Interlock mechanism of concrete block pavements

The structural mechanics of interlock that causes the surface to adopt a mode of behavior similar to the conventional flexible pavements is one of the unique characteristics of the behavior of concrete block pavements. A way in which pavers dissipate stresses applied by rolling loads has been investigated at the University of Newcastle (U.K.) from 1996 to 2000 and an understanding of the interlock process thereby developed. This paper explains the theoretical details of the interlock mechanism for vertical and rotational interlock excluding horizontal interlock and it demonstrates how it can be used to establish the nature and value of interlock. It shows how surface loading produces patterns of stress within the bedding sand as patch loading rolls across pavers. Their resolution of the structural mechanics clarifies many hitherto unexplained bedding material failures by examining the way in which the local vertical stress transients develop and travel through bedding materials. The performances of pavers having different geometries are also compared in terms of the bedding material stress distribution underpinning the interlock mechanism.