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Anticorrosive composite self-healing coating enabled by solar irradiation

《化学科学与工程前沿(英文)》 2022年 第16卷 第9期   页码 1355-1366 doi: 10.1007/s11705-022-2147-1

摘要: Self-healing coatings for long-term corrosion protection have received much interest in recent years. However, most self-healing coatings rely on healants released from microcapsules, dynamic bonds, shape memory, or thermoplastic materials, which generally suffer from limited healing times or harsh conditions for self-healing, such as high temperature and UV radiation. Herein, we present a composite coating with a self-healing function under easily accessible sunlight by adding Fe3O4 nanoparticles and tetradecanol into epoxy resin. Tetradecanol, with its moderate melting point, and Fe3O4 nanoparticles serve as a phase-change component and photothermal material in an epoxy coating system, respectively. Fe3O4 nanoparticles endow this composite self-healing coating with good photothermal properties and a rapid thermal response time under simulated solar irradiation as well as outdoor real sunlight. Tetradecanol can flow to and fill defects by phase transition at low temperatures. Therefore, artificial defects created in this type of self-healing coating can be healed by the liquified tetradecanol induced by the photothermal effect of Fe3O4 nanoparticles under simulated solar irradiation. The healed coating can still serve as a good barrier for the protection of the underlying carbon steel. These excellent properties make this self-healing coating an excellent candidate for various engineering applications.

关键词: self-healing coating     phase transition     photothermal effect     corrosion protection    

Effect of calcium lactate on compressive strength and self-healing of cracks in microbial concrete

Kunamineni VIJAY, Meena MURMU

《结构与土木工程前沿(英文)》 2019年 第13卷 第3期   页码 515-525 doi: 10.1007/s11709-018-0494-2

摘要: This paper presents the effect on compressive strength and self-healing capability of bacterial concrete with the addition of calcium lactate. Compared to normal concrete, bacterial concrete possesses higher durability and engineering concrete properties. The production of calcium carbonate in bacterial concrete is limited to the calcium content in cement. Hence calcium lactate is externally added to be an additional source of calcium in the concrete. The influence of this addition on compressive strength, self-healing capability of cracks is highlighted in this study. The bacterium used in the study is and was added to both spore powder form and culture form to the concrete. spore powder of 2 million cfu/g concentration with 0.5% cement was mixed to concrete. Calcium lactates with concentrations of 0.5%, 1.0%, 1.5%, 2.0%, and 2.5% of cement, was added to the concrete mixes to test the effect on properties of concrete. In other samples, cultured with a concentration of 1×10 cells/mL was mixed with concrete, to study the effect of bacteria in the cultured form on the properties of concrete. Cubes of 100 mm×100 mm×100 mm were used for the study. These cubes were tested after a curing period of 7, 14 and 28 d. A maximum of 12% increase in compressive strength was observed with the addition of 0.5% of calcium lactate in concrete. Scanning electron microscope and energy dispersive X-ray spectroscopy examination showed the formation of ettringite in pores; calcium silicate hydrates and calcite which made the concrete denser. A statistical technique was applied to analyze the experimental data of the compressive strengths of cementations materials. Response surface methodology was adopted for optimizing the experimental data. The regression equation was yielded by the application of response surface methodology relating response variables to input parameters. This method aids in predicting the experimental results accurately with an acceptable range of error. Findings of this investigation indicated the influence of added calcium lactate in bio-concrete which is quite impressive for improving the compressive strength and self-healing properties of concrete.

关键词: calcium lactate     bacillus subtilis     compressive strength     self-healing of cracks    

Computational model generation and RVE design of self-healing concrete

Md. Shahriar QUAYUM,Xiaoying ZHUANG,Timon RABCZUK

《结构与土木工程前沿(英文)》 2015年 第9卷 第4期   页码 383-396 doi: 10.1007/s11709-015-0320-z

摘要: Computational homogenization is a versatile tool that can extract effective properties of heterogeneous or composite material through averaging technique. Self-healing concrete (SHC) is a heterogeneous material which has different constituents as cement matrix, sand and healing agent carrying capsules. Computational homogenization tool is applied in this paper to evaluate the effective properties of self-healing concrete. With this technique, macro and micro scales are bridged together which forms the basis for multi-scale modeling. Representative volume element (RVE) is a small (microscopic) cell which contains all the microphases of the microstructure. This paper presents a technique for RVE design of SHC and shows the influence of volume fractions of different constituents, RVE size and mesh uniformity on the homogenization results.

