The function of steel reinforcement

The steel reinforcement in rigid pavements does not have the same function as any other concrete structure. In all structures apart from pavements, the tensile stresses that developed are much greater than those the concrete can sustain. Therefore, the reinforcement is placed to counteract the tensile stresses caused by applied external loads. 

In rigid pavements, the concrete slab is sited over the cement-bound layer and the tensile stresses that developed owing to traffic loading or ground reaction are very low. Even if they are high, they cannot cause sudden catastrophic failure of the pavement, as in other structures. The surface cracks may appear to affect the aesthetics and certainly accelerate pavement deterioration, but the structure will still be in use for a certain period (years). 

The functions of steel reinforcement in rigid pavements are primarily to counteract the temperature- and moisture-induced stresses, to reduce the number of transverse joints (jointed reinforced slabs) or eliminate the transverse joints (continuously reinforced slabs), to minimise future maintenance cost and, to a certain extent, to reduce the thickness of the slab. The reduction or elimination of transverse joints has a direct impact on the improvement of the riding quality offered. Some countries like the United Kingdom recommend to use, almost exclusively, continuously reinforced slabs on new constructions, hence the absence of transverse joints, with an thin (30 mm) or thick (100 mm) asphalt layer on top. 

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