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Keywords = cracking fracture toughness

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22 pages, 6962 KiB  
Article
Suppression of Delamination in CFRP Laminates with Ply Discontinuity Using Polyamide Mesh
by M. J. Mohammad Fikry, Keisuke Iizuka, Hayato Nakatani, Satoru Yoneyama, Vladimir Vinogradov, Jun Koyanagi and Shinji Ogihara
J. Compos. Sci. 2025, 9(8), 414; https://doi.org/10.3390/jcs9080414 - 4 Aug 2025
Abstract
Carbon fiber-reinforced plastics (CFRPs) offer excellent in-plane mechanical performance, but their relatively low interlaminar fracture toughness makes them vulnerable to delamination, particularly around intralaminar discontinuities such as resin-rich regions or fiber gaps. This study investigates the effectiveness of polyamide (PA) mesh inserts in [...] Read more.
Carbon fiber-reinforced plastics (CFRPs) offer excellent in-plane mechanical performance, but their relatively low interlaminar fracture toughness makes them vulnerable to delamination, particularly around intralaminar discontinuities such as resin-rich regions or fiber gaps. This study investigates the effectiveness of polyamide (PA) mesh inserts in improving interlaminar toughness and suppressing delamination in CFRP laminates with such features. Two PA mesh configurations were evaluated: a fully embedded continuous layer and a 20 mm cut mesh strip placed between continuous and discontinuous plies near critical regions. Fracture toughness tests showed that PA mesh insertion improved interlaminar toughness approximately 2.4-fold compared to neat CFRP, primarily due to a mechanical interlocking mechanism that disrupts crack propagation and enhances energy dissipation. Uniaxial tensile tests with digital image correlation revealed that while initial matrix cracking occurred at similar stress levels, the stress at which complete delamination occurred was approximately 60% higher in specimens with a 20 mm mesh and up to 92% higher in specimens with fully embedded mesh. The fully embedded mesh provided consistent delamination resistance across the laminate, while the 20 mm insert localized strain redistribution and preserved global mechanical performance. These findings demonstrate that PA mesh is an effective interleaving material for enhancing damage tolerance in CFRP laminates with internal discontinuities. Full article
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28 pages, 6702 KiB  
Article
Mechanistic Insights into the Fracture Toughness Enhancement of Nano-TiO2 and Basalt Fiber Bar Reinforced Magnesium Phosphate Cement
by Wei-Kang Li, Sheng-Ai Cui, Yu-Peng Li, Ya-Lei Zeng, Guang Zeng and Wei Xia
Nanomaterials 2025, 15(15), 1183; https://doi.org/10.3390/nano15151183 - 1 Aug 2025
Viewed by 244
Abstract
Magnesium phosphate cement (MPC) exhibits brittleness when utilized as a repair material for bridge decks. To address this issue, this study employs nano-TiO2 (NT) and a novel material (basalt fiber bar) as modifiers. A double-K fracture model is developed for the modified [...] Read more.
