Lattice Discrete Particle Modeling of acoustic nonlinearity change in accelerated alkali silica reaction (ASR) tests

Alnaggar, Mohammed; Liu, Minghe; Qu, Jianmin; Cusatis, Gianluca

doi:10.1617/s11527-015-0737-9

Cited by 23 publications

(16 citation statements)

References 95 publications

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“…The model was limited to fully saturated conditions and accounted for the accompanying shrinkage and creep strains at the macroscopic level only. ASR-LDPM was able to explain the experimental results of non-destructive testing of concrete using ultrasonic techniques [67]. The model replicated the change in acoustic nonlinearity parameter and correlated it to the cracking volume and pattern.…”

Section: Introductionmentioning

confidence: 74%

“…Furthermore, as the gel composition and silica content are not known from Ref. [101], a reasonable estimate of κ g =689 kg/m 3 can be obtained based on previous works [64,67]. This means that only κ i , δ c andC 1 i are free parameters.…”

Section: Calibration Of Asr Model Parametersmentioning

confidence: 96%

“…1, it is obvious that, regardless of the sub-scale phenomena that govern the ASR expansion and cracking within the aggregate, a diffusion process at the meso-scale has to happen to transport alkali ions into the aggregate for ASR gel to form and to also transport water for the gel to imbibe and later expand. Considering also, the non-feasible simulation of full 3D structural elements using micro-to nano-scale models, in this study the choice was made to use a meso-scale model (ASR-LDPM) [64,67,73], that would be capable of reflecting the major phenomena at that length scale and average sub-scale ones. ASR-LDPM implements, within the mesoscale framework of LDPM, a model describing ASR gel formation and expansion at the level of each individual aggregate particle.…”

Section: Modeling Asr Expansionmentioning

confidence: 99%

“…Till today, there has been no other model able to replicate these measurements in concrete without any explicit introduction of constitutive relationships relating expansion to damage. The model also was extended to consider alkali nonlinear diffusion and proposed a concentration dependent diffusivity parameter for alkali that accounts for the effect of concrete pore charge on diffusivity [67]. In addition, in his PhD work, Alnaggar [8] also proposed an extension of the ASR-LDPM model to unsaturated conditions and its coupling with creep and shrinkage deformations.…”

Section: Introductionmentioning

confidence: 99%

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Modeling Time-Dependent Behavior of Concrete Affected by Alkali Silica Reaction in Variable Environmental Conditions

Alnaggar¹,

Luzio²,

Cusatis

2017

Preprint

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Alkali Silica Reaction (ASR) is known to be a serious problem for concrete worldwide, especially in high humidity and high temperature regions. ASR is a slow process that develops over years to decades and it is influenced by changes in environmental and loading conditions of the structure. The problem becomes even more complicated if one recognizes that other phenomena like creep and shrinkage are coupled with ASR. This results in synergistic mechanisms that can not be easily understood without a comprehensive computational model. In this paper, coupling between creep, shrinkage and ASR is modeled within the Lattice Discrete Particle Model (LDPM) framework. In order to achieve this, a multi-physics formulation is used to compute the evolution of temperature, humidity, cement hydration, and ASR in both space and time, which is then used within physics-based formulations of cracking, creep and shrinkage. The overall model is calibrated and validated on the basis of experimental data available in the literature. Results show that even during free expansions (zero macroscopic stress), a significant degree of coupling exists because ASR induced expansions are relaxed by meso-scale creep driven by self-equilibriated stresses at the meso-scale. This explains and highlights the importance of considering ASR and other time dependent aging and deterioration phenomena at an appropriate length scale in coupled modeling approaches.

