Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 194
Filter
1.
Int J Oral Maxillofac Implants ; 0(0): 1-25, 2024 Aug 01.
Article in English | MEDLINE | ID: mdl-39093290

ABSTRACT

PURPOSE: The objective of this study was to examine how the saline and acidic environment affects the mechanical integrity of narrow single-body titanium implants for oral rehabilitation. MATERIALS AND METHODS: Thirty titanium-base alloy implants with 2.5 mm diameter were placed into a polyacetal holder and coupled to a stainless-steel prosthetic cap for fatigue testing in three different environments, as follows: dry air; saline solution (pH at 7.6); and lactic acid solution (pH at 3.4). The fracture surfaces were analyzed using a Scanning Electron Microscope (SEM). Also, finite element analysis was carried out to estimate the maximum von Mises stresses. RESULTS: The fatigue resistance was higher in the group tested in dry air (60%), followed by saline solution (30%) and lactic acid (10%). Regardless of the environment, fracture occurred at the same region of the failed specimens in line with the highest stress concentration spots, according to the finite element analysis. SEM analyses revealed two distinct failure regions, both with the presence of fatigue streaks: fatigue and overload. A high incidence of secondary cracks was also noticed on the specimens exposed to the solutions. CONCLUSIONS: The present study revealed that both saline and acidic solutions significantly affect the fatigue resistance of narrow dental implants. Critical regions of the narrow implants were also susceptible to cracks and plastic deformation that should be taken into consideration in planning for oral rehabilitation.

2.
Discov Nano ; 19(1): 123, 2024 Aug 06.
Article in English | MEDLINE | ID: mdl-39105979

ABSTRACT

Resin cement integrated with zein-incorporated magnesium oxide nanoparticles has previously been found to inhibit oral microbes and decrease bacterial biofilm. However, the bond strength and surface features of this biomaterial have yet to be investigated. The objective of this study was to evaluate the shear bond strength, mode of fracture, and surface roughness of resin cement modified with zein-incorporated magnesium oxide nanoparticles. Characterization of the cement was performed by X-ray diffraction, field emission scanning electron microscopy, and Fourier transform infrared spectroscopy. 126 human teeth were divided into 3 groups and cemented to lithium disilicate ceramic using resin cement with zein-incorporated magnesium oxide nanoparticles at concentrations of 0%, 1%, and 2% (n = 42). 21 samples of each group were subjected to the shear bond strength test, while the other 21 underwent thermocycling for 10,000 cycles before the test, after which all samples were evaluated for the mode of fracture. To assess surface roughness, resin cement disks were analyzed by a profilometer before and after undergoing thermocycling for 10,000 cycles. The shear bond strength of the cement with 1% and 2% nanoparticles was significantly higher than the control before thermocycling. The mode of fracture was found to be mainly adhesive with all groups, with the unmodified cement presenting the highest cohesive failure. There was no significant difference in surface roughness between the groups before or after thermocycling. The addition of zein-incorporated magnesium oxide nanoparticles to resin cement improved or maintained the shear bond strength and surface roughness of the resin cement.

3.
Materials (Basel) ; 17(14)2024 Jul 11.
Article in English | MEDLINE | ID: mdl-39063711

ABSTRACT

This article presents a case of complex investigation of defects of lime mortar and plaster that have been developing over a period of 48 years in a house in Prague and are strongly influenced by thermal and salt crystallization cycles. The aim of this research was to describe the degradation phenomena of mortars and plasters observed on a narrowly limited part of the building, combining structural elements of different types and ages and to explain the mechanisms of their formation and development. The geometric characteristics of the defects were determined by non-destructive methods, especially optical interference moiré, laser profilometry, photogrammetry, and infrared thermography. Material data were determined on samples by electron microscopy, ion exchange chromatography, and direct moisture content measurements. The results supported the hypothesis of the increase in the deformation of large buckles of detached plasters by the mechanism of buckling caused by loading of the edges with compression generated by volume changes. Direct loading of the boundary surfaces causes the formation of bulges in the confined areas. This study shows the importance of failure analysis of real structures to gain knowledge about the behavior of structures and materials under long-term service conditions.