Magnesium phosphate cement (MPC) exhibits brittleness when utilized as a repair material for bridge decks. To address this issue, this study employs nano-TiO2 (NT) and a novel material (basalt fiber bar) as modifiers. A double-K fracture model is developed for the modified MPC to quantitatively evaluate the enhancement of fracture toughness induced by NT and basalt fiber bars. The cracking behavior and toughening mechanisms of the NT and basalt fiber bar reinforced MPC are investigated using extended finite element theory and composite material theory. Additionally, a formula is proposed to calculate the incremental fracture toughness of NT and basalt fiber bar reinforced MPC. The results indicated that NT and basalt fiber bar can effectively enhance the ultimate bending capacity of MPC. The improvement increases with the fiber volume fraction, and noticeable bending hardening occurs when the fiber content exceeds 2%. With the same fiber volume fraction, the peak load can be increased by up to 11.7% with the addition of NT. The crack initiation toughness of the NT group without basalt fiber bars is 58% higher than that of the CC group. The content and diameter of basalt fiber bar are critical parameters affecting the toughness of the NT and basalt fiber bar reinforced MPC. Full article
(This article belongs to the Special Issue Nanomodification of Civil Engineering Materials)
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19 pages, 7574 KiB  
Article
Effect of Natural Fiber Characteristics on Properties of Cementitious Composites: A Comparison of Recycled Pulp from Beverage Cartons, Bamboo, and Eucalyptus Fibers
by Phouthanouthong Xaysombath, Nattakan Soykeabkaew, Darunee Wattanasiriwech and Suthee Wattanasiriwech
Constr. Mater. 2025, 5(3), 50; https://doi.org/10.3390/constrmater5030050 - 31 Jul 2025
Viewed by 132
Abstract
This study evaluates the influence of fiber type, geometry, and interfacial behavior on the physical and mechanical performance of cementitious composites reinforced with recycled pulp from beverage cartons (RPBC), bamboo fiber (BF), and eucalyptus fiber (EF) as the sole reinforcing agents. The BF [...] Read more.
This study evaluates the influence of fiber type, geometry, and interfacial behavior on the physical and mechanical performance of cementitious composites reinforced with recycled pulp from beverage cartons (RPBC), bamboo fiber (BF), and eucalyptus fiber (EF) as the sole reinforcing agents. The BF was rounded in shape and had the highest aspect ratio, while the ribbon-shaped EF exhibited the highest tensile strength index. The RPBC fibers were fibrillated and the shortest, with a ribbon shape. Flexural strength results showed that RPBCC achieved a maximum strength that was 47.6% higher than the control specimen (0% fiber), outperforming both BF- and EF-reinforced counterparts. This superior performance is attributed to the higher fibrillation level of the ribbon-shaped RPBC fibers, which promoted better fiber–matrix bonding. As the fiber content increased, the bulk density of EFC and BFC decreased linearly, while RPBC composites showed only a modest decrease in density. Porosity steadily increased in EFC and BFC, whereas a non-linear trend was observed in RPBCC, likely due to its unique morphology and fibrillation. Conversely, EFC exhibited significantly higher maximum fracture toughness (3600 J/m2 at 10 wt.%) compared to PBFCC (1600 J/m2 at 14 wt.%) and BFC (1400 J/m2 at 14 wt.%). This enhancement is attributed to extensive fiber pullout mechanisms and increased energy absorption during crack propagation. Overall, all composite types demonstrated flexural strength values above 4 MPa, placing them in the Grade I category. Those reinforced with 10–14% RPBC exhibited strengths of 11–12 MPa, categorizing them as Grade II according to ASTM C1186-02. Full article
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18 pages, 8192 KiB  
Article
Microstructure, Mechanical Properties, and Tribological Behavior of Friction Stir Lap-Welded Joints Between SiCp/Al–Fe–V–Si Composites and an Al–Si Alloy
by Shunfa Xiao, Pinming Feng, Xiangping Li, Yishan Sun, Haiyang Liu, Jie Teng and Fulin Jiang
Materials 2025, 18(15), 3589; https://doi.org/10.3390/ma18153589 - 30 Jul 2025
Viewed by 221
Abstract
Aluminum matrix composites provide an ideal solution for lightweight brake disks, but conventional casting processes are prone to crack initiation due to inhomogeneous reinforcement dispersion, gas porosity, and inadequate toughness. To break the conventional trade-off between high wear resistance and low toughness of [...] Read more.
