Experimental investigation of cracking behaviors of ultra-high performance concrete link slabs subjected to negative moments

The excellent mechanical properties and durability of ultra-high performance concrete (UHPC) render it a promising material for use in link slabs subjected to negative moments. However, the scarce investigation on its cracking behaviors poses a significant challenge to a reasonable design. Six link slabs of different materials, thicknesses, and lengths are prepared and tested. The cracking characteristics of the link slabs are quantitatively analyzed. Then, the applicability of crack width calculation methods outlined in existing standards to UHPC link slabs is evaluated. Finally, a parametric analysis is performed to develop feasible crack width control strategies. The results demonstrate that the application of UHPC in link slabs and the increases in slab thickness and length contribute to delaying crack initiation and propagation, with the maximum improvement in cracking load and common environment load-carrying capacity being 400% and 433%, respectively. The French standard provides a reliable method for predicting crack widths in UHPC link slabs. Increasing the tensile strength of UHPC and reducing the diameter of the reinforcement and cover thickness are practical methods to reduce the crack width in link slabs. The research contributes to a comprehensive understanding of the cracking behaviors and proper design of UHPC link slabs.