4.
Article in English | MEDLINE | ID: mdl-39078287

ABSTRACT

OBJECTIVE: Conduct a scoping review of research studies that describe rule-based clinical decision support (CDS) malfunctions. MATERIALS AND METHODS: In April 2022, we searched three bibliographic databases (MEDLINE, CINAHL, and Embase) for literature referencing CDS malfunctions. We coded the identified malfunctions according to an existing CDS malfunction taxonomy and added new categories for factors not already captured. We also extracted and summarized information related to the CDS system, such as architecture, data source, and data format. RESULTS: Twenty-eight articles met inclusion criteria, capturing 130 malfunctions. Architectures used included stand-alone systems (eg, web-based calculator), integrated systems (eg, best practices alerts), and service-oriented architectures (eg, distributed systems like SMART or CDS Hooks). No standards-based CDS malfunctions were identified. The "Cause" category of the original taxonomy includes three new types (organizational policy, hardware error, and data source) and two existing causes were expanded to include additional layers. Only 29 malfunctions (22%) described the potential impact of the malfunction on patient care. DISCUSSION: While a substantial amount of research on CDS exists, our review indicates there is a limited focus on CDS malfunctions, with even less attention on malfunctions associated with modern delivery architectures such as SMART and CDS Hooks. CONCLUSION: CDS malfunctions can and do occur across several different care delivery architectures. To account for advances in health information technology, existing taxonomies of CDS malfunctions must be continually updated. This will be especially important for service-oriented architectures, which connect several disparate systems, and are increasing in use.

5.
Heliyon ; 10(13): e34202, 2024 Jul 15.
Article in English | MEDLINE | ID: mdl-39071613

ABSTRACT

Predictive maintenance to avoid fatigue and failure enhances the reliability of mechanics, herewith, this paper explores vibrational time-domain data in advancing fault diagnosis of predictive maintenance. This study leveraged a belt-drive system with the properties: operating rotational speeds of 500-2000 RPM, belt pretensions at 70 and 150 N, and three operational cases of healthy, faulty and unbalanced, which leads to 12 studied cases. In this analysis, two one-axis piezoelectric accelerometers were utilized to capture vibration signals near the driver and pulley. Five advanced statistics were calculated during signal processing, namely Variance, Mean Absolute Deviation (MAD), Zero Crossing Rate (ZCR), Autocorrelation Coefficient, and the signal's Energy. The Taguchi method was used to test the five selected features on the basis of Signal-to-Noise (S/N) ratio. For classifications, an expert system was used based on artificial intelligence where a Random Forest (RF) model was trained on untraditional parameters for optimizing the accuracy. The resulted 0.990 and 0.999, accuracy and AUC, demonstrate the RF model's high dependability. Evidently, the methodology highlights the features potential when progressed into expert systems, which advances predictive maintenance strategies for belt-drive systems.

6.
Heliyon ; 10(13): e33623, 2024 Jul 15.
Article in English | MEDLINE | ID: mdl-39035504

ABSTRACT

In the production of castings, residual stresses arise in the cooling process, the level of which is often unknown. Their significance in engineering practice is very important because they are superposed on the stresses from the service load and are often the primary cause of material failure leading to failure of the equipment or structure. Their quantification using numerical simulations is rather difficult because many variables enter into the calculation simulating technological processes. Therefore, residual stress levels are most often determined in such cases by experimental measurement and, if possible, by monitoring and evaluating the history of parameter changes due to changes in the input parameters. In the present paper, the results of experimental measurements of residual stresses in synthetic cast iron castings are presented, where the effect of Ti microalloying on residual stress levels was assessed. Based on the comparison of the results obtained experimentally on castings made from grey cast iron, it can be concluded that the addition of Ti metal reduced the residual stress levels while maintaining the tensile strength and hardness HB.