Aluminum matrix composites provide an ideal solution for lightweight brake disks, but conventional casting processes are prone to crack initiation due to inhomogeneous reinforcement dispersion, gas porosity, and inadequate toughness. To break the conventional trade-off between high wear resistance and low toughness of brake disks, this study fabricated a bimetallic structure of SiCp/Al–Fe–V–Si aluminum matrix composite and cast ZL101 alloy using friction stir lap welding (FSLW). Then, the microstructural evolution, mechanical properties, and tribological behavior of the FSLW joints were studied by XRD, SEM, TEM, tensile testing, and tribological tests. The results showed that the FSLW process homogenized the distribution of SiC particle reinforcements in the SiCp/Al–Fe–V–Si composites. The Al12(Fe,V)3Si heat-resistant phase was not decomposed or coarsened, and the mechanical properties were maintained. The FSLW process refined the grains of the ZL101 aluminum alloy through recrystallization and fragmented eutectic silicon, improving elongation to 22%. A metallurgical bond formed at the joint interface. Tensile fracture occurred within the ZL101 matrix, demonstrating that the interfacial bond strength exceeded the alloy’s load-bearing capacity. In addition, the composites exhibited significantly enhanced wear resistance after FSLW, with their wear rate reduced by approximately 40% compared to the as-received materials, which was attributed to the homogenized SiC particle distribution and the activation of an oxidative wear mechanism. Full article
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26 pages, 23183 KiB  
Article
Fracture Behaviour of Basalt Fibre-Reinforced Lightweight Geopolymer Concrete: A Multidimensional Analysis
by Jutao Tao, Mingxia Jing, Qingshun Yang and Feng Liang
Materials 2025, 18(15), 3549; https://doi.org/10.3390/ma18153549 - 29 Jul 2025
Viewed by 259
Abstract
This study introduced basalt fibres as a reinforcing material and employed notched beam three-point bending tests combined with digital image correlation (DIC) technology to comprehensively evaluate key fracture parameters—namely, initial fracture toughness, unstable fracture toughness, fracture energy, and ductility index—of expanded polystyrene (EPS)-based [...] Read more.
This study introduced basalt fibres as a reinforcing material and employed notched beam three-point bending tests combined with digital image correlation (DIC) technology to comprehensively evaluate key fracture parameters—namely, initial fracture toughness, unstable fracture toughness, fracture energy, and ductility index—of expanded polystyrene (EPS)-based geopolymer concrete with different mix proportions. The results demonstrate that the optimal fracture performance was achieved when the basalt fibre volume content was 0.4% and the EPS content was 20%, resulting in respective increases of 12.07%, 28.73%, 98.92%, and 111.27% in the above parameters. To investigate the toughening mechanisms, scanning electron microscopy was used to observe the fibre–matrix interfacial bonding and crack morphology, while X-ray micro-computed tomography enabled detailed three-dimensional visualisation of internal porosity and crack development, confirming the crack-bridging and energy-dissipating roles of basalt fibres. Furthermore, the crack propagation process was simulated using the extended finite element method, and the evolution of fracture-related parameters was quantitatively analysed using a linear superposition progressive assumption. A simplified predictive model was proposed to estimate fracture toughness and fracture energy based on the initial cracking load, peak load, and compressive strength. The findings provide theoretical support and practical guidance for the engineering application of basalt fibre-reinforced EPS-based geopolymer lightweight concrete. Full article
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14 pages, 2206 KiB  
Article
Numerical Simulation Study on the Fracture Process of CFRP-Reinforced Concrete
by Xiangqian Fan, Jueding Liu, Li Zou and Juan Wang
Buildings 2025, 15(15), 2636; https://doi.org/10.3390/buildings15152636 - 25 Jul 2025
Viewed by 188
Abstract
To investigate the crack extension mechanism in CFRP-reinforced concrete, this paper derives analytical expressions for the external load and crack opening displacement in the fracture process of CFRP concrete beams based on the crack emergence toughness criterion and the Paris displacement formula as [...] Read more.
