ASR/DEF related expansion in structural concrete: Model development and validation

Karthik, Madhu M.; Mander, John B.; Hurlebaus, Stefan

doi:10.1016/j.conbuildmat.2016.10.084

Cited by 24 publications

(9 citation statements)

References 37 publications

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“…with the activation energy of precipitation. To facilitate the calibration of this parameter, the reference temperature can be chosen independently of ℎ, , which is why the normalization term ( ) appears in equation (25). As the literature supplies contradictory tests results for specimens stored at different temperatures during the DEF, the calibration of activation energy…”

Section: Influence Of the Temperature On The Kineticsmentioning

confidence: 99%

“…They are highly nonlinear, as several coupled equations have to be solved simultaneously, and are thus difficult to use in the context of structural analysis in an industrial situation where several thousands of chemical and structural computation have to be performed simultaneously at each node of finite element meshes and at each step of stepwise analysis. From a mechanical point of view, efficient nonlinear models exist to analyse structural behaviour affected by swelling problems [10,23,25,37,38]…”

Section: Introductionmentioning

confidence: 99%

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Chemical modelling of Delayed Ettringite Formation for assessment of affected concrete structures

Sellier

Multon

2018

Cement and Concrete Research

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Delayed Ettringite Formation (DEF) modelling is addressed in the context of structural analysis. First, a chemical model is specified to simulate the effects of the heating of concrete in terms of reactions involving sulfates, aluminates and alkalis. It can be decomposed into: dissolution of primary sulfoaluminates at high temperature, fixation of aluminates in hydrogarnet or carboaluminates, and formation of delayed ettringite at low temperature. The influences of alkalis, temperature and water saturation on these reactions are taken into account. The main result of this model is the amount of delayed ettringite. The parameters of the proposed chemical model are fitted on a large number of experiments taken from the literature. The chemical model is then coupled with a nonlinear mechanical model based on poro-mechanics modelling. An application of chemo-mechanical coupling shows the features and benefits of such modelling to help practitioners in the management of structures affected by DEF.

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Section: Influence Of the Temperature On The Kineticsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Chemical modelling of Delayed Ettringite Formation for assessment of affected concrete structures

Sellier

Multon

2018

Cement and Concrete Research

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“…Comparison between experimental results and model proposed by Karthik et al[46] for uniaxially (a.) and triaxially (b.)…”

mentioning

confidence: 94%

Effects of stress on concrete expansion due to delayed ettringite formation

Thiebaut

Multon

Sellier

et al. 2018

Construction and Building Materials

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Delayed ettringite formation (DEF) is a sulfate attack affecting civil engineering structures. This chemical reaction takes place within the concrete matrix of structures and causes damage in concrete and tension in reinforcements. For managers and owners, the ability to predict and reassess the mechanical behaviour of such structures is a major challenge. The influence of both reinforcements and prestress on DEF expansion were studied in the present work. Several tests were performed in laboratory: expansion under both uni and tri-axial restraint due to reinforcements and expansion under prestress (stress level of 14.5 MPa). Uniaxial restraint led to decreased strain in the restrained direction. For prestressed concrete, the loaded direction exhibited creep strain. In both cases, expansions were not impacted in transversal free directions. Therefore, DEF expansion under uniaxial stress is anisotropic. Cracks were observed parallel to the restrained direction. The final volumetric expansion was lower than in stress-free conditions (decrease of 27% for uni-axially restrained condition). For triaxially restrained tests and prestressed specimens, the volumetric decreases were 56% and 34% respectively. Data provided by these results will be used for numerical reassessment of DEF damaged structures.

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“…Among them, Alkalisilica reaction (ASR) and Delayed Ettringite Formation (DEF) are two very common and important expansion processes [1][2][3][4]. However, with a similar surface cracking pattern, it is difficult to identify and analyze the expansion reasons and their contribution to mechanical properties losses separately [3][4][5]. Besides, experimentations may require several years for the cracking to develop in the laboratory [6][7].…”

Section: Introductionmentioning

confidence: 99%

Fracture simulation of concrete with ASR and DEF expansions by RBSM

Meng¹

2019

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

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In this study, cracking behaviors affected by two main expansion causes: Alkali-silica reaction (ASR) and Delayed ettringite formation (DEF), are predicted by the three-dimensional Rigid Body Spring Model (RBSM). By dissection concrete into 2~3mm randomized polynomial elements and analysis the forces between elements through spring connecting them, RBSM is especially a good solution for fracture analyses. For DEF, initial expansion strain is applied between mortar elements, to reflect the expansion caused by high temperature during curing, which is more concentrated in the inner part where mortar elements experienced higher curing temperature. While in the case of ASR, the expansion strain is applied at the mortar-aggregate interfaces, to reflect the alkali-silica gel formation in and around the aggregates. This is an effective approach to discuss the effect of these two common causes of concrete expansion in long-term, which is difficult to be analyzed using traditional experiment due to its long experiment term required and complexity of quantitatively determinate the contribution of each expansion cause. In this simulation, cracking patterns due to ASR and DEF are well presented. Especially in ASR case, cracks are more localized with expansion given more concentrated. In DEF case, localized crack is well simulated when the expansion is intensified in the center considering the hightemperature zone during the curing.

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ASR/DEF related expansion in structural concrete: Model development and validation

Cited by 24 publications

References 37 publications

Chemical modelling of Delayed Ettringite Formation for assessment of affected concrete structures

Chemical modelling of Delayed Ettringite Formation for assessment of affected concrete structures

Effects of stress on concrete expansion due to delayed ettringite formation

Fracture simulation of concrete with ASR and DEF expansions by RBSM

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