7.
Micromachines (Basel) ; 15(6)2024 Jun 09.
Article in English | MEDLINE | ID: mdl-38930742

ABSTRACT

This paper presents a comprehensive study on single- and repetitive-frequency UIS characteristics of 1200 V asymmetric (AT) and double trench silicon carbide (DT-SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs) and their electrical degradation under electrical-thermal working conditions, investigated through experiment and simulation verification. Because their structure is different, the failure mechanisms are different. Comparatively, the gate oxide of a DT-MOSFET is more easily damaged than an AT-MOSFET because the hot carriers are injected into the oxide. The parameters' degradation under repetitive UIS stress also requires analysis. The variations in the measured parameters are recorded to evaluate typical electrical features of device failure. Furthermore, TCAD simulation is used to reveal the electrothermal stress inside the device during avalanche. Additionally, failed devices are decapsulated to verify the location of the failure point. Finally, a new type of stepped-oxide vertical power DT MOSFET with P-type shielding and current spread layers, along with its feasible process flow, is proposed for the improvement of gate dielectric reliability.

8.
Polymers (Basel) ; 16(12)2024 Jun 17.
Article in English | MEDLINE | ID: mdl-38932072

ABSTRACT

The 6935M Sprint Quattro Secure S and 6947M Sprint Quattro Secure are high voltage leads designed to administer a maximum of 40 joules of energy for terminating ventricular tachycardia or ventricular fibrillation. Both leads utilize silicone insulation and a polyurethane outer coating. The inner coil is shielded with polytetrafluoroethylene (PTFE) tubing, while other conductors are enveloped in ethylene tetrafluoroethylene (ETFE), contributing to the structural integrity and functionality of these leads. Polyurethane is a preferred material for the outer insulation of cardiac leads due to its flexibility and biocompatibility, while silicone rubber ensures chemical stability within the body, minimizing inflammatory or rejection responses. Thirteen implantable cardioverter defibrillator (ICD) leads were obtained from the Wright State University Anatomical Gift Program. The as-received devices exhibited varied in vivo implantation durations ranging from less than a month to 89 months, with an average in vivo duration of 41 ± 27 months. Tests were conducted using the Test Resources Q series system, ensuring compliance with ASTM Standard D 1708-02a and ASTM Standard D 412-06a. During testing, a load was applied to the intact lead, with careful inspection for surface defects before each test. Results of load to failure, percentage elongation, percentage elongation at 5 N, ultimate tensile strength, and modulus of elasticity were calculated. The findings revealed no significant differences in these parameters across all in vivo exposure durations. The residual properties of these ICD leads demonstrated remarkable stability and performance over a wide range of in vivo exposure durations, with no statistically significant degradation or performance changes observed.

9.
Saudi Dent J ; 36(5): 770-777, 2024 May.
Article in English | MEDLINE | ID: mdl-38766294

ABSTRACT

Purpose: This study aimed to perform a thorough failure analysis of two fractured narrow dental implants after medium-term in vivo use. Materials and methods: The top parts of two fractured Narrow Dental Implant (NDI) fixtures were retrieved from two different locations at two different times from the same patient. The NDI-specimen-1 was 12-months in service while the NDI-specimen-2 was 17-months in service. In both cases, the top parts of the fractured NDI fixtures that were attached to prosthetic components were retrieved and subjected to thorough, non-destructive and destructive testing. Results: Light Microscopy (LM) and Scanning Electron Microscopy (SEM) revealed that both the retrieved fractured NDIs failed because of fatigue, characterized by beach and ratchet marks. Macroscopic examination revealed that fatigue cracks initiated at the internal thread surfaces of the implants and propagated around them until final fracture. Both samples fractured near the end of the retaining screw and followed the root of the internal thread. Optical and SEM analyses revealed a uniform distribution of irregularly shaped grains (diameter = 2 to 5 µm). X -ray Energy Dispersive Spectroscopy (EDS) analysis showed that the NDI-specimen-1 was made using Ti-14%Zr with a Vickers Hardens (HV) of 288 ± 5. Conclusion: Since the fracture occurred by a fatigue; thus, an increase in fatigue resistance will be beneficial for the longevity of NDI.

