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Accepted Author ManuscriptApplied Mechanic

A review of ASR modeling approaches for finite element analysis of dams and bridges

In this paper the anisotropic behavior of ASR swelling is simulated through a 1D smeared crack model. The choice of the engineering properties is discussed, in particular for the evolution of the tensile strength and the Young’s modulus during the swelling. The last one is used as the main indicator for ASRrelated damage. The model is hampered by the lack of experimented data available in literature. The outlook of the approach is that orthotropic stiffness degradation could be used to explain anisotropic swelling.Structural EngineeringCivil Engineering and Geoscience

Simulating the deteriorating effect of the alkali-silica reaction in concrete via a micro-poro fracture mechanical model

harvestApplied Mechanic

Measuring and modelling the deteriorating impact of Alkali-Silica Reaction in concrete on the mechanical characteristics

Unaffected and ASR-affected concrete, experimentally, appear as substantially different materials. Since the material characterization is one of the main points of attention within a structural assessment, the deteriorating impact of ASR on concrete in terms of both expansion and degradation of the mechanical properties is studied. Both experimental and modelling approaches are followed.Applied Mechanic

Ageing effects of alkali-silica reaction in concrete structures

The alkali-silica reaction (ASR) is a long-term deterioration process, which produces a hydrophilic and expansive gel causing damage. The ASR acts on concrete as an ageing phenomenon, modifying the material on the basis of its stress state. Focussing on the mechanical degradation of concrete, estimated trends for the mechanical properties in free expansive affected concrete arepresented. These show the result of recent research which collected and statistically analysed laboratory tests on 54 concrete mixes performed by 11 authors. Comparable findings are also obtained through a multiscale material model, which aims to capture the micro and macro aspects of the problem. The ASR-affected concrete is seen as an evolving material, whose state should be followed over time taking into account chemomechanical coupling.Applied Mechanic

Literature review of modelling approaches for ASR in concrete: a new perspective

The assessment of concrete structures affected by alkali–silica reaction (ASR) is a complex problem due to the multiscale nature of this long-term phenomenon. The reaction starts within the concrete constituents and developed at aggregate level by inducing swelling and deterioration of concrete material, which eventually affect the capacity of the structure. Due to this multiscale nature of the phenomenon, the problem is studied by various researchers in numerous manners. In this paper, a literature review of the main modelling approaches for ASR in concrete is presented within a new perspective. The models are categorised on the basis of their input and output parameters, instead of adopting the classical classification on the base of the scale (e.g. micro, meso and macro). The main aim of the review is to understand to which extent the available models are able to describe the deteriorating impact induced by ASR in concrete material and if the approaches can ultimately be extended to structural analyses.Applied Mechanic

A multiscale micromechanical approach to model the deteriorating impact of alkali-silica reaction on concrete

The alkali-silica reaction (ASR) in concrete is one of the most harmful deterioration processes, which leads to expansion and cracking of the material. To understand the evolution of ASR in concrete and its deteriorating impact on the material, a multiscale material model, from aggregate to concrete level, is proposed. The concrete, which at macro scale is considered a homogeneous material, is micromechanically modelled by a matrix-cracks system, in which each phase is uniform and behaves elastically. The damage criterion, associated to the cracks, is formulated on the basis of linear fracture mechanics theory. The model, which is analytically solved, is based on a limited numbers of input parameters, to be determined via micro and macro experimental investigations. The model is able to predict the non-linear behaviour of concrete subject to uniaxial loading in good agreement with code formulations, which are usually input for numerical analyses of structures. For the case of ASR-affected material, the model overestimates the degradation rate of mechanical properties as a function of the expansion. On the contrary, the relationship between stiffness and strength deterioration is correctly approximated. Various model modifications are explored suggesting that the assumption of elastic behaviour of each phase should be reconsidered.Applied Mechanic

Degradation of the mechanical properties in ASR-affected concrete: Overview and modeling

The Alkali-Silica Reaction (ASR) can generate harmful effects in the concrete structures. In this paper the degradation of the mechanical properties of ASR-affected concrete is studied by comparing the experimental results available in literature. An overview of the macroscopic material modelling approaches related to this aspect is given. Eventually, a 1D crack model is proposed to model structures subjected to swelling. Fracture energy dissipation due to swelling or to external loading is treated in an integrated way.Structural EngineeringCivil Engineering and Geoscience

Multiscale material model for asr-affected concrete structures

One of the most harmful degradation process for concrete structures is the alkali-silica reaction. This process starts at aggregate level with a gel swelling and can produce damage up to macro level, by compromising the integrity and capacity of the structure. In order to better understand the complex nature of this phenomenon, a multiscale material modeling approach is presented. The aim of the model is to capture the coupled effect between chemical and mechanical loading on stiffness, strength and expansion. To this end the chemical loading is driven by a gel production, within a micromechanical damage model. After summarizing the main features on the model, a numerical example illustrates the use of the model for uniaxial tensile tests.Structural EngineeringCivil Engineering and Geoscience

Towards structural modelling of alkali-silica reaction in concrete

Structures affected by Alkali-Silica Reaction (ASR) include large massive concrete dams and bridges, which are considered essential for the infrastructure system, and not easily replaceable. The main feature of this reaction is the creation of a hydrophobic expansive gel which causes internal damage in the concrete. This damage is strongly related to the macroscopic stress state. Vice versa, the caused damage can have macroscopic consequences. Therefore a structural model should be able to capture the chemo-mechanical coupling induced by the swelling. For this purpose a multiscale material model is chosen to represent the ASR-affected concrete behaviour in structures. In this paper the motivations which brought the authors to this choice are explained.Applied Mechanic