关键词: homogenization     self-healing concrete (SHC)     representative volume element     multiscale modelling    

Microbial self-healing of cracks in cement-based materials and its influencing factors

《结构与土木工程前沿(英文)》 doi: 10.1007/s11709-023-0986-6

摘要: Cement-based materials are brittle and crack easily under natural conditions. Cracks can reduce service life because the transport of harmful substances can cause corrosion damage to the structures. This review discusses the feasibility of using microbial self-healing agents for crack healing. Tubular and spherical carriers can be used to load microbial self-healing agents and protect microbes, which prolongs the self-healing time. The area self-healing ratio, permeability, mechanical strength, precipitation depth method, numerical modeling, and ultrasonic method can be employed to identify the self-healing effect of cracks. Moreover, the self-healing mechanism is systematically analyzed. The results showed that microbial self-healing agents can repair cracks in cement-based materials in underground projects and dam gates. The difficulties and future development of self-healing cracks were analyzed. A microbial self-healing agent was embedded in the cement-based material, which automatically repaired the developing cracks. With the development of intelligent building materials, self-healing cracks have become the focus of attention.

关键词: cement-based materials     cracks     microbial self-healing agent     mechanism     intelligent building materials    

Computational modeling of fracture in capsule-based self-healing concrete: A 3D study

《结构与土木工程前沿(英文)》 2021年 第15卷 第6期   页码 1337-1346 doi: 10.1007/s11709-021-0781-1

摘要: We present a three-dimensional (3D) numerical model to investigate complex fracture behavior using cohesive elements. An efficient packing algorithm is employed to create the mesoscale model of heterogeneous capsule-based self-healing concrete. Spherical aggregates are used and directly generated from specified size distributions with different volume fractions. Spherical capsules are also used and created based on a particular diameter, and wall thickness. Bilinear traction-separation laws of cohesive elements along the boundaries of the mortar matrix, aggregates, capsules, and their interfaces are pre-inserted to simulate crack initiation and propagation. These pre-inserted cohesive elements are also applied into the initial meshes of solid elements to account for fracture in the mortar matrix. Different realizations are carried out and statistically analyzed. The proposed model provides an effective tool for predicting the complex fracture response of capsule-based self-healing concrete at the meso-scale.

关键词: 3D fracture     self-healing concrete     spherical     cohesive elements     heterogeneous    

The effects of mismatch fracture properties in encapsulation-based self-healing concrete using cohesive-zone

Luthfi Muhammad MAULUDIN, Chahmi OUCIF, Timon RABCZUK

《结构与土木工程前沿(英文)》 2020年 第14卷 第3期   页码 792-801 doi: 10.1007/s11709-020-0629-0

摘要: Finite element analysis is developed to simulate the breakage of capsule in capsule-based self-healing concrete. A 2D circular capsule with different core-shell thickness ratios embedded in the mortar matrix is analyzed numerically along with their interfacial transition zone. Zero-thickness cohesive elements are pre-inserted into solid elements to represent potential cracks. This study focuses on the effects of mismatch fracture properties, namely fracture strength and energy, between capsule and mortar matrix into the breakage likelihood of the capsule. The extensive simulations of 2D specimens under uniaxial tension were carried out to investigate the key features on the fracture patterns of the capsule and produce the fracture maps as the results. The developed fracture maps of capsules present a simple but valuable tool to assist the experimentalists in designing appropriate capsule materials for self-healing concrete.

关键词: self-healing concrete     interfacial zone     capsule materials     cohesive elements     fracture maps    

Preparation, with graphene, of novel biomimetic self-healing microcapsules with high thermal stability

《结构与土木工程前沿(英文)》   页码 1188-1198 doi: 10.1007/s11709-023-0027-5

摘要: This paper reports a comparative study of microcapsules with enhanced thermal stability and electrical conductivity inspired by the bionic thermal insulation of birds’ feathers for self-healing aged asphalt. The work is based on an in situ polymerization with composite shell components of graphene and hexamethoxymethylmelamine resin. By using graphene, microcapsules with rough surfaces are achieved, improving the interface between microcapsules and asphalt. In addition, the microcapsules’ initial thermal decomposition temperature is appropriately high, so that the stability of the microcapsule in the asphalt highway system is protected. The proportion of graphene in the microcapsule shell can regulate the microcapsule’s heat resistance because graphene modifies the shell’s structural makeup. Additionally, the microcapsules’ electrical conductivity is relatively high. The self-healing capability of bitumen sharply increases, providing benefit to the effect of microcapsules on the properties of aged asphalt.

