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A high-cycle fatigue constitutive model for concrete joint interfaces is proposed and the direct path-integral scheme for RC-PC structures with junction planes is presented. Both cyclic pullout and the associated dowel action of reinforcing bars are formulated at a crack/joint section in terms of the relative displacement derivatives of a pair of joint planes. The proposed differential formula is verified by high cycle fatigue experiments of dowel bars and pullout of reinforcement crossing a joint in structural concrete. In conducting the direct path integral of the constitutive equations, a logarithmic time integration method is adopted so as to achieve highly accelerated computation with reasonable accuracy. The scheme is applied to the assembly of pre-cast pre-stressed concrete members with reinforced concrete joints for the purpose of life-cycle assessment. A mechanics-based discussion is presented of the different fatigue life observed in precast slabs with localized discrete joints and in monolithically constructed reinforced concrete, where dispersed cracking develops.

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This study develops an analysis method for estimating the process of corrosion in concrete, including initial corrosion and the onset of corrosion-induced cracking. The method is suitable for application in rationalizing the verification of the durability of salt-damaged RC structures. Corrosion deterioration is computed by coupling the analysis of structure with the analysis of reinforcement corrosion. A method of calculating macro-cell corrosion in consideration of macro-cell corrosion current density is also proposed, focusing on cathodic elements of a reinforcing bar. The proposed analytical method is validated against dry-wet cyclic tests with salt solution to simulate macro-cell corrosion. We verify the accuracy of the method by confirming the non-uniformity of the concrete before cracking and, by coupling the analysis with structural analysis, investigating how the expansion ratio of corrosion products and diffusion coefficient of chloride ions affect the onset of corrosion, the time of initial corrosion cracking, the chloride ion density and the corrosion amount. This paper is based on an original paper (Suzuki et al. 2014) written in Japanese.

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