Deterioration Of Materials Research Articles

Analysis of failure mechanism of concrete pole based on finite element extended method

Concrete poles play an important role in distribution networks and are prone to degradation due to environmental influences. Fracture failures primarily result from structural deterioration, including both damage to the concrete structure under stress overload conditions and the deterioration of the concrete material itself. Due to the lower tensile strength compared to compressive strength, concrete structures often exhibit cracking and fractures. This study initially analyzes the structural deterioration process of concrete electric poles and subsequently develops a damaged model using the finite element method. The results reveal that the maximum tensile strength of concrete electric poles occurs at 2.4 m, while the compression is maximum within the 2–6 m range. Furthermore, an analysis of the main factors contributing to fracture failures and structural deteriorations of these poles is conducted using the finite element extension method. It is determined that shallower crack depths and higher concrete strength enhance fracture resistance and the bearing capacity of concrete poles. Notably, annular cracks at the 2.4 m height are more prone to spreading.

Use of Microwave Tomography Technology for Water Seepage Investigation in Buildings

In metropolitan cities like Hong Kong, it is densely populated and most people live in privately owned premises of reinforced concrete residential buildings. Owing to material deterioration under (a) environmental exposure, (b) poor construction workmanship, (c) lack of proper maintenance and (d) alteration of premises into sub-divided flats with bathrooms, water may seep through the floor slabs of the premises and infiltrate into the subject premises below, and this create nuisance to the subject premises. In this paper, the causes of deterioration of concrete material are elaborated.

Biosurfactants in biocorrosion and corrosion mitigation of metals: An overview

Abstract Biocorrosion, or microbiologically influenced corrosion, is a phenomenon where microorganisms deteriorate the metals. While corrosion is generally considered undesirable due to its negative impact on the integrity and lifespan of materials, the significance of biocorrosion is a major problem because it can cause material deterioration, financial losses, and environmental issues. Conventional corrosion protection techniques frequently use chemicals, which come with risks to human health and the environment. Biosurfactants are surface tension-reducing agents with a low molecular weight that attract many researchers and industrialists due to their excellent chemical properties and stability at extreme temperatures, pH, and under alkaline conditions. These compounds reduce the surface tension of liquids, leading to improved wetting and spreading on metal surfaces. This can help to create a more uniform and protective layer, preventing the accumulation of corrosive agents. This review explores different types of biosurfactants, which include lipopeptides, glycolipids, phospholipids, etc., and how they work to prevent corrosion. The investigation of biosurfactants in corrosion protection not only addresses environmental concerns but also holds promise for innovation in the development of efficient and long-lasting corrosion mitigation strategies for a variety of metal substrates, given the growing demand for green and sustainable technolo gies.

Molybdenum Sulfide Nanoflowers as Electrodes for Efficient and Scalable Lithium-Ion Capacitors.

Hybrid supercapacitors (HSCs) bridge the unique advantages of batteries and capacitors and are considered promising energy storage devices for hybrid vehicles and other electronic gadgets. Lithium-ion capacitors (LICs) have attained particular interest due to their higher energy and power density than traditional supercapacitor devices. The limited voltage window and the deterioration of anode materials upsurged the demand for efficient and stable electrode materials. Two-dimensional (2D) molybdenum sulfide (MoS2) is a promising candidate for developing efficient and durable LICs due to its wide lithiation potential and unique layer structure, enhancing charge storage efficiency. Modifying the extrinsic features, such as the dimensions and shape at the nanoscale, serves as a potential path to overcome the sluggish kinetics observed in the LICs. Herein, the MoS2 nanoflowers have been synthesized through a hydrothermal route. The developed LIC exhibited a specific capacitance of 202.4 F g-1 at 0.25 A g-1 and capacitance retention of >90 % over 5,000 cycles. Using an ether electrolyte improved the voltage window (2.0 V) and enhanced the stability performance. The ex-situ material characterization after the stability test reveals that the storage mechanism in MoS2-LICs is not diffusion-controlled. Instead, the fast surface redox reactions, especially intercalation/deintercalation of ions, are more prominent for charge storage.

