Design, Preparation, and Performance of a Gradient Structural Concrete Member

The design of a gradient structural concrete component was investigated to improve the durability of concrete structures under harsh environments. On the basis of the theory of functionally graded materials with high crack resistance, low transmission, and good self-repairing capability of the cement-based material without a mesoscopic interface transition zone, the reinforcement on performance of protective layer could be achieved. Given the differences in construction situation, structural shape, inner, and outer layer among materials, the gradient structural concrete member (GSCM) and general single-layer concrete member would be prepared. The Deformation coordination capacity, chloride transport properties, and preparation method were investigated, through simulation of stress and deformation, interface bond strength test, and accelerated corrosion test. Results showed that the consistent volume deformation of GSCM did not cause failure, and the surface layer strength of GSCM improved by up to 30%. Only 0.02–0.05 mm cracks were observed without the aid of instruments, and 0.2–0.5 mm cracks were observed in general single-layer members. Moreover, the GSCM had a depth of penetration and chloride diffusion coefficient of 0 mm and $6.3\times {10}^{-13}{\mathrm{m}}^2/\mathrm{s}$ , respectively. These values indicated that the GSCM exhibited good tricyclic assemble performance and satisfied the construction requirement. Meanwhile, the values obtained for the general single components were 15 mm and $12.8\times {10}^{-13}{\mathrm{m}}^2/\mathrm{s}$ .