10.
Int J Oral Maxillofac Implants ; 0(0): 1-29, 2024 May 03.
Article in English | MEDLINE | ID: mdl-38717354

ABSTRACT

PURPOSE: One-size implant-abutment (OSIA) connection systems have been developed for simplicity of clinical use and for a range of implant diameters. The aim of this in vitro study was to investigate the rotational load fatigue performance of different implant diameters and abutment platforms of an OSIA connection system. METHODOLOGY: Narrow, regular and wide diameter implants were tested with Regular Base (RB/WB) abutments of an OSIA system (Straumann. BLX). Wide diameter implants were also tested with Wide Base (WB) abutments. This resulted in 4 test groups (n=5): N-RB/WB (Narrow, 3.5mm, RB/WB abutment), R-RB/WB (Regular, 4.0mm, RB/WB abutment), W-RB/WB (Wide, 5.0mm, RB/WB abutment) and W-WB (Wide, 5.0mm, WB abutment). A rotational load fatigue machine applied a sinusoidally varying stress at an angle of 45o, producing an effective bending moment of 35Ncm at a frequency of 10 Hz in air at 20 oC. The number of cycles to failure was recorded. Results were evaluated using ANOVA. Failed specimens were examined with SEM to evaluate the failure mode. Pristine specimens were sectioned to examine the implant-abutment connection. RESULTS: All specimens in the 3 test groups with RB/WB abutments failed within the range of 558,750 cycles to 4,497,619 cycles, while the W-WB test group reached the upper limit of 5 million cycles without failure. Significant difference was found between abutment platforms (P < .001). There were no significant differences found for implant diameters (P =.857). However, with increasing implant diameter, implant fracture was less common and the location of failure was more coronal and consistently at the level of the implant platform for the abutment, and at the screw neck. CONCLUSIONS: For wide diameter implants, WB abutments exhibited a superior fatigue performance than RB/WB abutments, and would be preferred in situations of high mechanical risk. Increasing implant diameter, when used with RB/WB abutments, did not improve fatigue performance due to the one-size prosthetic connection, but failures were less catastrophic, and coronally located, which may be advantageous in managing failures.

11.
Patterns (N Y) ; 5(5): 100965, 2024 May 10.
Article in English | MEDLINE | ID: mdl-38800362

ABSTRACT

Artificial intelligence has substantially improved the efficiency of data utilization across various sectors. However, the insufficient filtering of low-quality data poses challenges to uncertainty management, threatening system stability. In this study, we introduce a data-valuation approach employing deep reinforcement learning to elucidate the value patterns in data-driven tasks. By strategically optimizing with iterative sampling and feedback, our method is effective in diverse scenarios and consistently outperforms the classic methods in both accuracy and efficiency. In China's wind-power prediction, excluding 25% of the overall dataset deemed low-value led to a 10.5% improvement in accuracy. Utilizing just 42.8% of the dataset, the model discerned 80% of linear patterns, showcasing the data's intrinsic and transferable value. A nationwide analysis identified a data-value-sensitive geographic belt across 10 provinces, leading to robust policy recommendations informed by variances in power outputs and data values, as well as geographic climate factors.

12.
Materials (Basel) ; 17(9)2024 Apr 23.
Article in English | MEDLINE | ID: mdl-38730749

ABSTRACT

In the present study, the stability and failure phenomena of thin-walled constructions subjected to axial compression, featuring a central cut-out, and constructed from composite materials were explored. These constructions were fabricated from a carbon-epoxy composite using the autoclave method. The research encompassed experimental assessments on actual specimens alongside numerical analyses employing the finite element approach within the ABAQUS® software. The investigation spanned the entire load spectrum up to the point of structural failure, incorporating both practical trials and simulation analysis. During the practical assessments, the study monitored the post-buckling response and captured acoustic emissions to thoroughly evaluate the composite's failure mechanisms. Additionally, the ARAMIS system's non-invasive three-dimensional scanning was employed to assess deformations. Theoretical simulations utilized a step-by-step failure analysis, initiating with failure onset as per Hashin's theory and proceeding to failure progression based on an energy criterion. The simulation outcomes, particularly concerning the critical and post-critical phases, were juxtaposed with empirical data to identify the composite's vulnerability zones. The comparison underscored a significant concordance between the simulation predictions and the empirical findings.

