Abstract Most distresses in composite pavement structures, such as Portland cement concrete (PCC) overlays on PCC slabs-on-grade, form when their layers delaminate. To predict the delamination potential of bonded concrete overlays (BCOs) on slab-on-grade pavements at early ages, a mechanistic delamination model was developed in this study. To calibrate the model, an experimental BCO on jointed concrete pavement (JCP) section was constructed, and its behavior was monitored for the first 72 h after construction when subject to climatic loading, i.e. changes in temperature and moisture. Two- and three-dimensional finite element models of the BCO system were developed and calibrated. Theoretical equations to predict the corner stresses at the interface were formulated using the interfacial stresses predicted by the two-dimensional model as input. These equations yield stresses that match the results from the three-dimensional model well. A sensitivity analysis reveals the influence of overlay and JCP parameters, such as elastic modulus, slab length, thickness, and coefficient of thermal expansion, on the interfacial shear and normal stresses. This mechanistic delamination model has been incorporated into the HIPERBOND software developed for the Federal Highway Administration.