Study on the Material Properties and Deterioration Mechanism of Palm Leaves

Abstract Palm leaves are an important carrier for written heritage in southwest China, Tibet, and India. Due to the very nature of the material, many ancient palm leaf manuscripts are facing acidification and other types of degradation. Therefore, scientific research and conservation are of utmost importance. To study material properties and aging mechanisms of palm leaf manuscripts, their basic composition, physical and chemical properties, we studied infrared spectra, internal microstructure, and changes within the structure before and after aging of commonly used local talipot leaves. The results show that aging and deterioration of talipot leaves are mainly due to their acidic production process and high lignin content. The uneven distribution of longitudinal and transverse fiber bundles makes talipot leaves prone to longitudinal splitting. These findings provide important references for the conservation and long-term preservation of palm leaf manuscripts.

A thermodynamic perspective on electrode poisoning in solid oxide fuel cells

A critical challenge to the commercialization of clean and high-efficiency solid oxide fuel cell (SOFC) technology is the insufficient stack lifespan caused by a variety of degradation mechanisms, which are associated with cell components and chemical feedstocks. Cell components related degradation refers to thermal/chemical/electrochemical deterioration of cell materials under operating conditions, whereas the latter regards impurities in feedstocks of oxidant (air) and reductant (fuel). This article provides a thermodynamic perspective on the understanding of the impurities-induced degradation mechanisms in SOFCs. The discussion focuses on using thermodynamic analysis to elucidate poisoning mechanisms in cathodes by impurity species such as Cr, CO2, H2O, and SO2 and in the anode by species such as S (or H2S), SiO2, and P2 (or PH3). The author hopes the presented fundamental insights can provide a theoretical foundation for searching for better technical solutions to address the critical degradation challenges.

Structural Assessment of Late Neolithic Sa Covaccada Dolmen, Sardinia, Italy

ABSTRACT The application of structural engineering tools to archaeological sites is unusual, while architects, archaeologists, and restorers are more commonly involved in these scenarios. Nevertheless, it can provide valuable indications for conservation and repair. This paper presents the structural assessment of the late Neolithic Sa Covaccada Dolmen, in Sardinia, Italy, regarded as a unicum in the Region and one of the most important megalithic monuments in the Mediterranean area. Due to severe material deterioration and extensive crack pattern, structural stability is a primary concern, yet it has not been assessed to date. To address this, both analytical rigid body analyses and 2D and 3D discrete element simulations were performed, contributing to an as challenging as fascinating multidisciplinary restoration project.

Performance of reinforced concrete slabs subjected to simultaneous fire and blast loads

Reinforced concrete (RC) slabs might experience severe damage from multiple hazards such as fire, explosion, and impact during their service life. RC slabs under independent or sequential hazard such as fire or blast loading have been intensively investigated. In reality, fire and explosion often occur simultaneously instead of occurring one after the other as assumed in some previous studies. Simultaneous actions of thermal loading and blast loading on structures are likely to generate different responses or even different response modes and failure mechanisms of structures as compared to independent or sequential actions of the two loads on structures. However, very limited study has been conducted to investigate the performance of RC slabs under simultaneous fire and blast loads. This study investigates the dynamic performance of RC slabs subjected to concurrent fire and blast loads, considering the simultaneous actions of thermal-induced stress, deformation, material deterioration and blast loading. The numerical model is first calibrated with the test results of RC slab under fire or blast loading. With the calibrated numerical model, the effect of thermal stress induced by fire loading on the blast performance is investigated. The influences of fire duration before the occurrence of explosion, as well as the blast loading scenarios and RC slab parameters on the structural responses are investigated. The dynamic responses induced by blast loading after the fire action as usually assumed in the literature are also calculated and compared with those obtained from simultaneous fire and blast loads. Their implications on representing the effects of coupled concurrent fire and blast loads on structural performances are discussed.

