Fatigue performance of steel–concrete composite slabs with a cementitious adhesive subjected to water leakage

•Fatigue behavior of composite slabs with water leakage is examined.•The effect of water leakage is significant on decreasing the fatigue life of the composite slabs.•Water weakens the bond of the cementitious adhesive when associated with fatigue loading. A steel–concrete composite slab using a cementitious adhesive has been developed to simplify the design of shear connectors between concrete and a steel bottom plate. Fatigue is one of the critical issues for constructed bridge decks, so a moving-wheel fatigue test was performed using the composite slab in a previous study. The test showed the superior fatigue behavior of the proposed composite slab system, while the needs for follow-up research emerged because existing bridge deck slabs frequently suffer from water leakage. The study deals with testing thirteen composite slabs having the cementitious adhesive subjected to water leakage in static and cyclic loadings. Test results show that the fatigue life of the composite slabs in water leakage is significantly lower than that of the slab tested in a dry condition. To further understand the effect of water on reducing the efficacy of the adhesive, supplementary tests are conducted with an emphasis on water-absorption and shear capacity in a wet environment.