Continuum damage-healing framework for the hydration induced self-healing of the cementitious composite

2020 ◽  
pp. 105678952096803
Author(s):  
Qing Chen ◽  
Xiangyong Liu ◽  
Hehua Zhu ◽  
J Woody Ju ◽  
Xie Yongjian ◽  
...  
Keyword(s):  
Healing Process ◽  
Healing Time ◽  
Continuum Damage ◽  
Self Healing ◽  
Hydration Products ◽  
Cementitious Composite ◽  
Hydration Kinetics ◽  
Micro Cracks ◽  
Damage Healing ◽  
Healing Model

The self-healing materials have become more and more popular due to their active capacity of repairing the (micro-) damages, such as the (micro-) cracks, the (micro-) voids and the other defects. In this paper, the thermodynamic based damage-healing framework is presented for the hydration induced self-healing composite with a compatible healing variable. The new variable is incorporated to consider the time-dependent properties of the hydration products, with which a new damage healing law is proposed. The hydration kinetics are employed to describe the healing process. The properties of the hydration products are arrived with the multiscale and multilevel homogenization scheme. The presented damage-healing model is applied to an isotropic cementitious composite under the tensile loading histories. The presented framework is compared with the classic continuum damage-healing theory and the experimental data. The results show that the presented damage-healing model is capable of describing the hydration induced self-healing of the cementitious composite. It can describe the behavior of the partially and fully healed concrete material. The effects of the healing time and the compatible healing variables on the damage-healing results are investigated based on our proposed framework.

Electrochemical deposition induced continuum damage-healing framework for the cementitious composite

2021 ◽  
pp. 105678952199187
Author(s):  
Hehua Zhu ◽  
Qing Chen ◽  
J Woody Ju ◽  
Zhiguo Yan ◽  
Zhengwu Jiang
Keyword(s):  
Electrochemical Deposition ◽  
Planck Equation ◽  
Healing Time ◽  
Aqueous Environment ◽  
Continuum Damage ◽  
Deposition Method ◽  
Cementitious Composite ◽  
Current Conservation ◽  
Electrochemical Deposition Method ◽  
Damage Healing

The electrochemical deposition method is a promising approach to repair the deteriorated concrete in the aqueous environment. In this paper, a continuum damage-healing framework is presented for the electrochemical deposition method based on the multi-field coupling growth process of the electrochemical deposition products. The ion transportation and the electrode reactions are characterized by employing the Nernst-Planck equation and the current conservation equation. The level set method is adopted to capture the growth of the deposition products. Based on the deposition process, a new empirical healing law is presented, with which a new continuum damage-healing framework is presented for electrochemical deposition method. Numerical examples are conducted by applying the presented framework to the damaged cementitious composite under the tensile loadings. The presented framework is compared with the classic continuum damage-healing theory and the experimental data. The results show that the presented models can describe the electrochemical deposition method induced damage-healing for the cementitious composite. Furthermore, the effects of the healing time, the solution concentration and the external voltage on the damage-healing behaviors are investigated based on our proposed framework.

scholarly journals Smart Self-Healing Capability of Asphalt Material Using Bionic Microvascular Containing Oily Rejuvenator

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6431
Author(s):  
Peng Yang ◽  
Li-Qing Wang ◽  
Xu Gao ◽  
Sai Wang ◽  
Jun-Feng Su
Keyword(s):  
Healing Process ◽  
Healing Time ◽  
The Self ◽  
Asphalt Pavements ◽  
Self Healing ◽  
Microstructure Observation ◽  
Micro Cracks ◽  
Healing Efficiency ◽  
Healing Temperature ◽  
The Individual

It has become one of the research directions of intelligent materials for self-healing asphalt pavements to use a bionic microvascular containing oily rejuvenator. The rejuvenator in a microvascular can carry out the healing of asphalt micro-cracks, thus reducing the damage to and prolonging the life of asphalt pavement. The aim of this work was to investigate the smart self-healing capability of an asphalt/microvascular material through its microstructure and mechanical properties. Microstructure observation indicated no interface separation between the microvasculars and bitumen matrix. Micro-CT images showed that microvasculars dispersed in asphalt samples without accumulation or tangles. The phenomenon of microcracks healing without intervention was observed, which proved that the fractured asphalt sample carried out the self-healing process with the help of rejuvenator diffusing out from the broken microvasculars. The self-healing efficiency of asphalt samples was also evaluated through a tensile test considering the factors of microvasculars content, healing time and healing temperature. It was found that the tensile strength of the asphalt samples was greatly enhanced by the addition of microvasculars under a set test condition. Self-healing efficiency was enhanced with more broken microvasculars in the rupture interface of the asphalt sample. During two self-healing cycles, the self-healing efficiency of the asphalt sample with three microvascular per 1 cm2 of a broken interface were able to reach 80% and 86%. This proves that microvasculars containing rejuvenator play a practical role in the self-healing process of asphalt. With an increase in temperature from 0 to 30 °C, the self-healing capability of the asphalt samples increased dramatically. An increase in time increased the self-healing capability of the bitumen samples. At last, a preliminary mathematical model also deduced that the self-healing efficiency was determined by the individual healing steps, including release, penetration and diffusion of the rejuvenator agent.

