

  10. Flexible Pavement – Construction

  11. Adjusts to limited differential settlement Easily repaired Additional thickness added any time Non-skid properties do not deteriorate Quieter and smoother Tolerates a greater range of temperatures Loses some flexibility and cohesion with time Needs resurfacing sooner than PC concrete Not normally chosen where water is expected Flexible Pavements Advantages Disadvantages

  12. Dynamic Modulus, E* Stiffness property Function of Temperature rate of loading Age binder stiffness aggregate gradation binder content air voids Inputs Asphalt mixture properties Asphalt binder Air voids Asphalt Mix

  13. Rigid Pavement • Structure • Surface course • Base course • Subbase course • Subgrade

  14. Good durability Long service life Withstand repeated flooding and subsurface water without deterioration May lose non-skid surface with time Needs even sub-grade with uniform settling May fault at transverse joints Rigid Pavements Advantages Disadvantages

  15. Types of Rigid Pavement • Jointed Plain Concrete Pavement (JPCP) • Jointed Reinforced Concrete Pavement (JRCP)

  16. Types of Rigid Pavement • Continuously Reinforced Concrete Pavement (CRCP)

  17. Rigid Pavement – Construction Slipform Fixed form

  18. Rigid Pavement Terms • S’c (PCC modulus of rupture) • A measure of PCC flexural strength • Usually between 600 and 850 psi • J (load transfer coefficient) • Accounts for load transfer efficiency • Lower J-factors = better load transfer • Between 3.8 (undoweled JPCP) and 2.3 (CRCP with tied shoulders) • Ec (PCC elastic modulus) • 4,000,000 psi is a good estimate • k (modulus of subgrade reaction) • Estimates the support of the PCC slab by the underlying layers • Usually between 50 and 1000 psi/inch

  19. Pavement Structure • Bedrock • Presence within 10 feet of the pavement surface influences the structural response of the pavement layers • Inputs • Layer thickness (infinite) • Unit weight • Poisson’s ratio • Layer modulus

  20. Subgrade • Characterized by strength and/or stiffness • California Bearing Ratio (CBR) • Measures shearing resistance • Units: percent • Typical values: 0 to 20 • Resilient Modulus (MR) • Measures stress-strain relationship • Units: psi or MPa • Typical values: 3,000 to 40,000 psi

  21. Subgrade Some Typical Values

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