Where conventional concrete pavements are concerned, there are three subtypes of pavement, which vary in terms of steel reinforcement requirements.
Jointed Plain Concrete Pavement (JPCP)
Jointed Plain Concrete Pavements are the most common conventional concrete pavement. For JPCP, concrete slabs are constructed directly over a prepared aggregate base structure. Transverse joints separate the concrete into panel sections, and are located where the concrete would be expected to crack naturally (typical panels are 4 – 6 meters wide, with a maximum width to length ratio of 1.5:1). Transverse joints are installed perpendicular to traffic, and allow load transfer between the panels according to two different methods, as determined by pavement thickness:
- Undoweled: Typically, for pavements 175 mm thick or less, joints do not require dowel bars, and load transfer is achieved through aggregate interlock.
- Doweled: For pavements 200 mm thick or greater, smooth steel dowel bars are placed at the mid-point of the pavement thickness parallel to the direction of traffic. Tie bars (deformed rebar) hold the pavement lanes together, placed perpendicular to traffic direction along the longitudinal joint.
Continuously Reinforced Concrete Pavement (CRCP)
Typically used for heavy duty applications, such as bus lanes and bus stops. CRCP does not require construction joints, and instead utilizes reinforcement steel (approximately 0.6-0.7% by cross-sectional area) to hold the expected transverse cracks tightly together. Quebec utilizes CRCP in the Montreal area due to the congested highway system and need to have a pavement that has very minimal rehabilitation requirements.
Jointed Reinforced Concrete Pavement (JRCP)
Older JRCP concrete pavement designs utilized a layer of thick wire mesh located in the top third of the concrete panels. Dowel bars were also placed along the transverse joints which were spaced 25 to 27 m apart compared to 4 to 6 m for JPCP. NOTE: This type of concrete pavement design is no longer recommended for new construction.