In order to re-decking RC deck to precast PC concrete deck, thin mortar layer is settled among deck and steel girder. It is considered that relative slip behavior, shear strength, composite action and failure mechanism of composite structure consisted by thin mortar layer is not same as without that configuration. Therefore push-out test for RC and PCaPC deck considering haunch and thin layer mortar is conducted. From the results, it is found that; cracks of thin mortar layer of PCaPC deck specimens lead deterioration of the shear resistance; thin mortar layer of PCaPC deck will results in action of shear and bending moment to the studs, which induces the deterioration of maximum resistance strength compared to RC deck.
