Modeling of diffusion-reaction behavior of sulfate ion in concrete under sulfate environments

In order to assess theoretically the expansive strain of concrete caused by the ettringite formation and growth under the sulfate attack, some models are proposed to investigate the strain responses of concrete exposed to the sulfate solutions. Firstly, an 1-D nonlinear and nonsteady diffusion-reaction equation of sulfate ion in concrete is proposed; Secondly, based on chemical reactions between sulfate and aluminates in concrete, the expansive strain is obtained due to the ettringite growth resulting in concrete expansion. Thirdly, numerical simulations are carried out to analyze the formation process of the concrete expansive strain under the sulfate solution, and results show that the models can be used to predict the concrete responses with the diffusion time, such as the distribution concentration of sulfate ion, dissipated concentration of the calcium aluminates, expansion strain of concrete due to the formation and growth of ettringite.

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Diffusion reaction behavior in internal tin Nb3Sn wires using Nb/Cu-Ti/Sn-Zn diffusion configuration

IEEE Transactions on Applied Superconductivity ◽

10.1109/tasc.2021.3061035 ◽

2021 ◽

pp. 1-1

Author(s):

Taro Morita ◽

Tsuyoshi Yagai ◽

Nobuya Banno

Keyword(s):

Diffusion Reaction ◽

Reaction Behavior ◽

Zn Diffusion

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Reaction Behavior of Porous TiAl3 Intermetallics Fabricated by Thermal Explosion with Different Particle Sizes

Materials ◽

10.3390/ma14237417 ◽

2021 ◽

Vol 14 (23) ◽

pp. 7417

Author(s):

Kaiyang Li ◽

Tiance Zhang ◽

Yuanzhi Zhu

Keyword(s):

Particle Size ◽

Thermal Explosion ◽

Solid Phase ◽

Raw Materials ◽

Diffusion Reaction ◽

Particle Sizes ◽

Reaction Behavior ◽

Liquid Diffusion ◽

Solid Diffusion ◽

Solid Liquid

Porous TiAl3 intermetallics were prepared by the thermal explosion (TE) and space holder method with different particle sizes of Ti and Al powders, and their reaction behaviors were investigated. The results showed that with the increase in the particle size of the Ti and Al powders, the interfacial contact between the particles decreased, resulting in low interfacial energy and reaction activity, making the process difficult to initiate. Meanwhile, the heat flow rose from 358.37 J/g to 730.17 J/g and 566.74 J/g due to the extension of the solid–liquid diffusion time. The TiAl3 structures obviously expanded, and the formation of connected pore channels promoted the porosity. Only when the Ti and Al particle sizes were both small did the solid–solid diffusion significantly appear. At the same time, the TE reaction weakened, so the product particles had no time to fully grow. This indicates that the particle size of the raw materials controlled the TE reaction process by changing the solid–liquid diffusion reaction time and the degree of solid-phase diffusion.

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Characterization on Solid Phase Diffusion Reaction Behavior and Diffusion Reaction Kinetic of Ti/Al

Rare Metal Materials and Engineering ◽

10.1016/s1875-5372(17)30183-2 ◽

2017 ◽

Vol 46 (8) ◽

pp. 2080-2086 ◽

Cited By ~ 8

Author(s):

Sun Yu ◽

Wan Zhipeng ◽

Hu Lianxi ◽

Wu Binghua ◽

Deng Taiqing

Keyword(s):

Reaction Kinetic ◽

Solid Phase ◽

Diffusion Reaction ◽

Reaction Behavior ◽

Phase Diffusion ◽

And Diffusion

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A thermodynamically consistent chemo-mechanically coupled large deformation model for polymer oxidation

10.31224/osf.io/y7f53 ◽

2019 ◽

Author(s):

Shabnam Konica ◽

Trisha Sain

Keyword(s):

Large Deformation ◽

Diffusion Reaction ◽

Deformation Model ◽

Ambient Conditions ◽

Temperature Oxidation ◽

Reaction Behavior ◽

Oxidative Aging ◽

Consistent Model ◽

Irreversible Effect

In this work, we present a continuum-level thermodynamically consistent model for high temperature oxidation inpolymers, that incorporates the coupling between diffusion, chemical reaction and large deformation behavior ofpolymers. The specific constitutive forms are derived based on the thermodynamic inequality conditions and thekinetics of the oxidative reactions are considered. Oxidative shrinkage has also been considered in the kinematics asan irreversible effect. Subsequently, the model is implemented in ABAQUS/Standard to analyze numerically thecoupled diffusion-reaction behavior of polymers undergoing oxidation. Several numerical simulations are performed tounderstand the effect of various material parameters on the oxidative response. The model is capable of predicting theheterogeneous oxidation profile within a thick polymer sample. It can also track the growth of oxide layer in the case ofa long-term thermo-oxidative aging process. The model can be used to simulate the oxidation process involvingcomplex geometries (as fiber reinforced composites) fairly easily under various ambient conditions.

