In this study, mechanical behavior and failure pattern of composite concrete deck were investigated. A unique dimension of steel concrete deck was fabricated and tested in four-point bending. Two series of decking were also designated with bolts at a spacing of 15 cm and 30 cm, used to compare with those without bolt. Totally, 9 composite concrete decks were tested in a close-loop servo-hydraulic testing system (MTS) using displacement control. Load versus displacement curves as well as failure patterns of the specimens were studied to figure out the mechanical behavior of this type of composite structure.