Predicting fatigue crack growth rate of cement-based and asphalt paving materials based on indirect tensile cyclic loading tests

Fatigue crack growth rate (FCGR) is a critical indicator that reflects the rate at which material deterioration occurs under cyclic loads. However, there is currently a lack of a mechanistic quantitative analysis and prediction of the FCGR of paving materials under external indirect tensile (IDT) cyclic loads. To address this issue, this study aims to develop a mechanistic model for quantitative analysis and prediction of the FCGR in paving materials subjected to external IDT cyclic loads based on the J-integral based Paris’ law. Two types of paving materials, namely cement-treated aggregates and asphalt mixtures, were selected to demonstrate the results and model of the FCGR. The results indicate that the derived J-integral serves as the driving force for crack growth and is influenced by horizontal tensile stress, initial resilient modulus, damage density, specimen size, and surface energy of the paving materials. The fatigue life of cement-treated aggregates is primarily influenced by the crack initiation stage, while for asphalt mixtures, the crack growth stage plays a more significant role. The application of Paris’ law is found to be effective in predicting the FCGR at stable crack growth stage. The coefficients of Paris’ law exhibit minimal variation across different stress levels and loading frequencies, and can be utilized to evaluate the fatigue crack resistance of different paving materials.

Migration of Water and Salt in Confined Archaeological Complexes: Comprehensive Investigation Below the Third Courtyard of the Prague Castle

ABSTRACT Archaeological complexes and open-air museums must navigate the delicate balance between their societal role and preserving the displayed heritage. Sheltering from atmospheric hazards is a common preservation strategy, yet it introduces new degradation challenges. This study focuses on the persistent material deterioration, heightened moisture content, and salt efflorescence observed in protected excavations beneath Prague Castle’s third courtyard. The objective is to identify and analyse primary sources and pathways of water infiltration, comprehend complex interactions with masonry, and propose conservation strategies to mitigate the degradation. Through detailed field observations, using various moisture sensors, hydrochemical and salt analyses, rainwater emerges as the primary source of damp masonry and the transporting agent of salt-forming ions. Two penetration mechanisms were observed: ingress through perimeter walls and capillary rise where groundwater is present. Evaluation of moisture measurement methods underscores the superiority of the microwave method for historic masonry and the uranine-probe method’s efficacy for capillary water detection. Addressing water infiltration and salt accumulation challenges, we recommend preventive measures: (i) prevent water infiltration, seepage, and ingress; (ii) reduce salt concentrations; and (iii) stabilise site climate to mitigate salt crystallisation transitions. These recommendations extend beyond the study site, offering valuable insights for similar confined archaeological complexes.

La0·8Mn0·2FeO3 impregnated ceramic membrane for membrane fouling elimination via peroxymonosulfate activation

To endow SiC ceramic membranes a catalytic self-cleaning capability, a pore-functionalized SiC ceramic membrane with impregnated a perovskite-type catalyst La0·8Mn0·2FeO3 was fabricated by a urea-assisted one-step combustion method. Diffraction of X-ray (XRD), canning electronic microscopy (SEM) with an energy dispersion X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) were employed to investigate the effects of the impregnating of La0·8Mn0·2FeO3 on SiC membrane pore-structure (La0·8Mn0·2FeO3-CM). The catalytic self-cleaning performance of the as-prepared membranes was assessed through peroxymonosulfate (PMS) activation under a cross-flow filtration mode. Results indicate that La0·8Mn0·2FeO3 has been successfully impregnated into the macropores of SiC membranes without pore blocking, and 92.4 % of the flux recovery rate (FRR) was achieved when the PMS concentration was 70 mM and catalytic flushing time was 45 min. Therefore, the La0·8Mn0·2FeO3 impregnated SiC membrane exhibited excellent catalytic self-cleaning property, which can effectively avoid the environmental pollution and the deterioration of membrane materials caused by chemical cleaning for membrane fouling. In addition, the radical quenching experiment and electron spin resonance (EPR) tests were conducted in the catalytic self-cleaning process, and the results suggested that the hydroxyl radical (⋅OH) and sulfate radical (SO4•‾) are simultaneously captured and ⋅OH is the dominant active species. This study embarks on a novel and environmental friendly membrane cleaning approach for irreversible fouling eliminates in diverse membrane separation applications.

