Lattice models of debonding in composite concrete pavements

Recent research in the United States 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. These techniques introduce some uncertainties over conventional single-layer paving, 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 is assessed using three-dimensional lattice models. This discrete approach is coupled with a finite element model for plate behavior 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 in the presence of extreme thermal gradients over the pavement depth.