A continuum damage-healing model of healing agents based self-healing materials

2017 ◽  
Vol 27 (5) ◽  
pp. 754-778 ◽  
Author(s):  
Yihui Pan ◽  
Fang Tian ◽  
Zheng Zhong
Keyword(s):  
Field Method ◽  
Phase Field Method ◽  
Uniaxial Tensile ◽  
Continuum Damage ◽  
Self Healing ◽  
Pure Bending ◽  
Accumulated Damage ◽  
Uniaxial Tensile Stress ◽  
Damage Healing ◽  
Healing Model

In this paper, a continuum damage-healing model is proposed to interpret the damage-healing phenomenon of healing agents based self-healing materials. The plasticity, damage and healing are respectively described by accumulated plastic strain, damage variable and healing variable. Based on the non-equilibrium thermodynamics and the phase field method, the energy dissipation and corresponding kinetic laws of plasticity, damage and healing are respectively obtained. The healing is motivated by the diffusion of healing agents released by capsules or solute atoms. The corresponding process is described by a diffusion equation with chemical reaction. Furthermore, the threshold and the criteria of damage and healing are established for self-healing materials. The theoretical model is then applied to simulate the healing of concentrated and dispersed damage including the cutting damage, the puncture damage, the homogeneous damage under uniaxial tensile stress and the inhomogeneous damage under pure bending. It is demonstrated that the mechanical loading, the accumulated damage and the diffusion of healing agents work together to govern the healing evolution of self-healing materials.

A Semi-Analytic Solution for Self-Healing Concrete Beams Through Stress Spectral Decomposition

2018 ◽  
Vol 10 (07) ◽  
pp. 1850077
Author(s):  
A. Kazemi ◽  
M. Baghani ◽  
H. Shahsavari ◽  
S. Sohrabpour
Keyword(s):  
Cross Section ◽  
Spectral Decomposition ◽  
Damage Mechanics ◽  
Concrete Beam ◽  
Rectangular Cross Section ◽  
Closed Form Solution ◽  
The Self ◽  
Continuum Damage ◽  
Self Healing ◽  
Damage Healing

Continuum damage-healing mechanics (CDHM) is used for phenomenological modeling of self-healing materials. Self-healing materials have a structural capability to recover a part of the damage for increasing materials life. In this paper, a semi-analytic modeling for self-healing concrete beam is performed. Along this purpose, an elastic damage-healing model through spectral decomposition technique is utilized to investigate an anisotropic behavior of concrete in tension and compression. We drive an analytical closed-form solution of the self-healing concrete beam. The verification of the solution is shown by solving an example for a simply supported beam having uniformly distributed the load. Finally, a result of a self-healing concrete beam is compared to elastic one to demonstrate the capability of the proposed analytical method in simulating concrete beam behavior. The results show that for the specific geometry, the self-healing concrete beam tolerates 21% more weight, and the deflection of the entire beam up to failure load is about 27% larger than elastic solution under ultimate elastic load for both I-beam and rectangular cross-section. Comparison of Continuum Damage Mechanics (CDM) solution with CDHM solution of beam shows that critical effective damage is decreased by 32.4% for a rectangular cross-section and by 24.2% for I-shape beam made of self-healing concrete.

Stochastic micromechanics-based investigations for the damage healing of unsaturated concrete using electrochemical deposition method

2020 ◽  
Vol 29 (9) ◽  
pp. 1361-1378 ◽  
Author(s):  
Q Chen ◽  
HH Zhu ◽  
JW Ju ◽  
HX Li ◽  
ZW Jiang ◽  
...  
Keyword(s):  
Electrochemical Deposition ◽  
Effective Properties ◽  
Healing Process ◽  
Deposition Method ◽  
Computationally Efficient ◽  
Concrete Material ◽  
Aspect Ratios ◽  
Micro Cracks ◽  
Electrochemical Deposition Method ◽  
Damage Healing

The (micro-) cracks or (micro-) voids will lead to the damage of concrete material. A stochastic micromechanical framework is proposed to investigate the damage healing of the unsaturated concrete with the electrochemical deposition method. Stochastic micromechanical representations are presented based on the material’s random microstructures. Differential scheme-based multilevel homogenization procedures are proposed to quantitatively predict the effective properties of the repaired concrete. The probability density functions are obtained for the material’s effective properties with an efficient stochastic simulation framework, which is composed of the univariate approximation for the multivariate function, Newton interpolations and Monte Carlo simulations. Numerical examples are employed to verify the proposed stochastic micromechanical framework, which indicates that the presented framework is computationally efficient and capable of describing the electrochemical deposition method healing process for the unsaturated concrete considering the material’s inherent randomness. Finally, the influences of the saturation degrees and the equivalent aspect ratios on the probabilistic behavior of the repaired concrete are discussed on the basis of the proposed models.

