Expansion and deterioration of concrete due to ASR: Micromechanical modeling and analysis

Iskhakov, Tagir; Timothy, Jithender J.; Meschke, Günther

doi:10.1016/j.cemconres.2018.08.001

Cited by 42 publications

(29 citation statements)

References 52 publications

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“…Gel absorbs the moisture and swells generating a pressure which causes microcracking in the aggregates. Such microcracking is characterized by the growth of the penny shaped cracks [4] and is considered to be controlled by the evolution of the ASR gel volume…”

Section: Micromechanics Model For Asr In-mentioning

confidence: 99%

“…In [4] the mechanisms of microcracking of the aggregate as well as of the cement paste matrix were presented, which correspond to the deterioration processes taking place in the concrete with slowly and rapidly reactive aggregates, respectively. However, in this work we consider microcrack propagation only in the slowly reactive aggregates which were used in the experimental program of the project FOR 1498 [5].…”

Section: Micromechanics Model For Asr In-mentioning

confidence: 99%

“…In Section 2 we present and calibrate the model describing moisture and external alkali transport into the concrete pavement. In Section 3 we review the ASR kinetics and ASR induced deterioration modelling approaches developed in [5] and [4], respectively. Finally, in Section 4 we combine all three models together in order to obtain the evolution of microcrack propagation and strains in a concrete pavement.…”

Section: Introductionmentioning

confidence: 99%

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Multiscale modeling of ion transport and ASR induced damage in concrete structures

Iskhakov¹

2019

Proceedings of the 10th International Conference on Fracture Mechanics of Concrete and Concrete Structures

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Alkali-Silica Reaction (ASR) is a detrimental expansive reaction in concrete structures, such as dams and pavements, which substantially limits their structural lifetime. Silica present in the so-called "reactive" aggregates reacts with calcium, hydroxyl and alkali ions of the pore fluid to form a hydrophilic alkali-silica gel. The gel fills pre-existing microcracks in the aggregates and the cement paste and swells in the presence of moisture. The gel pressure induced microcrack growth manifests itself as an expansion at the macroscale. The so-called slow-late ASR damage mechanism initiates at the aggregate scale, leading to concrete degradation in the form of microcracks, which starts in the aggregates and eventually propagates into the cement paste. In order to predict damage and expansion profiles in a concrete pavement a multiscale approach is adopted. The microcracking process that is characterized by linear elastic fracture mechanics and microporomechanics is upscaled by means of mean-field homogenization. Moisture and alkali transport in intact and damaged concrete at the macroscale as well as the diffusion of alkali ions into the aggregate at the microscale is also considered in the model to account for the influence of external alkali and moisture supply on the durability of concrete pavements. The capabilities of the multiscale chemo-mechanical model at different scales are illustrated by comparison with experimental measurements.

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Section: Micromechanics Model For Asr In-mentioning

confidence: 99%

Section: Micromechanics Model For Asr In-mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Multiscale modeling of ion transport and ASR induced damage in concrete structures

Iskhakov¹

2019

Proceedings of the 10th International Conference on Fracture Mechanics of Concrete and Concrete Structures

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“…To predict the process of ASR and its effect on mechanical behavior, numerous models were developed at both the microscopic scale (Dunant and Scrivener 2010;Saouma et al 2015;Iskhakov et al 2019) and the macroscopic scale (Ulm et al 2000). Several macroscopic models have been developed to analyze the structural behavior of RC structures with ASR damage.…”

Section: Introductionmentioning

confidence: 99%

Restraint Effect of Reinforcing Bar on ASR Expansion and Deterioration Characteristic of the Bond Behavior

Tan

et al. 2020

ACT

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To investigate the restraint effect of reinforcing bar on the expansion induced by alkali-silica reaction (ASR), and assess the mechanical behavior of reinforced concrete (RC) structure damaged by ASR, pullout tests of specimens with different ASR expansion were conducted. Accelerated ASR tests of specimens with diameters of 12 mm, 16 mm, and 20mm were conducted to qualify the restraint effect of reinforcing bar. Pullout tests were used to investigate the relationship between nominal bond strength and ASR expansion. Test results show that ASR expansion decreases with the increase of the rebar diameter. Nominal bond strength of specimens increased initially to attain their peak at 14 days, approximately with the expansion of 0.035%. After that, the nominal bond strength decreased near-linearly with the increment of the expansion. A simplified ASR expansion model integrated with the poro-mechanical model was adopted to analyze the restraint effect. The verification of the proposed method was conducted by comparing the analytically predicted results with the test data. The results show that the proposed method could accurately predict both the ASR expansion and bond strength.

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“…Multiscale modeling of damage due to expansive reactions has been investigated by e.g. [10][11][12][13][14] using continuum micromechanics and [15,16] by numerical simulations. We turn to continuum micromechanics which allows an analytical treatment of damage due to microcracking [17][18][19][20][21][22] and of coupling between mechanical damage and transport properties [18,[23][24][25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Micromechanical modelling of damage induced by delayedettringite formation in concrete

et al. 2020

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A multi-scale poromechanical model of damage induced by Delayed Ettringite Formation (DEF) as a consequence of progression of micro-cracks at the fine aggregate scale is developed. The aim is to link the DEF-induced expansion at both the microscopic and macroscopic scales to the loss of stiffness of the mortar and the increase of its diffusion coefficient. At the microscopic scale, mortar is assumed to be constituted of three phases: cement paste, sand and micro-cracks. Damage is assumed to be driven by a free expansion of cement paste due to ettringite crystallization pressures in small capillary pores, at a lower scale. The corresponding homogenised poroelastic properties are estimated along with the diffusion coefficient by resorting either to a Mori-Tanaka scheme or to a self-consistent scheme, as a function of paste and aggregate properties as well as on the density of micro-cracks. The latter is assumed to be an evolving internal variable in order to model DEF-induced damage in the mortar. As the DEF-induced expansive free strain in the cement paste is restrained by the sand particles, internal stresses arise in the mortar. The corresponding free energy can be partially released by an increase in the micro-cracks density by analogy with the energy restitution rate of linear elastic fracture mechanics. The role of the damage criterion adopted on the thermodynamic force associated with micro-cracks density increase is investigated.

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Expansion and deterioration of concrete due to ASR: Micromechanical modeling and analysis

Cited by 42 publications

References 52 publications

Multiscale modeling of ion transport and ASR induced damage in concrete structures

Multiscale modeling of ion transport and ASR induced damage in concrete structures

Restraint Effect of Reinforcing Bar on ASR Expansion and Deterioration Characteristic of the Bond Behavior

Micromechanical modelling of damage induced by delayedettringite formation in concrete

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