SESSION 2

Concrete Pavement Type Selection and Design Features

Objectives

   Identify concrete pavement types Recognize considerations in type selection List concrete pavement design features and recognize their beneficial effects

Concrete Pavement Types

 Jointed plain concrete pavements (JPCP)  Jointed reinforced concrete pavements (JRCP)  Continuously reinforced concrete pavements (CRCP)

JPCP

3.7 to 6.1 m (typ.) (12 to 20 ft) 3.7 to 6.1 m (typ.) (12 to 20 ft)

PLAN VIEW

Transverse Joints (with or without dowels) Longitudinal Joint (with tiebars)

JPCP

JRCP

7.6 to 18.3 m (typ) (25 to 60 ft)

PLAN VIEW

Welded Wire Fabric Reinforcing Transverse Joints (with dowels) Longitudinal Joint (with tiebars)

JRCP

CRCP PLAN VIEW

Continuous Longitudinal Reinforcement (Deformed Bars) Typical Crack Spacing (0.9 to 2.4 m) (3 to 8 ft) Longitudinal Joint (with tiebars)

CRCP

Pavement Type Factoids

 JPCP is the most common concrete pavement constructed today  JRCP was widely constructed in 1960s and 1970s  CRCP is constructed by a few agencies, often on high-volume, urban roadways

Considerations in Selection

         Traffic levels Subgrade Climate Initial construction and life-cycle costs Service life Future maintenance/rehabilitation Reliability Contractor experience Local experience/past performance

Pavement Characteristics Pavement Type JPCP Advantages

  Reliable design Applicable in all locations

JRCP CRCP

  Fewer joints Less concern about random cracking     No transverse joints Smooth riding Long service life Low maintenance

Disadvantages

  Increased joint cost Increased joint maintenance   Joint deterioration Crack deterioration   High initial cost Rehab is difficult

NCHRP 1-32 Pavement Type Selection Guidelines >6.0

3.0-6.0

Undoweled or Doweled JPCP Doweled JRCP CRCP 1.5 3.0

Undoweled or Doweled JPCP Doweled JRCP Doweled JPCP Doweled JRCP CRCP 1.5

Undoweled JPCP 0 5 10 15 20 ESALs, millions

Design Features

  Design elements contributing to performance Key design features (European researchers) – Nonerodible base course – Positive drainage – Strengthened structure (thick slab, doweled joints, or CRCP) – Slab stress relieving features (widened slabs, trapezoidal cross section)

Relative Effect of Design Features on JPCP Performance

        Initial smoothness Load transfer Subdrainage Base type Slab widening Joint spacing Slab thickness Slab modulus/strength

Increasing Effect on Performance

Summary

   Concrete pavement types Considerations and selection Design features