13.
Materials (Basel) ; 17(9)2024 Apr 24.
Article in English | MEDLINE | ID: mdl-38730790

ABSTRACT

The knowledge of the mechanical behavior of a 3D-printed material is fundamental for the 3D printing outbreaking technology to be considered for a range of applications. In this framework, the significance, reliability, and accuracy of the information obtained by testing material coupons assumes a pivotal role. The present work focuses on an evaluation of the static mechanical properties and failure modes of a 3D-printed short carbon fiber-reinforced polyamide in relation to the specimen's unique meso-structural morphology and water content. Within the manufacturing limitations of a commercially available printer, specimens of dedicated combinations of geometry and printing patterns were specifically conceived and tested. The specimens' meso-structure morphologies were investigated by micro-computed tomography. The material failure mechanisms were inferred from an analysis of the specimens' fracture surfaces and failure morphologies. The outcomes of the present analysis indicate that each test specimen retained proper mechanical properties, thereby suggesting that they should be accurately designed to deliver representative information of the underlying material beads or of their deposition layout. Suggestions on the adoption of preferred test specimens for evaluating specific material properties were proposed.

14.
ACS Appl Mater Interfaces ; 16(19): 24464-24472, 2024 May 15.
Article in English | MEDLINE | ID: mdl-38710103

ABSTRACT

Potassium-sulfur (K-S) batteries are one of the promising high-energy-density candidates beyond current lithium-ion batteries. Nevertheless, in practice, the utilization of K-S batteries is largely hindered due to the dissolution and shuttle effect of the cathode redox intermediates and the scarcity of an effective anode protection layer in conventional electrolytes. Herein, electrolyte engineering is applied to formulate an ether-based localized high-concentration electrolyte (LHCE) for the first time in a K-S cell with the mitigated parasitic effect of polysulfide dissolution and shuttle and the tuned anode-electrolyte interface property. A nonsolvating and polysulfide-stable fluoroether is sieved as a cosolvent in such an LHCE, which possesses the ultralow polysulfides solubility due to less roaming solvents and thus alleviates the polysulfides shuttle effect. The anion-derived solid electrolyte interphase enriched in inorganic components is constructed due to the strengthened cation-anion interplay in the primary solvation sheath and highlighted with accelerated interfacial kinetics in a K-S cell. It is validated that the proposed LHCE unlocks the theoretical capacity of the K-S cell based on the conversion between S and K2S3. It is further revealed that the lifespan is limited to the anode corrosion with severe cosolvent degradation caused by limited solvating solvent compatibility with metallic K, and the inevitable byproduct accumulation at the S cathode. The K-S cell based on the designed LHCE could achieve a prolonged lifespan with a reversible capacity of 448 mA h/gs after 80 cycles with an elaborate cathode design. This work shines a light on the electrolyte design perspective for full utilization and an in-depth mechanistic understanding of high-energy-density K-S batteries.

