Investigation of Pore Pressure in Bonded Concrete Overlays of Asphalt Pavement

Bonded concrete overlays of asphalt (BCOA) are used for pavement rehabilitation with extended service life. However, trapped moisture infiltrated from concrete joints can generate pore pressure at the concrete–asphalt interface and compromise interface bonding. This study aims to investigate the generation of traffic-induced pore pressure within the existing asphalt layer of BCOA pavements and evaluate the influences of various design parameters. A layered dynamic poroelastic model of BCOA pavement was developed to simulate a fully saturated asphalt layer, considering different permeable conditions at the interfaces. The results indicate that the maximum pore pressure occurs at the portland cement concrete (PCC)–asphalt interface as the tire loading moves over the joint, and hydraulic conductivity of the saturated layer affects pore pressure most. Depending on the deterioration condition of the existing asphalt layer, higher pore pressure is generated when it has a lower resilient modulus or greater thickness. In contrast, the thickness and elastic modulus of the PCC slab show limited effects on pore pressure development. Additionally, pore pressure becomes more pronounced when the upper portion of the existing asphalt layer is more deteriorated and becomes saturated, while the lower portion remains intact and dry.