关键词: graphene     microcapsule     bitumen     heat insulation     conductivity    

Using thermodynamic parameters to study self-healing and interface properties of crumb rubber modified

Dongliang HU, Jianzhong PEI, Rui LI, Jiupeng ZHANG, Yanshun JIA, Zepeng FAN

《结构与土木工程前沿(英文)》 2020年 第14卷 第1期   页码 109-122 doi: 10.1007/s11709-019-0579-6

摘要: The thermodynamic property of asphalt binder is changed by the addition of crumb rubber, which in turn influences the self-healing property as well as the cohesion and adhesion within the asphalt-aggregate system. This study investigated the self-healing and interface properties of crumb rubber modified asphalt (CRMA) using thermodynamic parameters based on the molecular simulation approach. The molecular models of CRMA were built with representative structures of the virgin asphalt and the crumb rubber. The aggregate was represented by SiO and Al O crystals. The self-healing capability was evaluated with the thermodynamic parameter wetting time, work of cohesion and diffusivity. The interface properties were evaluated by characterizing the adhesion capability, the debonding potential and the moisture susceptibility of the asphalt-aggregate interface. The self-healing capability of CRMA is found to decrease as the rubber content increases. The asphalt-Al O interface with higher rubber content has stronger adhesion and moisture stability. But the influence of crumb rubber on the interfacial properties of asphalt-SiO interface has no statistical significance. Comparing with the interfacial properties of the asphalt-SiO interface, the asphalt-Al O interface is found to have a stronger adhesion but a worse moisture susceptibility for its enormous thermodynamic potential for water to displace the asphalt binder.

关键词: crumb rubber modified asphalt     surface free energy     self-healing     interface properties     molecular dynamics simulation    

Self-healing polyamide reverse osmosis membranes with temperature-responsive intelligent nanocontainers

《化学科学与工程前沿(英文)》 2023年 第17卷 第9期   页码 1183-1195 doi: 10.1007/s11705-022-2287-3

摘要: Improving the performance of reverse osmosis membranes remains great challenge to ensure excellent NaCl rejection while maintaining high water permeability and chlorine resistance. Herein, temperature-responsive intelligent nanocontainers are designed and constructed to improve water permeability and chlorine resistance of polyamide membranes. The nanocontainer is synthesized by layer-by-layer self-assembly with silver nanoparticles as the core, sodium alginate and chitosan as the repair materials, and polyvinyl alcohol as the shell. When the polyamide layer is damaged by chlorine attack, the polyvinyl alcohol shell layer dissolves under temperature stimulation of 37 °C, releasing inner sodium alginate and chitosan to repair broken amide bonds. The polyvinyl alcohol shell responds to temperature in line with actual operating environment, which can effectively synchronize the chlorination of membranes with temperature response and release inner materials to achieve self-healing properties. With adding temperature-responsive intelligent nanocontainers, the NaCl rejection of thin film composite membrane decreased by 15.64%, while that of thin film nanocomposite membrane decreased by only 8.35% after 9 chlorination cycles. Effective repair treatment and outstanding chlorine resistance as well as satisfactory stability suggest that temperature-responsive intelligent nanocontainer has great potential as membrane-doping material for the targeted repair of polyamide reverse osmosis membranes.

关键词: reverse osmosis     nanocontainer     self-healing     chlorine resistance     water permeability    

A hypothesis for crack free interior surfaces of Longyou caverns caved in argillaceous siltstone 2000 years ago