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Simulations on Sulfate Ion Diffusivity in Concrete Column under Random Excitations

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.261-263.275 ◽

2011 ◽

Vol 261-263 ◽

pp. 275-279 ◽

Cited By ~ 1

Author(s):

Xiao Bao Zuo ◽

Wei Sun

Keyword(s):

Diffusion Coefficients ◽

Concrete Structure ◽

Gradual Increase ◽

Ion Concentration ◽

Diffusion Reaction ◽

Concrete Column ◽

Ion Diffusion ◽

Sulfate Ion ◽

Ion Concentrations ◽

Column Section

This paper presents a 2-D nonlinear and non-steady equation for the diffusion reaction of sulfate ion in concrete column subjected to couplings of random excitations and sulfate attack. Taking the diffusion reaction of sulfate ion in concrete column as an example, the time-variation behaviors of the ion concentration and its diffusion coefficients under white noise excitations are numerically analyzed. The results show that with the increasing of diffusion time, the sulfate ion concentration in the concrete column section has a gradual increase to reach a plateau in which the diffusion and reaction is in dynamical equilibrium state. Under random excitations, the sulfate ion concentrations in the column section increase with the excitation amplitudes, and the sulfate ion diffusion coefficients in concrete change randomly with the excitations and increase with its amplitudes. This work will provide a basis for analyzing the diffusion reaction behaviors of the corrosive medium in concrete structure and the damage evolution of concrete structure durability.

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Observation by HVEM of the martensite transformation and the superconducting transition in Nb3Sn

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100106004 ◽

1988 ◽

Vol 46 ◽

pp. 788-789

Author(s):

M. A. Kirk ◽

M. C. Baker ◽

B. J. Kestel ◽

H. W. Weber

Keyword(s):

Thin Films ◽

Low Temperature ◽

Superconducting State ◽

Martensite Transformation ◽

Sputter Deposition ◽

Diffusion Reaction ◽

Solute Diffusion ◽

Superconducting Transition ◽

Twin Boundaries ◽

Martensite Structure

It is well known that a number of compound superconductors with the A15 structure undergo a martensite transformation when cooled to the superconducting state. Nb3Sn is one of those compounds that transforms, at least partially, from a cubic to tetragonal structure near 43 K. To our knowledge this transformation in Nb3Sn has not been studied by TEM. In fact, the only low temperature TEM study of an A15 material, V3Si, was performed by Goringe and Valdre over 20 years ago. They found the martensite structure in some foil areas at temperatures between 11 and 29 K, accompanied by faults that consisted of coherent twin boundaries on {110} planes. In pursuing our studies of irradiation defects in superconductors, we are the first to observe by TEM a similar martensite structure in Nb3Sn.Samples of Nb3Sn suitable for TEM studies have been produced by both a liquid solute diffusion reaction and by sputter deposition of thin films.

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HREM observations of internetallic alloy formation in Pt-Sn thin films

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100120667 ◽

1992 ◽

Vol 50 (1) ◽

pp. 52-53

Author(s):

D.C. Dufner

Keyword(s):

Thin Films ◽

Cross Sections ◽

Carbon Films ◽

Solid State Reactions ◽

Alloy Formation ◽

Reaction Behavior ◽

Interdiffusion Process ◽

Compositional Changes ◽

General Goal ◽

Film Method

The general goal of this research is to clarify mechanisms of solid state reactions at the atomic level as a step in the rationalization of macroscopic reaction behavior in solids. A study of intermetallic alloy formation resulting from interdiffusion of metals in thin films can be made by HREM. In this work, reactions between Pt and Sn in thin films are studied to elucidate mechanisms for structural and compositional changes during the interdiffusion process.Thin films of Pt and Sn used in this study were prepared by the two-film method introduced by Shiojiri. Few hundred angstroms of Pt were vacuum-deposited onto holey carbon films mounted on TEM grids. Sn films with an average thickness of 200Å were created by evaporation at rates of 15-30 Å/sec onto air-cleaved KBr substrates. The Sn films were wet-stripped and collected on the holey Pt grids. Figure 1 shows a cross-section schematic of a Pt-Sn couple. While this two-film arrangement did not allow observations of the actual reaction interface, microtomy was used to produce cross-sections.

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