Modeling of Carbonation based on Thermo-Hygro Physics with Strong Coupling of Mass Transport and Equilibrium in Micro-pore Structure of Concrete

Ishida, Tetsuya; Li, Chun-He

doi:10.3151/jact.6.303

Cited by 41 publications

(10 citation statements)

References 13 publications

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“…The entire chemical process of concrete carbonation can be expressed in Eqn (1) (Papadakis, Vayenas, & Fardis, 1989;Zhou et al, 2015): At present, there are many models for calculating the carbonation depth of concrete, and the model can be categorised as theoretical model, semi-theoretical/semi-empirical model, and empirical model. The theoretical model (Papadakis et al, 1991a;Steffens, Dinkler, & Ahrens, 2002;Ishida & Li, 2008) is derived from physical principles. The parameters are well defined physical quantities and have clear meanings, but they are often difficult to be determined in practice.…”

Section: Concrete Carbonation Depth Modelmentioning

confidence: 99%

“…Throughout the past years, the concrete carbonation phenomenon has been widely researched (Papadakis, Vayenas, & Fardis, 1991a, 1991bIshida & Li, 2008;Ruan & Pan, 2012;Kari, Puttonen, & Skantz, 2014;Li, Dong, Bai, Lei, & Du, 2017a). However, very few researchers considered the influence of concrete stress on carbonation rate and carbonation depth.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Concrete Stress States on Carbonation Depth of Concrete

Wang

et al. 2019

Journal of Civil Engineering and Management

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Carbonation can lead to reduction of alkalinity of concrete and initiation of steel reinforcement corrosion. In durability design of concrete structures, the carbonation depth should be duly considered. However, the concrete stress state would influence the carbonation depth, and there has been inadequate research on such effect. In this study, it is proposed to introduce a stress influence coefficient to the concrete carbonation depth model. With reference to the experimental data from eleven research studies in the literature encompassing both tensile and compressive stress states, the relationship between stress influence coefficient and concrete stress ratio is quantitatively investigated, and mathematical equations relating the stress influence coefficient with the concrete stress ratio are established. Comparative study with three typical existing groups of equations shows that the proposed equations of stress influence coefficient are more reasonable and have a higher reliability. The effects of carbonation time, mix proportions of concrete on stress influence coefficient are also analysed, and the magnitudes of the effects are found to be approximately within ±10%. Finally, the modified carbonation depth models are proposed and verified by the experimental data, which suggests that the proposed models are of desirable accuracy. Adoption of the proposed equations as the modified formula of stress influence coefficient in the concrete carbonation depth model for practical applications is recommended.

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Section: Concrete Carbonation Depth Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of Concrete Stress States on Carbonation Depth of Concrete

Wang

et al. 2019

Journal of Civil Engineering and Management

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“…is the experimental constant, is the degradation effect coefficient for the performance of concrete chloride ion diffusion, is temperature, 0 is the chloride ion diffusion coefficient on temperature 0 , and 0 is the concrete hydration age for is the activated constant, which associated with water cement ratio [14]; when / = 0.4, is 6000 K, when / = 0.5, is 5450 K, and when / = 0.6, is 3850 K. The chlorine ion concentration in the location which has the distance from the surface can be calculated according to (4); thus, the corresponding number of chloride ions which moves at random in the horizontal direction can be arranged in the location of , by using the theory of diffusionlimited aggregation. When the chloride ions approach others, adsorption will occur and the combination of the chloride ion diffusion equations and the DLA algorithm is realized.…”

Section: Chloride Ion Erosion Based On the Dlamentioning

confidence: 99%

“…Assuming that the chloride ion concentration on the concrete surface is 3.0 Kg/m 3 , other parameters are the same as the previous section. The initial corrosion time is 9 years according to (4), and the destruction process of concrete structure is shown in Figure 3 as the DLA algorithm is used. The quantity formula of the reinforcement corrosion in the corrosion time is as follows:…”

Section: Reinforcement Corrosion Under Chloride Ion Erosionmentioning

confidence: 99%

“…According to the achievements from above levels, the theoretical methods on the concrete structure durability are mainly divided into three types. The first one is mathematical model method, which calculates the evolution of the material parameters directly using the chloride ion diffusion equation and carbonation equation [3,4]. The second method is numerical analysis, which derives the deterioration process of materials in time-space dimension by specified algorithms.…”

Section: Introductionmentioning

confidence: 99%

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Durability Evolution of RC Bridge under Coupling Action of Chloride Corrosion and Carbonization Based on DLA Model

Chen

2015

Mathematical Problems in Engineering

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Chloride attack and carbonization are the main factors which affect the durability of concrete structures, and the respective theoretical models are systematically established. However, the quantitative analysis and models about the coupling effect of chloride attack and carbonization are less, so the precision and level of durability analysis of reinforced concrete are restricted. Diffusion-limited aggregation (DLA) model can finely simulate the process of gas diffusion and condensation with randomness and fractal characteristics, which is suitable for revealing the durability evolution process of the chloride attack, carbonization, and the coupling action in concrete. Based on the principle of DLA, considering the factors such as diffusion depth, concrete properties, and exposure conditions which influence the characteristics of chloride diffusion and carbonization, as well as the coupling effect, an integrated DLA model is established. The concentration of carbon dioxide and chloride at any time and any location can be obtained and dynamically displayed based on the DLA model. The performance predict method for concrete and steel bars considering fatigue effect is presented based on DLA, according to the demand for bridge durability analysis. Numerical examples show that the method can dynamically and intensively simulate the durability evolution process of reinforced concrete bridge.

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