Zhong Qi YUE, Shaopeng FAN, Zhifa YANG, Lihui LI, Luqing ZHANG, Zhongjian ZHANG,

《结构与土木工程前沿(英文)》 2010年 第4卷 第2期   页码 165-177 doi: 10.1007/s11709-010-0018-1

摘要: Five complete caverns were discovered in Longyou in 1992. They were manually caved in argillaceous siltstone at shallow depths more than 2000 years ago. When they were un-watered, their integrity was maintained completely, and their interior rock surfaces were free of old cracks. Since then, however, the rock’s interior faces have initiated and propagated more and more cracks. This paper attempts to address the question of why the rock interior faces were free of old cracks once they were unearthed. To address this question, this paper proposes a hypothesis that the argillaceous siltstone has the ability of self-healing its cracks over a short period of time under weak acid water environment. Data and evidence are presented herewith to prove the hypothesis. They include observations and measurements in the field and test results in the laboratory. Specifically, a three-point bending test is used to form a tensile crack in a rectangular rock specimen and a dead load test for the specimen immersed in initially weak acid water is used for self-healing its crack. The results have shown that the argillaceous siltstone is in a state of weak alkalinity and the rain water at the site is in a state of weak acidity. Therefore, when it is immersed in weak acid water for some time, the argillaceous siltstone would be able to make chemical reactions to generate new minerals such as calcite. The new minerals would be able to infill the cracks and then heal the crack within a few years. Once the crack is self-healed, the rock can regain its strength and integrity. Consequently, the rock interior surfaces could be free of old cracks when the water was pumped out of the caverns.

关键词: rock cavern     grotto     Longyou     argillaceous siltstone     crack     water     environment     self-healing    

Autogenous healing mechanism of cement-based materials

《结构与土木工程前沿(英文)》   页码 948-963 doi: 10.1007/s11709-023-0960-3

摘要: Autogenous self-healing is the innate and fundamental repair capability of cement-based materials for healing cracks. Many researchers have investigated factors that influence autogenous healing. However, systematic research on the autogenous healing mechanism of cement-based materials is lacking. The healing process mainly involves a chemical process, including further hydration of unhydrated cement and carbonation of calcium oxide and calcium hydroxide. Hence, the autogenous healing process is influenced by the material constituents of the cement composite and the ambient environment. In this study, different factors influencing the healing process of cement-based materials were investigated. Scanning electron microscopy and optical microscopy were used to examine the autogenous healing mechanism, and the maximum healing capacity was assessed. Furthermore, detailed theoretical analysis and quantitative detection of autogenous healing were conducted. This study provides a valuable reference for developing an improved healing technique for cement-based composites.

关键词: autogenous healing     cement-based materials     healing mechanism     aggregation effect    

Plasma-enabled healing of graphene nano-platelets layer

Xiuqi Fang, Carles Corbella, Denis B. Zolotukhin, Michael Keidar

《化学科学与工程前沿(英文)》 2019年 第13卷 第2期   页码 350-359 doi: 10.1007/s11705-018-1787-7

摘要: Graphene platelet networks (GPNs) were deposited onto silicon substrates by means of anodic arc discharge ignited between two graphite electrodes. Substrate temperature and pressure of helium atmosphere were optimized for the production of the carbon nanomaterials. The samples were modified or destroyed with different methods to mimic typical environments responsible of severe surface degradation. The emulated conditions were performed by four surface treatments, namely thermal oxidation, substrate overheating, exposition to glow discharge, and metal coating due to arc plasma. In the next step, the samples were regenerated on the same substrates with identical deposition technique. Damaging and re-growth of GPN samples were systematically characterized by scanning electron microscopy and Raman spectroscopy. The full regeneration of the structural and morphological properties of the samples has proven that this healing method by arc plasma is adequate for restoring the functionality of 2D nanostructures exposed to harsh environments.

关键词: graphene platelet networks     anodic arc discharge     plasma healing     scanning electron microscopy     Raman spectroscopy    

Elastic modulus and thermal stress in coating during heat cycling with different substrate shapes

Daniel GAONA,Alfredo VALAREZO

《机械工程前沿(英文)》 2015年 第10卷 第3期   页码 294-300 doi: 10.1007/s11465-015-0351-0

摘要:

The elastic modulus of a deposit (Ed) can be obtained by monitoring the temperature (?T) and curvature (?k) of a one-side coated long plate, namely, a one-dimensional (1D) deformation model. The aim of this research is to design an experimental setup that proves whether a 1D deformation model can be scaled for complex geometries. The setup includes a laser displacement sensor mounted on a robotic arm capable of scanning a specimen surface and measuring its deformation. The reproducibility of the results is verified by comparing the present results with Stony Brook University Laboratory’s results. The ?k-?T slope error is less than 8%, and the Ed estimation error is close to 2%. These values reveal the repeatability of the experiments. Several samples fabricated with aluminum as the substrate and 100MXC nanowire (Fe and Cr alloy) as the deposit are analyzed and compared with those in finite element (FE) simulations. The linear elastic behavior of 1D (flat long plate) and 2D (squared plate) specimens during heating/cooling cycles is demonstrated by the high linearity of all ?k-?T curves (over 97%). The Ed values are approximately equal for 1D and 2D analyses, with a median of 96 GPa and standard deviation of 2 GPa. The correspondence between the experimental and simulated results for the 1D and 2D specimens reveals that deformation and thermal stress in coated specimens can be predicted regardless of specimen geometry through FE modeling and by using the experimental value of Ed. An example of a turbine-blade-shaped substrate is presented to validate the approach.

