A NEW LOOK AT BONDED CONCRETE OVERLAYS FOR PAVEMENTS

The major benefits of bonded concrete overlays (BCO's) compared with either thicker un-bonded concrete overlays or thin bonded polymer overlays have long been recognized. However, the only successful applications of BCO's in practice have involved dedicated on-going research and experimentation in conjunction with favorable conditions and circumstances as in Texas, USA. It is shown that in more general situations pavement engineers should design for, and fully understand, no less than five important new concepts: Semi-rigid pavement model (see 2.2); Multiple cracking in both young and mature concrete (3.1); Thermal shunting (3.2); Fully developed early thermal crack width (3.3) and Dual cantilever concept for flexural resistance (3.4). Consistently successful BCO's in practice can only be expected if they are designed satisfactorily to all five new concepts as well as the familiar rigid pavement model. High grade concrete and good quality control and practice are also essential. The paper concludes with a BCO design example.