Full-Scale Experimental Verification of UHPC-RC Composite Slab Culvert with a Clear Span of 8 m

Abstract

To enhance the structural performance and durability of a conventional reinforced concrete (RC) cover slab over a culvert as well as to improve its spanning ability, this paper presents a novel ultrahigh-performance concrete (UHPC)-RC composite cover slab with a clear span of 8 m. The inverted prefabricated UHPC single-Tee or double-Tee beam was placed at the bottom of the cast-in-place normal strength concrete to form the UHPC-RC composite cover slab. A full-scale experimental test on the UHPC-RC composite cover slab was conducted to explore and quantify its mechanical performance. The structural characteristics of the slab, such as failure mode, moment capacity, flexural stiffness, concrete strain distribution, and cracking behavior, were experimentally investigated. The results indicated that, compared to the conventional RC cover slab, the UHPC-RC composite cover slab exhibits a typical flexural failure with a higher cracking resistance, flexural stiffness, flexural capacity, and ability to restrain the propagation of the cracks. An optimized scheme is successfully applied to the practical project. Field testing during the construction process was conducted to investigate the flexural performance of the new composite structure. The results indicated that the structural behavior of the UHPC-RC cover slab aligned well with its predicted values, demonstrating the effectiveness and feasibility of using the UHPC-RC composite cover slab in practical engineering applications.