Experimental study on flexural and interfacial shear properties of the steel-UHPC glued composite deck

This paper proposes a Steel-UHPC Glued Composite Deck (SUGCD) to mitigate the fatigue cracking of orthotropic steel deck and improve the destructible paving layer of bridge, respectively. A series of flexural tests are con-ducted on 20 SUGCDs and shear tests are performed on 20 push-out specimens, respectively. The objective is to examine the effects of various interface treatment methods, reinforcement ratios, and types of epoxy adhesive on the flexural and shear properties of the composite decks. Additionally, the characteristic strength of the UHPC layer is calculated by the section conversion method. The results demonstrate that the elastic phase of SUGCD under hogging moment depends on the material properties of UHPC and the interface properties of the composite deck, respectively. The maximum difference of the cracking load of UHPC layer is 150.2% for various interface treatment methods. The composite deck has a higher elastic limit and cracking load under sagging moment than the hogging moment. The interface remains intact when the composite deck reaches its yielding strength, indicating that the interface has sufficient bonding strength. Finally, the cast-in-situ push-out specimens exhibit the optimal interfacial performance with ZR14 epoxy adhesive and 3-5 mm bauxites, and the prefabricated push-out specimens with ZR14 epoxy adhesive demonstrate the best interfacial performance, respectively. Therefore, the proposed steel-UHPC glued composite decks may meet the requirement in practical engineering.