Experimental Study on Tensile Behavior of Wet Joints in a Prefabricated Composite Deck System Composed of Orthotropic Steel Deck and Ultrathin Reactive-Powder Concrete Layer

Abstract

The widely used orthotropic steel deck system is subject to several durability problems: fatigue cracking of the steel, wearing of the surfacing, and corrosion. Thus, the composite deck system composed of an orthotropic steel deck and an ultrathin reactive-powder concrete (RPC) layer was proposed. In a prefabricated composite deck system, joints formed between the prefabricated RPC layer and the cast-in-situ RPC layer are defined as wet joints. The experimental study was conducted on the tensile behavior of RPC wet joints to ensure the integrity of the prefabricated deck system and the serviceability and durability of the RPC layer. Two series of tests were conducted, including seven tensile tests on panels and four negative bending tests on beams. In these tests, five types of new wet joint details were designed in addition to the integral casting detail and the conventional wet joint with a vertical, plane interface. To study the mechanical properties and crack resistance performance of different wet joint details, the load-deformation curves and the nominal RPC tensile stress–maximum crack width curves of the models in each test series were compared. Comparisons showed that the mechanical properties of different wet joint details were close to one another. However, their crack resistance performance differed considerably. The sawtooth wet joint, rectangular wet joint, and steel plate–enhanced wet joint had substantially better crack resistance performance than the conventional wet joint. In contrast, the inclined wet joint and the reinforcement-enhanced wet joint had poor crack resistance performance because of their plane interfaces. Additionally, test results suggested that the postcracking behavior of the RPC layer was improved by the steel fibers. Therefore, for more economical bridge designs, the durability-based allowable RPC tensile stress was recommended instead of the initial cracking stress.