Experimental characterization of prefabricated link slabs with randomly oriented and oriented-fibres UHPC under multiple geometric configurations

The link slabs are structural elements connecting two bridge decks, ensuring structural continuity without altering the simple support scheme of the deck. These elements provide the durability benefits of integral bridges by eliminating expansion joints between beams, which are prone to water infiltration and exposure to degrading agents. The development of link slabs is closely connected to the progress in composite materials. Ultra-High Performance Concrete (UHPC) is a cementitious material capable of ensuring the mechanical performance of link slabs under operational loads, thanks to high resistance and durability. This work presents an extensive experimental characterization of prefabricated link slabs, considering an experimental setup representative of operational conditions. The authors examined nine experimental configurations, varying both the geometry and the material. For geometry, they varied the bolts’ edge distance and the thickness of the unbonded layer. For material, they studied link slabs made of Reinforced Concrete (RC), UHPC with randomly oriented fibres, and UHPC with oriented fibres. The effect of the volumetric fraction of fibres was assessed in the slabs with oriented fibres. The results provide practical recommendations for selecting the combination of geometric properties and materials to maximize the mechanical performance of prefabricated UHPC link slabs.