15.
Materials (Basel) ; 17(3)2024 Feb 02.
Article in English | MEDLINE | ID: mdl-38591572

ABSTRACT

Based on the classical grid theory and related regulations, a structure model of a fiber-wound composite gas cylinder was designed in this paper. Based on the design results, a finite element model of a fully wound composite cylinder of an aluminum alloy inner liner with a working pressure of 35 MPa was established based on the ABAQUS software, and its stress distribution under working pressure and minimum burst pressure was analyzed. According to engineering experience, the pressure tolerance of composite cylinders can be improved by proper autofrettage pressure before working pressure, so the influence of autofrettage pressure was analyzed in this paper. The optimum autofrettage pressure was selected by setting the autofrettage gradient, and damage analysis was carried out on the cylinder with nominal working pressure of 35 MPa based on the Hashin failure criterion. The results show the initial damage sequence: matrix stretching occurs before the fiber stretching, and the damage generally starts from the spiral-wound layer. The tensile damage first appears in the transition section between the head and the barrel body, and the damage of the spiral-wound layer develops from the inner layer of the wound layer to the outer layer, while the damage of the circumferentially wound layer develops from the outer layer to the inner layer.

16.
Sci Total Environ ; 927: 172407, 2024 Jun 01.
Article in English | MEDLINE | ID: mdl-38608910

ABSTRACT

The escalating expansion of urban subway systems in recent years has accentuated the issue of stray current corrosion within pipeline networks, emerging as a critical concern for urban safety. This paper delves into the intricate interplay between these phenomena, employing data-driven statistical analyses to elucidate the coupling characteristics between subway lines and the occurrence of failures in adjacent buried pipelines. An advanced three-dimensional finite element model was developed for stray current corrosion in pipelines, seamlessly integrating empirical data and physics-based modeling, which is to uncover the spatial nuances and multifaceted impacts on subway pipeline corrosion from both macro and micro perspectives under varying influencing factors. The study unveils a pronounced geographical and functional affinity between urban subway networks and metallic pipeline networks. The coupling attributes between subway systems and pipelines, such as distance, angle, and pipeline-specific characteristics including material and age, assume pivotal roles. The results further emphasize the hierarchical order of influence, with stray current intensity holding the greatest sway, followed by the distance between subway and pipelines, the angle between them, and soil resistivity. This paper offers a comprehensive investigation of the interrelationships and influential factors between subway systems and adjacent pipelines. It contributes to the mitigation and management of stray current corrosion in pipelines induced by nearby rail transit, thereby enhancing the resilience of both subway and pipeline networks within urban areas.

17.
Materials (Basel) ; 17(7)2024 Mar 25.
Article in English | MEDLINE | ID: mdl-38612005

ABSTRACT

Snow failure is the process by which the stability of snow or snow-covered slopes is destroyed, resulting in the collapse or release of snow. Heavy snowfall, low temperatures, and volatile weather typically cause consequences in Antarctica, which can occur at different scales, from small, localized collapses to massive avalanches, and result in significant risk to human activities and infrastructures. Understanding snow damage is critical to assessing potential hazards associated with snow-covered terrain and implementing effective risk mitigation strategies. This review discusses the theoretical models and numerical simulation methods commonly used in Antarctic snow failure research. We focus on the various theoretical models proposed in the literature, including the fiber bundle model (FBM), discrete element model (DEM), cellular automata (CA) model, and continuous cavity-expansion penetration (CCEP) model. In addition, we overview some methods to acquire the three-dimensional solid models and the related advantages and disadvantages. Then, we discuss some critical numerical techniques used to simulate the snow failure process, such as the finite element method (FEM) and three-dimensional (3D) material point method (MPM), highlighting their features in capturing the complex behavior of snow failure. Eventually, different case studies and the experimental validation of these models and simulation methods in the context of Antarctic snow failure are presented, as well as the application of snow failure research to facility construction. This review provides a comprehensive analysis of snow properties, essential numerical simulation methods, and related applications to enhance our understanding of Antarctic snow failure, which offer valuable resources for designing and managing potential infrastructure in Antarctica.

