Steel-Free Composite Slabs Made of Reactive Powder Materials and Fiber-Reinforced Concrete

In this article, the authors propose a design for deck slabs of slab-on-girder bridges. The design combines two established approaches: the Canadian steel-free fiber-reinforced concrete (FRC) slab, and high-performance reactive powder composite materials (RPCM), to solve the problem of deterioration of concrete slabs due to the corrosion of embedded reinforcement. In this design, nonreinforced precast panels made of RPCM and restrained by external steel straps serve as permanent formwork for cast-in-place FRC. The two materials are made composite through an easy surface preparation, which gives a texture similar to that of an imprint of air-cell wrapping sheets, and through shear studs of the straps and of the supporting girders. Slant shear tests on composite RPCM and FRC cylinders showed that the suggested surface texture is relatively rough. Half-scale tests on the proposed composite slabs proved that the precast RPCM and the cast-in-place FRC behave compositely up to failure. The authors conclude that the new design was able to prevent the longitudinal cracking, which is the main drawback of the FRC-only steel-free slab system. In addition, because reinforcement laying and propping are unnecessary in this design, construction costs are reduced.