To investigate the crack extension mechanism in CFRP-reinforced concrete, this paper derives analytical expressions for the external load and crack opening displacement in the fracture process of CFRP concrete beams based on the crack emergence toughness criterion and the Paris displacement formula as the theoretical basis. A numerical iterative method was used to computationally simulate the fracture process of CFRP-reinforced concrete beams and to analyze the effect of different initial crack lengths on the fracture process. The research results indicate that the numerical simulation results of the crack initiation load are in good agreement with the test results, and the crack propagation curves and the test results are basically consistent before the CFRP-concrete interface peels off. The numerical results of ultimate load are lower than the test results, but it is safe for fracture prediction in actual engineering. With the increase in the initial crack length, the effect of the initial crack length on the critical effective crack propagation length is more obvious. Full article
(This article belongs to the Section Building Materials, and Repair & Renovation)
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19 pages, 7948 KiB  
Article
Comparative Analysis of Fracture Mechanics Parameters for Wrought and SLM-Produced Ti-6Al-7Nb Alloy
by Ivan Gelo, Dražan Kozak, Nenad Gubeljak, Tomaž Vuherer, Pejo Konjatić and Marko Katinić
Appl. Sci. 2025, 15(15), 8308; https://doi.org/10.3390/app15158308 - 25 Jul 2025
Viewed by 177
Abstract
The research presented in this paper is based on the need for personalized medical implants, whose serial production is impossible, so the need for production process adjustments is inevitable. Conventional production technologies usually set geometrical limitations and generate a lot of waste material, [...] Read more.
The research presented in this paper is based on the need for personalized medical implants, whose serial production is impossible, so the need for production process adjustments is inevitable. Conventional production technologies usually set geometrical limitations and generate a lot of waste material, which leads to great expenses, especially when the material used for production is an expensive Ti alloy. Additive technologies offer the possibility to produce a product almost without waste material and geometrical limitations. Nevertheless, the methods developed for additive production using metal powder are not significantly used in biomedicine because there is insufficient data published regarding the properties of additively produced parts, especially from the fatigue and fracture standpoint. The aim of this research is the experimental determination of fracture mechanics properties of additively produced parts and their comparison with the properties of parts produced by conventional technologies. Drawing is the first production process in the comparison, and the second one is selective laser melting (SLM). The Ti-alloy Ti-6Al-7Nb, used for medical implants, was selected for this research. Experimental testing was performed in order to determine ΔKth fracture mechanics parameters and resistance curves according to ASTM E1820. Test specimen dimensioning and the experiments were carried out according to the respective standards. For the drawn test specimen, the value obtained was ΔKth = 3.84 MPam0.5, and the fracture toughness was Kc = 84 MPam0.5, while for SLM produced test specimens the values were ΔKth = 4.53 MPam0.5, and Kc = 21.9 MPam0.5. Full article
(This article belongs to the Special Issue Application of Fracture Mechanics in Structures)
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18 pages, 3257 KiB  
Article
Experimental Study on the Effects of Loading Rates on the Fracture Mechanical Characteristics of Coal Influenced by Long-Term Immersion in Mine Water
by Xiaobin Li, Gan Feng, Mingli Xiao, Guifeng Wang, Jing Bi, Chunyu Gao and Huaizhong Liu
Appl. Sci. 2025, 15(15), 8222; https://doi.org/10.3390/app15158222 - 24 Jul 2025
Viewed by 235
Abstract
Underground pumped storage hydropower stations (UPSH) are of great significance for energy structure adjustment, and coal mine underground reservoirs are an integral part of UPSH. This study investigates the fracture mechanics behavior of coal in mine water immersion environments with varying loading rates [...] Read more.