Mechanics of damage, healing, damageability, and integrity of materials: A conceptual framework

2016 ◽  
Vol 26 (1) ◽  
pp. 50-103 ◽  
Author(s):  
George Z Voyiadjis ◽  
Peter I Kattan
Keyword(s):  
Damage Mechanics ◽  
Healing Process ◽  
Continuum Damage Mechanics ◽  
Damage Variable ◽  
Continuum Damage ◽  
Variable Section ◽  
Damage Healing ◽  
Characterization Of Materials ◽  
New Formulation

In this work several new and fundamental concepts are proposed within the framework of continuum damage mechanics. These concepts deal primarily with the nature of the two processes of damage and healing along with introducing a consistent and systematic definition for the concepts of damageability and integrity of materials. Toward this end, seven sections are presented as follows: “The logarithmic damage variable” section introduces the logarithmic and exponential damage variables and makes comparisons with the classical damage variable. In “Integrity and damageability of materials” section a new formulation for damage mechanics is presented in which the two angles of damage–integrity and healing–damageability are introduced. It is shown that both the damage variable and the integrity variable can be derived from the damage–integrity angle while the healing variable and damageability variable are derived from the healing–damageability angle. “The integrity field” section introduces the new concept of the integrity field while “The healing field” section introduces the new concept of the healing field. These two fields are introduced as a generalization of the classical concepts of damage and integrity. “Unhealable damage and nondamageable integrity” section introduces the new and necessary concept of unrecoverable damage or unhealable damage. In this section the concept of permanent integrity or nondamageable integrity is also presented. In “Generalized nonlinear healing” section generalized healing is presented where a distinction is clearly made between linear healing and nonlinear healing. As an example of nonlinear healing the equations of quadratic healing are derived. Finally in “Dissection of the healing process” section a complete and logical/mathematical dissection is made of the healing process. It is hoped that these new and fundamental concepts will pave the way for new, consistent, and holistic avenues in research in damage mechanics and characterization of materials.

ATP Simulation Hybrid Electrode Capacitor Self-Healing Circuit

2013 ◽  
Vol 397-400 ◽  
pp. 1893-1896
Author(s):  
Zhong Hua Kong ◽  
Li Gang Wu ◽  
Zai Fei Luo
Keyword(s):  
Equivalent Circuit ◽  
Healing Process ◽  
Healing Time ◽  
Self Healing ◽  
Plasma Resistance ◽  
Waveform Amplitude

In the paper hybrid electrode capacitor self-healing circuit is simulated through ATP. It illustrates the equivalent circuit of self-healing is correct, so self-healing process can be analysised quantitatively. The results are that the smaller is the plasma resistance, the larger is self-healing waveform amplitude, The larger is the experimental capacitor, the longer is self-healing time.

Bio-inspired self-healing cementitious mortar using Bacillus subtilis immobilized on nano-/micro-additives

2018 ◽  
Vol 30 (1) ◽  
pp. 3-15 ◽  
Author(s):  
Rao Arsalan Khushnood ◽  
Siraj ud din ◽  
Nafeesa Shaheen ◽  
Sajjad Ahmad ◽  
Filza Zarrar
Keyword(s):  
Compressive Strength ◽  
Bacillus Subtilis ◽  
Iron Oxide ◽  
Cement Mortar ◽  
Healing Process ◽  
Main Concern ◽  
Scanning Electron Micrographs ◽  
Self Healing ◽  
Micro Cracks ◽  
Cracked Specimens

Bio-inspired self-healing strategies are much innovative and potentially viable for the production of healable cement mortar matrix. The present research explores the feasibility of gram-positive “Bacillus subtilis” microorganisms in the effective healing of nano-/micro-scale-induced structural and non-structural cracks. The main concern related to the survival of such microorganisms in cementitious environment has been successfully addressed by devising proficient immobilization scheme coherently. The investigated immobilizing media includes iron oxide nano-sized particles, micro-sized limestone particles, and milli-sized siliceous sand. The effect of induced B. subtilis microorganisms immobilized on nano-micro-additives was analyzed by the quantification of average compressive resistance of specimens (ASTM C109) and healing evaluation. The healing process was mechanically gauged by compressive strength regain of pre-cracked specimens after the healing period of 28 days. The pre-cracking load was affixed at 80% of ultimate compressive stress “[Formula: see text]” while the age of pre-cracking was kept variable as 3, 7, 14, and 28 days to precisely correlate healing effectiveness as the function of cracking period. The healing mechanism was further explored by examining the healed micro-crack using field emission scanning electron micrographs, energy dispersive x-ray spectrographs, and thermogravimetry. The results revealed that B. subtilis microorganisms contribute extremely well in the improvement of compressive strength and efficient healing process of pre-cracked cement mortar formulations. The iron oxide nano-sized particles were found to be the most effective immobilizer for preserving B. subtilis microbes till the generation of cracks followed by siliceous sand and limestone particles. The micro-graphical and chemical investigations endorsed the mechanical measurements by evidencing calcite precipitation in the induced nano-/micro-cracks as a result of microbial activity.

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