Development of YOLOv8 and Segment Anything Model Algorithm-Based Hanok Object Detection Model for Sustainable Maintenance of Hanok Architecture

A Hanok refers to a traditional Korean architectural structure. Construction structures undergo gradual, rather than instantaneous, transformations due to material degradation and deterioration in joint durability. Moreover, the detection of a structural problem by a nonexpert has severe implications for the safety of the structure. In particular, the precise effects of natural disasters, including storms, earthquakes, heavy snowfall, and structural defects, on structures are hard to determine. Additionally, manuals are limited by their reliance on quantitative assessments, which can pose difficulties for nonspecialists when it comes to recording numerical data. To solve this problem, 3D scanners have been widely employed in evaluating Hanoks, particularly those assigned as cultural heritage by the government. While those assigned as cultural heritage assets are systematically managed by experts and through budgets, the management system for Hanoks inhabited by the public has been overlooked. To fill this gap, this study focused on digital devices that are accessible to nonexperts as replacements for professional 3D scanners. Specifically, data from photos of a Hanok taken with smartphones were extracted to generate objective numerical data. AI training data for Hanoks were used to train the YOLOv8 algorithm and Segment Anything Model (SAM). The leaning values of columns, which constitute a fundamental structural component of a Hanok, were calculated using photographs that precisely captured the columns. The direction and distance of the column’s movement were extracted for visualization. To ensure the reliability of these values, the Hanok under investigation was 3D-scanned. Comparing the numerical values revealed a negligible margin of error, which confirmed the reliability of the photographic data values. Five-tier safety states (good, observation, caution, danger, and very dangerous) were defined based on the column movement distance by analyzing the real measurement data of government-managed Hanoks and used to visualize the structural condition of Hanoks. Therefore, nonexperts can determine the structural safety of a Hanok using objective numerical data, even in situations where its progressive deformation is not readily apparent. Objective numerical analysis based on reliably collected data allows nonexperts to accurately diagnose structural safety, thus facilitating prompt and suitable actions. The results of this study can serve to enhance the stability and longevity of Hanok structures, thus facilitating sustainable maintenance and management.

Metal intrusion enhanced deep learning-based high temperature deterioration analysis of rock materials

The deep learning-based method demonstrates superior capability in high-temperature deterioration analysis of rock materials through scanning electron microscopy (SEM) characterization. However, the blurred boundaries between rock particles and pore structure presented in SEM images always affect the training efficiency. Hence, in this study, the metal intrusion technology and backscattered electron (BSE) observations are applied to assist a deep learning-based model to analyze the deterioration of the rock materials exposed to different levels of high temperatures. >2000 micro images for each level were inputted and trained to distinguish the features of rock after 5 temperature levels deterioration. The results reveal that the classification accuracy on the heat deterioration of the rock materials achieved 94.3%. The classification accuracy under the optimized observation area (from 240 pixels × 240 pixels to 280 pixels × 280 pixels) is stable over 90%, balancing the high precision and training efficiency. Moreover, the interpretable high-temperature degradation characteristics of the micro-damage on rock particles and pore regions can be extracted, enabling further analysis of the degradation process of high-temperature treated rocks. We expect this work will inspire a high-precision, wide-application and cost-efficient method for the deterioration analysis of rock materials in underground projects.

The effect of thermal ageing on electrical and mechanical properties of thermoplastic nanocomposite insulation of power high-voltage cables

This research explores the thermal ageing influence on the Low Density Polyethylene (LDPE) dielectric properties, which is utilised as electrical insulation in high-voltage cables. An accelerated thermal ageing test was done at four temperature ranges ranging from 25 °C to 120 °C to define the degree of material deterioration under thermal ageing and to prevent its failure. LDPE composite samples were made by adding aluminium oxide (Al2O3) inorganic filler in two different grain sizes (nano and micro) with various concentrations. The effect of adding inorganic filler on the acceleration of the thermal ageing of the polymer was studied by heating the samples for different periods of time and measuring the dielectric strength of the samples. The obtained results show that thermal ageing considerably affects the electrical properties of the material. The LDPE/Al2O3 nanofiller sample has the highest dielectric strength value at different temperatures. Thermogravimetric analysis was used to investigate the thermal characteristics of materials. The mechanical characteristics of LDPE polymer are studied using tensile strength and elongation at break tests. References 27, table 4, figures 6.