Underground pumped storage hydropower stations (UPSH) are of great significance for energy structure adjustment, and coal mine underground reservoirs are an integral part of UPSH. This study investigates the fracture mechanics behavior of coal in mine water immersion environments with varying loading rates and layer direction. Three types of samples were analyzed: Crack-arrester, Crack-splitter, and Crack-divider types. The immersion duration extended up to 120 days. The results indicate that, after immersion in mine water for 120 days, the fracture toughness (KIC), fracture modulus (ES), and absorbed energy (UT) of coal decreased by 60.87%, 53.38%, and 63.21%, respectively, compared to the unsaturated coal samples. An immersion period of 30 days significantly weakens the mechanical properties of coal fractures. The KIC, ES, and UT of coal demonstrate a positive correlation with loading rate, primarily influenced by the duration of coal damage. At the same loading rate, the order of fracture toughness among the three coal types is as follows: Crack-divider > Crack-arrester > Crack-splitter. This hierarchy is determined by the properties of the coal matrix and bedding planes, as well as the mechanical structures composed of them. This study holds significant implications for the safe construction and operational design of underground water reservoirs in coal mines. Full article
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18 pages, 2695 KiB  
Article
Environmentally Sustainable Functionalized WS2 Nanoparticles as Curing Promoters and Interface Modifiers in Epoxy Nanocomposites
by Lyazzat Tastanova, Amirbek Bekeshev, Sultan Nurlybay, Andrey Shcherbakov and Anton Mostovoy
Nanomaterials 2025, 15(15), 1145; https://doi.org/10.3390/nano15151145 - 24 Jul 2025
Viewed by 344
Abstract
This study investigates the effect of the surface functionalization of tungsten disulfide (WS2) nanoparticles with aminoacetic acid (glycine) on the structure, curing behavior, and mechanical performance of epoxy nanocomposites. Aminoacetic acid, as a non-toxic, bio-based modifier, enables a sustainable approach to [...] Read more.
This study investigates the effect of the surface functionalization of tungsten disulfide (WS2) nanoparticles with aminoacetic acid (glycine) on the structure, curing behavior, and mechanical performance of epoxy nanocomposites. Aminoacetic acid, as a non-toxic, bio-based modifier, enables a sustainable approach to producing more efficient nanofillers. Functionalization, as confirmed by FTIR, EDS, and XRD analyses, led to elevated surface polarity and greater chemical affinity between WS2 and the epoxy matrix, thereby promoting uniform nanoparticle dispersion. The strengthened interfacial bonding resulted in a notable decrease in the curing onset temperature—from 51 °C (for pristine WS2) to 43 °C—accompanied by an increase in polymerization enthalpy from 566 J/g to 639 J/g, which reflects more extensive crosslinking. The SEM examination of fracture surfaces revealed tortuous crack paths and localized plastic deformation zones, indicating superior fracture resistance. Mechanical testing showed marked improvements in flexural and tensile strength, modulus, and impact toughness at the optimal WS2 loading of 0.5 phr and a 7.5 wt% aminoacetic acid concentration. The surface-modified WS2 nanoparticles, which perform dual functions, not only reinforce interfacial adhesion and structural uniformity but also accelerate the curing process through chemical interaction with epoxy groups. These findings support the development of high-performance, environmentally sustainable epoxy nanocomposites utilizing amino acid-modified 2D nanofillers. Full article
(This article belongs to the Section Synthesis, Interfaces and Nanostructures)
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15 pages, 7392 KiB  
Article
The Influence of Temperature on the Fracture Toughness and Fracture Mechanism of Ferritic Nodular Cast Iron
by Guobin Duan, Yu Jiang, Yongxin Zhang, Jibin Zhang and Xuechong Ren
Metals 2025, 15(8), 828; https://doi.org/10.3390/met15080828 - 23 Jul 2025
Viewed by 288
Abstract
Nodular Cast Iron (NCI, also known as ductile iron) is widely used in important components such as crankshafts for automotive engines and internal combustion engines, as well as storage and transportation containers for spent fuel in nuclear power plants, due to its good [...] Read more.
