In order to expand the life-time as well as to eliminate some drawbacks associated with the use of traditional normal strength concrete in bridge construction, a new composite NSC/ SHCC deck slab is proposed and investigated. The superior tensile characteristics of the Strain Hardening Cementitious Composites (SHCC) could be engineered when a thin layer of such material is used in the tension side of the deck slab. The effects of reinforcement ratio of the main steel as well as the thickness of the substrate SHCC layer have been studied. Five composite NSC/SHCC slab specimens along with two control specimens made of normal strength and high-performance concrete were prepared and tested. The responses of all specimens have been compared from the viewpoint of ultimate capacity, developed ductility and cracking characteristics. The experimental results showed that the proposed NSC-SHCC deck system was found to have enhanced performance with regard to flexural capacity and serviceability, compared to the conventional reinforced concrete deck. The increase of the SHCC thickness had little effect on the cracking, yielding, and ultimate loads, while a considerable enhancement in the post-cracking behaviour was obtained with the increase of reinforcement ratio.