Introduction

Dowel bars are placed at the transverse joints of concrete pavement and they take part in partial wheel load transfer from one slab to its adjacent slab. The dowel bars also allow axial thermal expansion and contraction of the concrete slab along the axis of the dowel.

The bars are generally made up of mild-steel-round-bars of short length. Around half of the length of this bar is embedded in one of the concrete slabs and the remaining portion is bonded in the other adjacent slab. One end of the bar is kept free for the movement during expansion and contraction of the slab due to change in temperature.

The performance of the dowel bar system drastically falls when voids are created between the dowel bars and the concrete slab (Porter 2001). Such a situation develops stress concentration and failure may take place rapidly. The void space may get filled with water and corrosion action to the dowel bars may get aggravated. Subsequently, the load transfer mechanism tends to fail and the differential settlement of the concrete slab may occur (Porter 2001). Differential settlement may further cause breakage of slabs due to impact loading of the vehicles. Thus, the design adequacy of dowel bar system and proper placement to the concrete pavement slab is an important consideration.