关键词: in-plane     Young’s modulus     curvature temperature     thermal stress     coating    

Plasma spray coating on interconnector toward promoted solid oxide fuel cells and solid oxide electrolysis

《能源前沿(英文)》 doi: 10.1007/s11708-023-0901-9

摘要: Interconnector is a critical component to construct solid oxide cells (SOCs) stack. Oxidation of metallic interconnectors and Cr poisoning caused by oxidation are important factors that lead to long-term performance degradation of SOCs. Coating on the interconnector surface is an important approach to inhibit the oxidation and Cr migration of the interconnector. Herein, (La0.75Sr0.25)0.95MnO3–δ (LSM) and Mn1.5Co1.5O4 (MCO) are used to fabricate the coatings of interconnector. Two advanced thermal spray technology, atmospheric plasma spraying (APS) and low-pressure plasma spray (LPPS), are adopted for the coating preparation. The electrochemical performance, rising and cooling cycle stability, and Cr diffusion inhibition performance of the coatings are tested and evaluated. The result indicates that MCO can generate more uniform and denser coatings than LSM. In addition, MCO coatings prepared by LPPS shows the best electrochemical performance, rising and cooling cycle stability, and Cr diffusion inhibition. The initial area specific resistance (ASR) is 0.0027 Ω·cm2 at 800 °C. After 4 cooling cycle tests, the ASR increases to 0.0032 Ω·cm2 but lower than other samples. Meanwhile, the relative intense of Cr at the interface of SUS430 with MCO coatings fabricated by LPPS is lower than that of MCO fabricated by APS after 4 rising and cooling cycle operations, showing more favorable Cr diffusion inhibition performance.

关键词: interconnector coating     plasma spray     electrochemical performance     Cr diffusion inhibition     solid oxide cells (SOCs)    

Erratum to: Enhancing the photoelectrochemical performance of p-silicon through TiO coating decorated

《能源前沿(英文)》 2022年 第16卷 第5期   页码 876-877 doi: 10.1007/s11708-022-0832-x

标题 作者 时间 类型 操作

Anticorrosive composite self-healing coating enabled by solar irradiation

期刊论文

Effect of calcium lactate on compressive strength and self-healing of cracks in microbial concrete

Kunamineni VIJAY, Meena MURMU

期刊论文

Computational model generation and RVE design of self-healing concrete

Md. Shahriar QUAYUM,Xiaoying ZHUANG,Timon RABCZUK

期刊论文

Microbial self-healing of cracks in cement-based materials and its influencing factors

期刊论文

Computational modeling of fracture in capsule-based self-healing concrete: A 3D study

期刊论文

The effects of mismatch fracture properties in encapsulation-based self-healing concrete using cohesive-zone

Luthfi Muhammad MAULUDIN, Chahmi OUCIF, Timon RABCZUK

期刊论文

Preparation, with graphene, of novel biomimetic self-healing microcapsules with high thermal stability

期刊论文

Using thermodynamic parameters to study self-healing and interface properties of crumb rubber modified

Dongliang HU, Jianzhong PEI, Rui LI, Jiupeng ZHANG, Yanshun JIA, Zepeng FAN

期刊论文

Self-healing polyamide reverse osmosis membranes with temperature-responsive intelligent nanocontainers

期刊论文

A hypothesis for crack free interior surfaces of Longyou caverns caved in argillaceous siltstone 2000 years ago

Zhong Qi YUE, Shaopeng FAN, Zhifa YANG, Lihui LI, Luqing ZHANG, Zhongjian ZHANG,

期刊论文

Autogenous healing mechanism of cement-based materials

期刊论文

Plasma-enabled healing of graphene nano-platelets layer

Xiuqi Fang, Carles Corbella, Denis B. Zolotukhin, Michael Keidar

期刊论文

Elastic modulus and thermal stress in coating during heat cycling with different substrate shapes

Daniel GAONA,Alfredo VALAREZO

期刊论文

Plasma spray coating on interconnector toward promoted solid oxide fuel cells and solid oxide electrolysis

期刊论文

Erratum to: Enhancing the photoelectrochemical performance of p-silicon through TiO coating decorated

期刊论文