Characterization of the Mode I Interface Fracture within Bimaterial Permeable Pavement Systems

Permeable removable urban pavement (RUP) is an innovative pavement system consisting of bimaterial permeable/plain concrete slabs, developed to mitigate climate change–related impacts. While the durability of bimaterial pavements is linked to the interface bonding performance, accurate characterization of the interface fracture between their different layers is essential. This study investigates the feasibility of the wedge splitting test (WST) for Mode I fracture characterization of permeable/plain concrete interface. Given the high contrast in the elastic moduli (Epermeable/Eplain=0.5), digital image correlation (DIC) shows that Mode I (opening) displacements are significantly higher than Mode II (shear) displacements. This confirms that the WST tests conducted in this research can be considered as Mode I dominant tests for the interfaces between materials with contrasting moduli. Additionally, the obtained fracture results highlight the importance of monitoring the opposite specimen faces for accurate fracture characterization. Thereafter, two specimen preparation methods, Fresh/Fresh and Fresh/nonFresh, are discussed. The results indicate that the Fresh/nonFresh interface tends to have a more ductile bond with a higher specific fracture energy.