Water Proofing System in Concrete Structures

Water proof structure is a design concept that aims to repel water and prevent any moisture from seeping into the materials used in construction. This type of structure is particularly important in areas prone to heavy rainfall or flooding, as it helps maintain the integrity and durability of the building. Water proof concrete is formulated with additives and admixtures that create a barrier against water infiltration, making it ideal for areas prone to high levels of humidity or moisture. By incorporating this technology into construction projects, builders can ensure that their structures remain protected from the damaging effects of moisture, such as mold growth, deterioration of building materials, and potential structural issues. The use of abstract damp proof concrete represents a forward-thinking approach to building design and can greatly enhance the durability and longevity of a building.Crystalline admix water proofing with water stops, water proofing with Atactic Polypropylene membrane, and injection are the water proofing systems most commonly used in basements. Using non-shrinking cementitious grout for waterproofing, concrete must have crystalline admixtures made of cementitious powder and water. For toilets in non-sunken places, water proofing with an elastomeric cementitious coating is used. In sunken areas, brick jelly cement concrete with inherent water proofing compound is used.In this paper it deals with the different types of water proofing system..

Quality degradation in glass recycling: substitutability model proposal

The sustainability assessment of waste management systems requires tools capable of evaluating material quality degradation during recycling. Existing research has predominantly focused on the development of substitutability models for plastics, leaving a gap in addressing other materials like glass. Glass is commonly regarded as endlessly recyclable, even though its actual recyclability depends on several crucial factors, such as colour and pollutant contamination. Many Life Cycle Assessment (LCA) studies in this field assume a one-to-one substitution coefficient, neglecting material deterioration and inaccurately representing real-world scenarios. This study proposes and assesses a substitutability model for glass, aiming to measure the replacement extent between virgin materials and recycled crushed glass (cullet). The methodology is based on two key factors: technical quality substitutability, considering impurities and colour contaminations in cullet, and market applicability, accounting for market demand. Once formulated, the model was applied to a European case study on glass waste treatment. Two scenarios were considered: one assuming complete substitution between cullet and raw materials, the other incorporating quality degradation. Findings indicate that, accounting for quality degradation, only 83% of cullet effectively replaces raw materials, resulting in a decrease of the benefit associated with recycling of 13–23% for the different examined impact categories, compared to complete replacement assumption. This underscores the importance of considering quality deterioration in glass recycling impact assessments.

EMI-based monitoring of prestressed concrete beam under chloride-induced corrosion using an embedded piezo sensor

The service life and durability of the prestressed concrete (PC) structures mainly depend on the corrosion resistance of the prestressing strands, wires, or tendons. Once corrosion occurs in the strands, identifying the location and quantifying the phases of corrosion is a very challenging task. Thus, this paper presents a novel way to monitor the corrosion process and identify the deterioration in a PC beam using an embedded piezo sensor (EPS) based on the electro-mechanical impedance (EMI) technique. The accelerated corrosion tests were conducted on a PC beam in which EPS was attached to the prestressing wire inside the beam to monitor the changes in the EMI signature during the corrosion progression. In addition, statistical damage indices such as root mean square deviation is identified to quantify the damage due to corrosion. Further, this study identifies the deterioration in mechanical changes such as stiffness, mass, and damping by extracting the equivalent structural parameters from the raw EMI signatures. Based on qualitative and quantitative results, it is found that the EPS effectively senses the changes at different time intervals during the corrosion process and identifies the damage of corrosion. Also, the equivalent stiffness parameter identified from raw EMI signatures is realistically measuring the material deterioration under corrosion and identifying the corrosion phases. Hence, it is concluded that the EMI technique based on EPS in structural health monitoring of PC beam can accurately assess the deterioration under the effect of corrosion.

Fatigue Behavior and Fracture Surface Analysis of Corroded High-Strength Bridge Cable Wires.

