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Probabilistic Analysis of the Durability of Piles with Microcracks Under Chloride Attack
Wei Shao,Danda Shi 한국콘크리트학회 2021 International Journal of Concrete Structures and M Vol.15 No.6
A probabilistic analysis approach for estimating the durability of piles with microcracks under chloride attack is presented. The chloride ingress model is obtained by considering the time-dependent diffusion process. The equivalent diffusion coefficient is derived to investigate the crack effect by introducing the crack effect factor. The fitting formula between the chloride diffusion coefficients and crack widths is established through experimental results, and the proposed equivalent diffusion coefficient is verified by comparison with the experimental results. The probabilistic evaluation of durability of piles with microcracks is performed, and then the parametric analysis is performed to study the effect of main parameters on the failure probability and durability life. The results indicate that the chloride concentration increases rapidly as the crack width increases at the same number of cracks. The durability life greatly reduces with increasing crack density of pile. The durability life predicted by probabilistic method is always less than those by deterministic method at the same condition. The deterministic approach may underestimate the threat of reinforcement corrosion induced by chloride attack, owing to the omission of probabilistic nature of main influencing parameters.
Numerical Simulation of Degradation Behavior of Concrete Piles in Sulfate Saline Soils
Wei Shao,Danda Shi 대한토목학회 2022 KSCE Journal of Civil Engineering Vol.26 No.1
In this study, an integrated numerical approach is developed to simulate the damage and degradation behaviors of concrete piles in sulfate saline soils. The governing equations for modeling the sulfate diffusion-reaction mechanism are presented. The diffusion properties of sulfate ions are modified by taking into account the effects of pore filling and expansion cracking on the diffusivity of sulfate ions. The model for simulating the volumetric expansion and damage evolution is presented. The developed numerical method is verified by comparison with experimental results of linear expansion. Numerical analysis results show that the sulfate concentration tends to increase with the exposure time at the same diffusion depth, but the growth rate gradually slows with increasing diffusion depth. The concentration of the reacted calcium aluminates increases gradually with the exposure time, while reduces with the increasing diffusion depth. The effective diffusion coefficient decreases sharply at the interface depth, and then increases gradually with an increase in diffusion depth at the same exposure time. The higher environmental sulfate concentration and water-cement ratio can accelerate the degradation of structural capacity of concrete piles.