Lattice modelling of fracture in composite concrete pavements and overlays

Recent research in the USA has focused on the design, construction and performance of composite concrete pavements-that is, two heterogeneous concrete layers placed sequentially using wet-on-wet techniques. In addition, other research into rehabilitation practices has focused on improving the design and analysis of bonded concrete overlays of concrete pavements and bridge decks. While these techniques can offer many benefits to pavements and bridges, they also introduce some uncertainties, including the possibility of thermally, hygrally, or mechanically induced fracture and separation at the interface of the concrete layers. In this work, the potential for mixed-mode fracture at the interface between concrete layers is evaluated using three-dimensional lattice models. This discrete approach is coupled with a finite element model for plate behaviour away from the potential cracking zone. The model, using two damage criteria, was verified and validated against experimental data for failure in notched concrete beams in three-point testing. In addition, simulations were conducted using each criterion for interface failure in a composite concrete pavement. The simulation results suggest that interface fracture is unlikely, even when considering unfavourable conditions such as substandard material properties and large temperature differences between the pavement layers.