Enhancing Shrinkage Properties and Bond Performance of Prefabricated Bridge Deck Connection Grouts: Material and Component Testing

Field-cast cementitious grouts are commonly used for connecting adjacent prefabricated bridge deck elements. These grouts can exhibit high shrinkage levels and are susceptible to premature bond failure at the interface between the precast concrete and connection grout. These actions commonly result in connection cracking, which can lead to serviceability issues in the bridge structure such as reinforcing bar corrosion, leakage, and degradation of structural performance. This study presents a set of potential strategies to enhance the shrinkage properties and bond performance of these grouted connections. The strategies include using advanced materials such as ultra-high performance concrete (UHPC), proper detailing of precast concrete connection surfaces, application of internal curing in connection grouts, and use of interface premoistening. The study includes experiments conducted at both material and component levels. At the material level, these potential improvement strategies were evaluated using standardized shrinkage and bond-strength test methods. To demonstrate the impact on structural performance, some of these strategies were used in a component-level investigation consisting of three large-scale bridge deck connection tests. Experimental results demonstrate that the suggested strategies can reduce shrinkage, enhance bond strength, and improve structural performance of connections.