Why reinforcement in road pavement?

Jointed reinforced concrete pavement (JRCP, see Figure 1) uses contraction joints and reinforcing steel to control cracking. Transverse joint spacing is longer than that for JPCP and typically ranges from about 7.6 m (25 ft.) to 15.2 m (50 ft.). Temperature and moisture stresses are expected to cause cracking between joints, hence reinforcing steel or a steel mesh is used to hold these cracks tightly together. Dowel bars are typically used at transverse joints to assist in load transfer while the reinforcing steel/wire mesh assists in load transfer across cracks.

Properties

Crack Control

Contraction joints as well as reinforcing steel.

Joint Spacing

Longer than JPCP and up to a maximum of about 15 m (50 ft.). Due to the nature of concrete, the longer slabs associated with JRCP will crack.

Reinforcing Steel

A minimal amount is included mid-slab to hold cracks tightly together. This can be in the form of deformed reinforcing bars or a thick wire mesh.

Load Transfer

Dowel bars and reinforcing steel. Dowel bars assist in load transfer across transverse joints while reinforcing steel assists in load transfer across mid-panel cracks.

Other Info

During construction of the interstate system, most agencies in the Eastern and Midwestern U.S. built JRCP. Today only a handful of agencies employ this design (ACPA, 2001[1]).

In general, JRCP has fallen out of favor because of inferior performance when compared to JPCP and CRCP.

Source: http://www.pavementinteractive.org/article/jointed-reinforced-concrete-pavement