Fatigue cracking in bridge deck and damage with asphalt pavement are severe issues to orthotropic steel bridge plates. In terms of the concept of the amelioration of the stress condition of the pavement, an innovative composite bridge deck system composed of orthotropic steel decks and a Reactive Powder Concrete (RPC) layer was proposed. The longitudinal partition test and lateral bending tests clearly illustrate that the bending tensile strength of this composite deck structure considerably exceeds the design stress, and its weight is approximately equal to those of the traditional pavement. Furthermore, the results of lateral bending tests adequately demonstrate that the bending strength of this new system is dependent on the reinforcement ratio and the effective height of the section. As the reinforcement ratio is doubled and tripled,the bending strength is enhanced by 15 and 40 percent respectively. Similarly, the bending tensile strength increases by 30 to 50 percent on various reinforcement ratios when the effective sectional height is climbed by 20 percent. Consequently, the risk of crack or damage during bridge operation period will shrink substantially as the improvement of reinforcement ratios and the effective height of the section.