Simplified methodology to evaluate the external sulfate attack in concrete structures

Ikumi, Tai; Cavalaro, Sérgio Henrique Pialarissi; Segura, Ignacio; Fuente, Albert de la; Aguado, Antonio

doi:10.1016/j.matdes.2015.10.084

Cited by 58 publications

(21 citation statements)

References 29 publications

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“…After each representative point in the representative point set is substituted into the SKE-SCR, equation (25) becomes a set of deterministic ordinary differential equations which can be conveniently solved by the fourth-order Runge-Kutta method. Figure 6 presents some samples of the concentration evolution process of calcium hydroxide, ettringite, and gypsum, where the black solid line represents the results calculated from the DRE-SCR; points 2132, 4311, 6657, and 7489 are some points randomly specified from the representative point sets.…”

Section: Results Analysis Of the Ske-scrmentioning

confidence: 99%

“…erefore, the reaction rate υ j (X(t), τ) of reaction R j will be a random process according to the stochastic process theory, where τ is the time interval of two time points t 2 and t 1 . As proposed in the literature [25], generally, the random process υ j (X(t), τ) can be regarded as a Gaussian random process with the mean vector υ j (X(t)) and covariance function D j . us, in the time interval τ, the increment of the number of molecules Q j in reaction R j satisfies the following equation:…”

Section: Stochastic Kinetic Equation For Composite Chemicalmentioning

confidence: 99%

“…Equation (18) is a stochastic kinetic equation consisting of S + N random variables. is equation can be solved by the Monte Carlo simulation method (MCSM) [25], the general stochastic differential method (SDM) [23], and the probability density evolution method (PDEM) [39,44]. Here, without loss of generality, the procedure of solving the SKE-CR by using the MCSM is presented:…”

Section: Solution Of the Ske-cr γ(T)mentioning

confidence: 99%

“…e first 6 order eigenvalues and eigenvectors are determined to represent internal fluctuations because the latter eigenvalues are very close to zero. Accordingly, equation (25) becomes the following form:…”

Section: K-l Decomposition On Colored Gaussianmentioning

confidence: 99%

“…e existing stochastic kinetic methods applied in elementary chemical reactions cannot be directly employed to investigate the stochastic dynamical behaviors of composite chemical reaction systems because of the different reaction mechanisms. Moreover, internal fluctuations described by the CLE and CFPE are generally considered as white Gaussian noise [25]. is assumption is only a simplified treatment of internal fluctuations.…”

Section: Introductionmentioning

confidence: 99%

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Stochastic Dynamic Model of Sulfate Corrosion Reactions in Concrete Materials considering the Effects of Colored Gaussian Noises

Zhang

2019

Complexity

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e corrosion reactions in concrete materials subjected to external environment attack can lead to the deterioration of concrete. However, the e ects of internal uctuations on the corrosion reaction process have not been reported in current studies on damage of concrete materials. To comprehensively describe the e ects of internal uctuations, the stochastic dynamic model of corrosion reactions in concrete materials subjected to sulfate attack is established based on the law of mass conservation and random process theory, in which internal uctuations and the parameters of the chemical system are, respectively, regarded as colored Gaussian noises and a series of random variables. An experiment of sulfate corrosion reactions in concrete material is carried out to verify the e ectiveness of the proposed method. Furthermore, the e ects of variations of the initial reactant concentrations on the concentration evolution processes of the corrosion products are investigated. Results show that the stochastic dynamical responses of the corrosion reactions in concrete can be comprehensively investigated by the proposed stochastic mathematical model; the probabilistic information of the corrosion products can also be obtained conveniently. e concentration evolution process of sulfate corrosion products is a random process. e experimental data are only some samples of the random process. Concentrations of the corrosion products in concrete materials signi cantly uctuate with the variations of the initial reactant concentrations.