Bridge cable wires suffer from alternating stress and environmental erosion, leading to premature failure prior to its design life. This paper investigates the fatigue and mechanical behaviors of corroded bridge cable wires with a zinc-aluminum (Zn-Al) alloy coating. Based on the salt spray corrosion test and microstructure analysis, the anti-corrosion resistance and corrosion appearance characteristics of the Zn-Al alloy coating and galvanized coating were investigated. The Zn-Al alloy coating was superior in resistance to corrosion fatigue for the improvement in toughness and the generation of anti-corrosion Zn-Al and Fe-Zn-Al phases. Equations of the accelerated corrosion depth of the steel wires had been regressed to roughly estimate the corrosion life of the Zn-Al alloy coating, which can reach 29.1 years with a thickness of 70 μm. The fatigue and mechanical properties of the bare wires after the salt spray test were further studied based on tensile tests and fatigue tests. The fatigue properties of the bridge cable wire would decrease with the corrosion degree due to the deterioration and embrittlement of materials, where ductility characterized by the elongation rate was the most affected. Fracture surfaces of the wires were captured and analyzed based on a method for recognizing graphical contours. Insufficient fatigue life may occur in the steel wires after corrosion and increase with the degree of corrosion. The pit depth logarithmically weakened the fatigue life of steel wires for the weakening of fatigue toughness and the bearing area. The flat fracture was more common with a single fatigue source, while multiple fatigue sources led to step-like fractures for the generation of multiple dispersed crack propagation regions. Corrosion fatigue was more sensitive to the existence of fatigue sources than the reduction. Multiple initiation sources significantly reduced the fatigue life due to the cracking facilitation of the joint effect of multiple pits. The electrochemical reactions of corrosion can lead to material embrittlement and a reducing effect on the fracture toughness of the steel wires.

PbS quantum dot thin film dry etching

Many consumer products used daily contain sensors and image sensors (smartphones, cars, automated tools, etc.). There is a growing demand to enhance the capabilities of industrial products to probe their environment more efficiently, i.e., under difficult conditions (smoke, darkness, etc.). One solution is to extend the capabilities of image sensors to detect light toward the near-infrared and short-wave infrared (SWIR) regions. Because silicon has weak absorption properties in the infrared, especially in the SWIR region, manufacturers are investigating the use of new materials to build these sensors. To this end, colloidal quantum dot (QD) thin films made from the assembly of PbS nanoparticles have emerged as promising materials. They offer tunable bandgaps, favorable absorption properties, and scalability in production. However, patterning the active parts of photodiodes by plasma etching of this new material presents challenges. The etching chemistry must be selected to volatilize Pb and S without modifying the unetched active part of the PbS QD photodiode, and the etching profile should be anisotropic. In this study, we have screened several plasma operating conditions (power, pressure, and temperature) in various chemistries (H2, Cl2, HBr, and N2). To understand the etch mechanisms and profiles, ToF-SIMS and TEM/energy dispersive x-ray were employed. Our findings reveal that halogen-based plasmas cause QD material deterioration through Cl or Br diffusion deep in the film. While H2 plasmas are efficient to etch PbS QD films, they result in high roughness due to the removal of the carbonated ligands that separate PbS QDs. This ligand etching is followed by QD coalescence leading to significant roughness. However, the addition of N2 to H2 can prevent this phenomenon by forming a diffusion barrier at the surface, resulting in favorable etching characteristics.

A New Design Method for Obround Shells

Abstract The design of obround components has been difficult and complex due to the absence of a suitable theoretical solution. Current design codes use empirical formulas based on assumptions to determine the minimum required thickness for obround components. The design process involves iteration. The results obtained are far from accurate. Based on a recently proposed closed-form solution, a new design method for obround components is developed. In the new method, an obround shell is imagined as being stretched laterally from a cylindrical shell or parent cylinder. With the flattened shell increasing, the thickness of the obround shell should increase accordingly, to keep the maximum hoop stress of obround shell consistent with the maximum hoop stress of the parent cylinder. The minimum requested thickness (MRT), of the obround shell is related to the MRT of the parent cylinder and the flattened shell length of the obround shell. Through parametric studies, those relationships are investigated. Empirical expressions are used to describe those relationships. Using the proposed design method, the determination of the MRT of obround members becomes the determination of the MRT of the parent cylinders and additional parameters. The MRT of obround members is determined directly. The case study demonstrates that the proposed method is an efficient and accurate design process for obround members. The use of new method for fitness-for-service was explored. The new method can be used to reassess operational safety in the event of vessel materials' deterioration.