ABSTRACT
The main problem of fatigue cracks on orthotropic steel deck (OSD) is the reduction of local stiffness that harms bridge serviceability, which may lead to pavement damages, lower driving comfort, and even corrosion on the top of the deck. Hence, measures to extend the fatigue life should be implemented to address these issues. This paper proposes to use a semi-rigid pavement made by methyl methacrylate (MMA) mortar on OSDs with existing fatigue cracks. The fatigue test is designed for a three-phase process: I) Pre-damage phase in which fatigue loading is applied on OSD specimens; II) Fatigue life extension phase in which fatigue loading is applied on the damaged OSD specimens with added semi-rigid pavement layers; III) Extra phase in which fatigue loading is increased to achieve the eventual failure of specimens. As a result, the specimens are always failed due to the penetrating crack at the rib-to-deck weld root. The crack is initiated in Phase I, then grows to penetrate through the deck plate first, and the semi-rigid pavement layer in the following phases. It can be addressed that the performance of the interface between MMA mortar and OSD is kept in a good shape, so that the semi-rigid pavement layer can not only help the prevention of crack growth, but also provide sufficient carrying capacity by forming a composite structure combined with the OSD.
