Numerical Simulation of Degradation Behavior of Concrete Piles in Sulfate Saline Soils

Published on Oct 2, 2021in Ksce Journal of Civil Engineering1.805
路 DOI :10.1007/S12205-021-2225-9
Wei Shao (Shanghai Maritime University), Danda Shi (Shanghai Maritime University)
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Abstract
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.
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#1Dandan Sun (Tongji University)H-Index: 5
#2Kai Wu (Tongji University)H-Index: 16
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Abstract This study developed an integrated computational model to predict the time-dependent elastic deformation behaviour of concrete materials under external sulfate attack. The reactive-transport process of ions, pore size dependent diffusion coefficient and internal stress development induced by the ettringite formation inside the concrete pores are all considered in the model. Experiments of longitudinal expansion of specimens under different concentration of sulfate ions are carried out t...
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#1Mingbo Yao (Tongji University)H-Index: 1
#2Jingpei Li (Tongji University)H-Index: 14
Abstract An analytical method is proposed in this paper to present the effect of the degradation development of concrete friction piles subjected to vertical loads on the pile bearing capacity. This paper proposes an analytical solution of the sulfate diffusion-reaction equation based on Fick's law and Danckwerts' method in polar coordinates. A chemo-mechanics model is established to compute expansion based on the consideration of the pore filling. Furthermore, the effect of concrete expansion o...
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#1Dandan Sun (Tongji University)H-Index: 5
#2Kai Wu (Tongji University)H-Index: 16
Last. Lihai Zhang (University of Melbourne)H-Index: 30
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Abstract Long-term external sulfate attack can result in significant concrete degradation. The purpose of this study is to develop an experimentally validated reactive transport model to investigate the transport behaviour of sulfate ions in concrete containing interfacial transition zone (ITZ). The model takes into account the spatially dependent pore size in ITZ and the change of diffusion coefficient of sulfate ions due to the formation of ettringite and gypsum in concrete pores resulting fro...
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#1Yuguo Yu (UNSW: University of New South Wales)H-Index: 10
#2Yixia Zhang (UNSW: University of New South Wales)H-Index: 25
Abstract An integrated numerical method is developed to model the deterioration of mechanical properties of cement mortar under external sulfate attack (ESA). The proposed method is module-oriented, which includes three modules, i.e. an ionic diffusion module, a chemical reaction module and a mechanical module. In the mechanical module, an analytical model is developed for evaluating the variation of flexural strength under ESA. The development of internal pressure obtained from numerical comput...
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Abstract This paper numerically simulates time-dependent mechanical behaviors, such as stress redistribution and bearing capacity degradation, of concrete subjected to the coupled axial loading and sulfate attack. Based on Fick's law and chemical reaction kinetics, a diffusion-reaction model was proposed to obtain the spatial and time-dependent concentration distribution of sulfate ion, gypsum and ettringite. From previous study, a chemical damage, characterized by the volumetric expansion from ...
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#1Jingpei Li (Tongji University)H-Index: 14
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Abstract This study investigated the diffusion-reaction of sulfate in a cast-in-situ pile after different serving times. The diffusion equation was established based on Fick鈥檚 second law, and the model was established via the method of separation of variables by considering the appropriate initial and boundary conditions. An example of the diffusion-reaction of sulfate was compared to a traditional model. Additionally, the validity and advantages of the proposed method were verified. The results...
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#1Yuguo Yu (UNSW: University of New South Wales)H-Index: 10
#2Yixia Zhang (UNSW: University of New South Wales)H-Index: 25
Last. Amar Khennane (UNSW: University of New South Wales)H-Index: 18
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A finite element model is developed in this paper to simulate the degradation of cement-based materials when subjected to aggressive agents, including deionized water and sodium sulfate solutions. The proposed model includes three main modules, i.e. the ionic diffusion module, the chemical reaction module, and the damage quantification module. A modified Poisson鈥揘ernst鈥揚lanck model is developed to model the diffusion of multiple ions in the ionic diffusion module. The cracking suction effect is ...
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#2Sergio Henrique Pialarissi Cavalaro (UPC: Polytechnic University of Catalonia)H-Index: 26
Last. Antonio Aguado (UPC: Polytechnic University of Catalonia)H-Index: 40
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Abstract A diffusion鈥搑eaction numerical model is proposed to simulate the response of concrete exposed to external sulfate attack. Diffusion properties are modified based on the strain reached and the ratio of porosity filled by ettringite. A direct and intuitive approach is proposed for the consideration of the diffusion in a cracked porous media based on the constitutive law of the material. A methodology to compute expansions based on a more realistic consideration of the concrete porosimetry...
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#2R.E. Beddoe (TUM: Technische Universit盲t M眉nchen)H-Index: 10
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#1Chao Sun (NBU: Ningbo University)H-Index: 1
#2Jiankang Chen (NBU: Ningbo University)H-Index: 8
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Abstract Sulfate attack is one of the major durability problems in concrete structures. Sulfate ions present in concrete can react with cement hydration products to form gypsum and ettringite, and this may affect the pore structure and cause structural damage. In this paper, an experimental study was performed on the diffusion of sulfate ions in concrete. Based on the experimentally obtained results, a new diffusion model for sulfate ions was developed, taking into account the influence of the e...
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