The objectives of this research were to experimentally study the influence of surface preparation on bond strength between concrete overlay and underlay in pre-stressed slab bridges and to explore the best practice for placing concrete overlay based on experimental results. Different surface preparation conditions were investigated while other parameters such as water-to-cement ratio, fine and coarse aggregates, cement and curing conditions were kept constant in order to study the influence of surface preparation on bond strength between the concrete overlay and underlay. The main focus of this research was on studying the effect of changing surface pattern consisting of different groove depth, spacing and the effect of using slurry mix made of overlay ingredients at the bond interface. The results also show that surface preparation without adequate groove pattern provides lower bond strength than the cases in which the groove patterns are implemented.