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Section: Results Analysis Of the Ske-scrmentioning

confidence: 99%

Section: Stochastic Kinetic Equation For Composite Chemicalmentioning

confidence: 99%

Section: Solution Of the Ske-cr γ(T)mentioning

confidence: 99%

Section: K-l Decomposition On Colored Gaussianmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Stochastic Dynamic Model of Sulfate Corrosion Reactions in Concrete Materials considering the Effects of Colored Gaussian Noises

Zhang

2019

Complexity

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Influence of compressive fatigue on the sulfate resistance of slag contained concrete under steam curing

Yan

Yang

Jiang

et al. 2019

Structural Concrete

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This paper investigated the influence of compressive fatigue on the sulfate resistance of slag (0, 20, 50, and 70%) contained concrete under steam curing. After 10,000 cycles loading of 0.5, 0.6, and 0.7 stress level, the concrete was exposed to 5% Na 2 SO 4 for 540 days. The compressive strength, relative dynamic modulus of elasticity (RDME) and SO 4 2− contents were tested after sulfate immersion. Results showed that the standard-cured fatigued concrete had less strength reduction than the steam-cured fatigued concrete during sulfate attack. The steam-cured fatigued concrete containing 20% slag suffered the largest strength reduction, followed by the concrete containing 50, 70, and 0% slag. Compressive fatigue at high stress level (0.7) accelerated the sulfate deterioration of PC standard-cured concrete, while the effect of low stress level (0.5) was minor. The RDME was not a sensitive indicator to access the sulfate resistance of concrete at the beginning of immersion. Compressive fatigue distinctly promoted the sulfate diffusion; the effective SO 4 2− diffusion coefficient was increased when damage occurred in slag concrete. Besides, based on the fatigue damage, an experimental model of the sulfate deterioration of fatigued concrete was proposed. K E Y W O R D S compressive fatigue, slag concrete, steam curing, sulfate resistance

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Simplified Analytical Assessment of Damaged Induced by the External Sulphate Attack in Concrete Piles

Ikumi

Cavalaro

Segura³

et al. 2017

High Tech Concrete: Where Technology and Engineering Meet

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Underground structures and foundations, including piles, constructed with reinforced concrete may be in contact with sulphate-rich soils and water. Structural elements exposed to these conditions may be affected by an expansive process known as external sulphate attack (ESA) that generally leads to an increase in volume, hence displacements and cracking of the concrete. The most widely accepted approach to mitigate such problems is to use cement(s) with a small content of aluminates. The objective of this research was to assess the potential damage induced by ESA using a simplified analytical model that is able to consider parameters such as the cement content and size of the pile, which may also affect the risk of damage. A parametric study was performed with different pile sizes and aluminate and cement contents. The structural integrity of the elements was verified considering a life span of 50 years and three possible failure modes (tensile failure in the core, and shear or tensile failure in the interface between the damaged and undamaged regions). The results suggest that the recommendations based solely on the maximum aluminate content present in the cement are inaccurate and might lead to very different outcomes depending on the characteristics of the elements. The study indicates that other parameters should also be taken into account in order to reduce the risk of ESA in real structures, such as the size of the element or the cement content per unit volume of concrete. This work has implications for the design of pile foundations in ground conditions prone to sulphate attack.

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Simplified methodology to evaluate the external sulfate attack in concrete structures

Abstract: 14The external sulfate attack is a degradation process that causes expansion and cracking 15 in concrete structures. Due to the absence of simplified methodologies to predict the 16 potential damage, codes specify that sulfate resistant cement should be used whenever

Cited by 58 publications

References 29 publications

Stochastic Dynamic Model of Sulfate Corrosion Reactions in Concrete Materials considering the Effects of Colored Gaussian Noises

Stochastic Dynamic Model of Sulfate Corrosion Reactions in Concrete Materials considering the Effects of Colored Gaussian Noises

Influence of compressive fatigue on the sulfate resistance of slag contained concrete under steam curing

Simplified Analytical Assessment of Damaged Induced by the External Sulphate Attack in Concrete Piles

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