18.
Materials (Basel) ; 17(8)2024 Apr 10.
Article in English | MEDLINE | ID: mdl-38673086

ABSTRACT

PC/ABS composites are commonly used in airbag covers. In this paper, uniaxial tensile experiments of a PC/ABS composite at different temperatures and strain rates were conducted. The results showed that the temperature and loading rate affect the mechanical properties of the PC/ABS composite. As the temperature increases, the yield stress decreases and the strain at the moment of fracture increases, but the strain rate at the same temperature has a relatively small effect on the mechanical properties, which are similar to ductile materials. The experimental results were applied to the Abaqus model which considered thermal effects and the exact Johnson-Cook constitutive parameters were calculated by applying the inverse method. Based on the constitutive model and the failure analysis findings acquired by DIC, the uniaxial tensile test at the room temperature and varied strain rates were simulated and compared to the test results, which accurately reproduced the test process. The experiment on target plate intrusion of the PC/ABS composite was designed, and a finite-element model was established to simulate the experimental process. The results were compared with the experiments, which showed that the constitutive and the failure fracture strains were valid.

19.
Polymers (Basel) ; 16(7)2024 Apr 08.
Article in English | MEDLINE | ID: mdl-38611276

ABSTRACT

A set of polymer composite bolted T-joints with a novel configuration consisting of an internal skeleton and external skin was fabricated using a prepreg-RTM co-curing molding process. Experiments were conducted to study their mechanical properties under a bending load. A finite element model with a polymer resin area between the skin and skeleton was established and verified by the experimental results. Then, the damage propagation process and failure mechanism of the joint and the influence of three factors related to the layer characteristics of the skin and skeleton were investigated by the validated models. The results show that the bending stiffness and the yield limit load of the novel composite T-joint are 0.81 times and 1.65 times that of the 2A12 aluminum T-joint, respectively, while at only 55.4% of its weight. The damage of the joint is initiated within the resin area and leads to the degradation of the joint's bending performance. The preferred stacking sequence of the skeleton is [0/+45/90/-45]ns when primarily subjected to bending loads. The decrease in the bending performance is within 5% of the inclining angle of the skeleton, less than 12 degrees. The more 90° layers in the skin, the better the bending performance of the joints, while the more 0° layers, the poorer the bending performance.

20.
Heliyon ; 10(5): e26655, 2024 Mar 15.
Article in English | MEDLINE | ID: mdl-38434391

ABSTRACT

Addressing the enormous waste resulting from discarded worn rubber tires is an environmental challenge. Recycling and using crushed rubber tire waste (CRTW) in construction materials can help in addressing this challenge. This study investigates the effect of addition of CRTW on the engineering properties of high plasticity clay soils (HPCS). There is a paucity of research in the application of CRTW in HPCS. This research tries to fill this research gap. Specifically, this study seeks to investigate the effect of mixing CRTW on the constitutive properties of HPCS. After identifying a locally available HPCS, mixtures of the clay and several percentages (0%, 6%, 12%, 18%, and 24%) by weight of CRTW were prepared. A range of CRTW shapes and sizes were investigated. Three different particle shapes of CRTW (granular rubber, rubber chips, and rubber fiber), and two particle sizes (fine and coarse) were studied. The parameters studied included unconfined compressive strength (UCS), strain at failure, post-peak strength loss (PPSL), modulus of elasticity, failure modes/mechanisms, repeatability of tests results, and examination of CRTW particles and mixtures via binocular and SEM microscope. Our findings unveiled that the highest level of repeatability was observed in granular CRTW, with a maximum variability of only 5%. Moreover, the mixtures containing granular CRTW exhibited, on average, 10% and 15% higher strength and modulus of elasticity, respectively, in comparison to mixtures incorporating other shapes of CRTW. In general, the HPCS-CRTW mixtures displayed higher shear strains, averaging 25% greater than pure HPCS. Furthermore, the addition of CRTW to HPCS resulted in a reduction of its PPSL and a transition in behavior from brittle to slightly ductile. Examination of failed specimens revealed the existence of two primary failure modes: shear plane failure and shear plane failure accompanied by multiple vertical cracks within the mixtures. These results suggest that the utilization of granular CRTW in HPCS can improve certain properties of HPCS. However, it is advisable to limit the rubber content in this mixture to 6% to mitigate significant adverse effects on its strength.

SELECTION OF CITATIONS
SEARCH DETAIL