Fatigue performance of prefabricated coarse aggregate ultrahigh-performance concrete deck subjected to negative bending moment

The concrete deck of a steel-concrete composite bridge is vulnerable to cracking under negative bending mo-ments of fatigue loads. Thus, this work performed fatigue tests on the prefabricated decks to study the influences of the curing method and stress level on the fatigue behavior of the prefabricated ultrahigh-performance concrete (UHPC) deck in an assembled steel-UHPC composite beam under negative bending moments. A numerical simulation was further conducted to investigate the behavior of the decks with joints. The results indicate that the effect of the curing method on the fatigue performance of reinforced UHPC decks is not as pronounced as that on their static performance. The prefabricated UHPC decks exhibit excellent fatigue performance, and fatigue cracks do not form until 13 million loading cycles when the upper fatigue limit is near the breaking load. On the other hand, the deck with a joint has a substantially lower fatigue cracking resistance than the prefabricated ones. The maximum fatigue crack width of the deck with a joint is 0.08 mm at low stress amplitudes. As a result, even though the UHPC has high fatigue performance, further joint reinforcing is recommended.