Advantages of using ultra-high-performance concrete (UHPC) link slabs as an alternative to dowel bar joints in rigid road surfaces

The presented experimental study evaluates the possibility of replacing rigid pavement joints by a link slab made of ultra-high-performance concrete (UHPC) and shows advantages of it. Connection between the link slab and the pavement is provided by using shear studs. The tests focusing on evaluation of the load-deflection performance of UHPC link slabs was done using full-scale models. Twelve model structures containing UHPC link slabs were fabricated, tested and compared with specimens containing steel dowel bars. Parameters investigated in this study included link slab length and thickness, the number of shear studs, and joint width. The experimental results showed less deflection at the joint face, especially when the link slabs were 450 mm long and 70 mm thick, displaying a reduction in deflection by 47.46%-61.54% compared with steel dowel joint, at the load of 60 kN. Moreover the UHPC link slab ultimate load and relative deflection were more sensitive to changes in link slab thickness and length. Compared with model including shear stud connector, the ultimate load increased by 38.24%-88.52% and the relative deflection RD decreased by 56.12%-81.81% when the UHPC link slab was 450-mm-long and 70-mm-thick. Load transfer efficiency LTE of specimens with UHPC link slabs was slightly greater than that of specimens with dowel bars, which was in the range of 70%-90%. The values of LTE were more advantageous when two shear studs were used instead of one shear stud on each side. Mode of failure of specimens with UHPC link slabs consisted in shearing or flexural cracking near the joint region. The study indicated that UHPC link slabs could be a superior substitute for the traditional steel dowels in rigid pavements.