An experimental study on hybrid fibre reinforced engineered cementitious composite link slabs under static and fatigue loadings

This study conducted experimental investigations on the structural performances of link slabs which are con-structed by using a newly developed hybrid-fibre reinforced engineered cementitious composite (hybrid-ECC). Both static and fatigue loadings were applied to validate the feasibility, provide a proof of concept study and demonstrate the benefits using hybrid-ECC for bridge link slabs application. Three identical quarter-scaled hybrid-ECC link slabs, simulating a link slab used for a typical 35-meter multi-span simply supported bridge, were fabricated. These slabs, denoted as LS-1, LS-2 and LS-3, were tested under designated static and fatigue loadings. Slab LS-1 was tested under static loading to obtain the flexural strength of the slab. Slabs LS-2 and LS-3 were tested under fatigue loadings to evaluate their fatigue performances under normal service loading and overload scenarios, respectively. Structural performances of these slabs in terms of deformation and crack width control capability, strain development on reinforcement bars and estimated service life were evaluated. It was observed that multiple microcracks were developed under both static and fatigue loadings. Slab LS-2 survived ten million cycles of service fatigue loading while LS-3 survived two million cycles of overload fatigue loading. For all the tests conducted under static and fatigue loadings, the maximum crack width observed on the three link slab samples was all controlled within the allowable limit of 0.2 mm until failure occurred. Based on the test results, it was estimated that if only the effects due to normal traffic loading and temperature variation were considered, the hybrid-ECC link slab could achieve a service life of more than 40 years. Therefore, the experi-mental study reconfirmed that the hybrid-ECC showed a high potential to improve the fatigue performance and extend the service life of link slab in bridge construction.