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Section: Introductionmentioning

confidence: 74%

Section: Calibration Of Asr Model Parametersmentioning

confidence: 96%

Section: Modeling Asr Expansionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Modeling Time-Dependent Behavior of Concrete Affected by Alkali Silica Reaction in Variable Environmental Conditions

Alnaggar¹,

Luzio²,

Cusatis

2017

Preprint

Self Cite

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show abstract

“…Lattice discrete particle model is implemented in a computational software named MARS [47] and was used successfully to simulate concrete behavior in different types of laboratory experiments [45]. Furthermore, LDPM has shown superior capabilities in modeling concrete behavior under dynamic loading [28,48], alkali silica reaction deterioration [49][50][51], fracture simulation of fiber reinforced polymers (FRP) reinforced concrete [52], failure of fiber-reinforced concrete [53][54][55], and early age behavior of ultra high performance concrete [30,56,57]. LDPM was also recently formulated to simulate sandstone [58], shale [31,59], and waterless concrete [29].…”

Section: Brief Review Of Lattice Discrete Particle Modelmentioning

confidence: 99%

Proper Orthogonal Decomposition Framework for the Explicit Solution of Discrete Systems With Softening Response

Ceccato

Zhou

Pelessone

et al. 2018

Journal of Applied Mechanics

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The application of explicit dynamics to simulate quasi-static events often becomes impractical in terms of computational cost. Different solutions have been investigated in the literature to decrease the simulation time and a family of interesting, increasingly adopted approaches are the ones based on the proper orthogonal decomposition (POD) as a model reduction technique. In this study, the algorithmic framework for the integration of the equation of motions through POD is proposed for discrete linear and nonlinear systems: a low dimensional approximation of the full order system is generated by the so-called proper orthogonal modes (POMs), computed with snapshots from the full order simulation. Aiming to a predictive tool, the POMs are updated in itinere alternating the integration in the complete system, for the snapshots collection, with the integration in the reduced system. The paper discusses details of the transition between the two systems and issues related to the application of essential and natural boundary conditions (BCs). Results show that, for one-dimensional (1D) cases, just few modes are capable of excellent approximation of the solution, even in the case of stress–strain softening behavior, allowing to conveniently increase the critical time-step of the simulation without significant loss in accuracy. For more general three-dimensional (3D) situations, the paper discusses the application of the developed algorithm to a discrete model called lattice discrete particle model (LDPM) formulated to simulate quasi-brittle materials characterized by a softening response. Efficiency and accuracy of the reduced order LDPM response are discussed with reference to both tensile and compressive loading conditions.

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Symmetric high order microplane model for damage localization and size effect in quasi‐brittle materials

Lale

Cusatis

2021

Num Anal Meth Geomechanics

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This paper presents the so‐called symmetric high‐order microplane (SYHOM) model for the simulation of damage localization and size effect in quasi‐brittle materials. Contrarily to its predecessor, the high order microplane (HOM) model, SYHOM is formulated without rotational degrees of freedom, does not require couple stresses, and solves stability issues created by the antisymmetric components of stress and high order stress tensors. Furthermore, the formulation features variable, damage‐dependent localization limiter and nonlocal characteristic length that allows reproducing correctly size and shape of the fracture process zone during the entire softening process: from crack initiation to the formation of a stress‐free fracture. The paper highlights the implementation of SYHOM via isogeometric analysis with quadratic shape functions and presents several numerical simulations to demonstrate SYHOM's ability to simulate damage evolution during softening. Finally, SYHOM is validated by simulating experimental data relevant to the size effect on structural strength of notched concrete samples.

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Lattice Discrete Particle Modeling of acoustic nonlinearity change in accelerated alkali silica reaction (ASR) tests

Cited by 23 publications

References 95 publications

Modeling Time-Dependent Behavior of Concrete Affected by Alkali Silica Reaction in Variable Environmental Conditions

Modeling Time-Dependent Behavior of Concrete Affected by Alkali Silica Reaction in Variable Environmental Conditions

Proper Orthogonal Decomposition Framework for the Explicit Solution of Discrete Systems With Softening Response

Symmetric high order microplane model for damage localization and size effect in quasi‐brittle materials

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