Nodular Cast Iron (NCI, also known as ductile iron) is widely used in important components such as crankshafts for automotive engines and internal combustion engines, as well as storage and transportation containers for spent fuel in nuclear power plants, due to its good comprehensive mechanical properties such as strength, toughness, and wear resistance. The effect of temperature on the fracture behavior of NCI was investigated using compact tensile (CT) specimens at different temperatures. The results showed that the conditional fracture toughness parameter (KQ) of the NCI specimens firstly increased and then decreased with decreasing temperature. The crack tip opening displacement δm shows a significant ductile–brittle transition behavior with the decreasing of temperature. δm remains constant in the upper plateau region but sharply decreases in the ductile–brittle region (−60 °C to −100 °C) and stabilizes at a smaller value in the lower plateau region. Multiscale fractographic analysis indicated that the fracture mechanism changed from ductile fracture (above −60 °C) to ductile–brittle mixed (−60 °C to −100 °C) and then to completely brittle fracture (below −100 °C). As the temperature decreased, the fracture characteristics changed from ductile dimples to dimple and cleavage mixed and then to brittle cleavage. Full article
(This article belongs to the Special Issue Fracture and Fatigue of Advanced Metallic Materials)
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22 pages, 10555 KiB  
Article
Mechanical Properties and Cutting Performance of Si3N4/Sc2W3O12 Composite Ceramic Tools Materials
by Zhiyuan Zhang, Xiaolan Bai, Jingjie Zhang, Mingdong Yi, Guangchun Xiao, Tingting Zhou, Hui Chen, Zhaoqiang Chen and Chonghai Xu
Materials 2025, 18(15), 3440; https://doi.org/10.3390/ma18153440 - 22 Jul 2025
Viewed by 395
Abstract
To address the poor thermal shock resistance and high brittleness of traditional ceramic tools, a novel Si3N4/Sc2W3O12 (SNS) composite ceramic material was developed via in situ synthesis using WO3 and Sc2O [...] Read more.
To address the poor thermal shock resistance and high brittleness of traditional ceramic tools, a novel Si3N4/Sc2W3O12 (SNS) composite ceramic material was developed via in situ synthesis using WO3 and Sc2O3 as precursors and consolidated by spark plasma sintering. Sc2W3O12 with negative thermal expansion was introduced to compensate for matrix shrinkage and modulate interfacial stress. The effects of varying Sc2W3O12 content on thermal expansion, residual stress, microstructure, and mechanical properties were systematically investigated. Among the compositions, SNS3 (12 wt.% Sc2W3O12) exhibited the best overall performance: relative density of 98.8 ± 0.2%, flexural strength of 712.4 ± 30 MPa, fracture toughness of 7.5 ± 0.3 MPa·m1/2, Vickers hardness of 16.3 ± 0.3 GPa, and an average thermal expansion coefficient of 2.81 × 10−6·K−1. The formation of a spherical chain-like Sc-W-O phase at the grain boundaries created a “hard core–soft shell” interface that enhanced crack resistance and stress buffering. Cutting tests showed that the SNS3 tool reduced workpiece surface roughness by 32.91% and achieved a cutting distance of 9500 m. These results validate the potential of this novel multiphase ceramic system as a promising candidate for high-performance and thermally stable ceramic cutting tools. Full article
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29 pages, 8058 KiB  
Article
Hydrogen Embrittlement Behavior and Applicability of X52 Steel in Pure Hydrogen Pipelines
by Tianlei Li, Honglin Zhang, Wentao Hu, Ke Li, Yaxi Wang and Yuanhua Lin
Materials 2025, 18(14), 3417; https://doi.org/10.3390/ma18143417 - 21 Jul 2025
Viewed by 245
Abstract
This study investigates the mechanical behavior of X52 steel pipes and their weld regions under pure hydrogen transport conditions, with a focus on assessing potential hydrogen embrittlement risks. Through experimental analysis, the research evaluates how different pipeline regions—including the base metal, weld metal, [...] Read more.
This study investigates the mechanical behavior of X52 steel pipes and their weld regions under pure hydrogen transport conditions, with a focus on assessing potential hydrogen embrittlement risks. Through experimental analysis, the research evaluates how different pipeline regions—including the base metal, weld metal, and heat-affected zones—respond to varying hydrogen pressures. Key mechanical properties such as elongation, fracture toughness, and crack growth resistance are analyzed to determine their implications for structural integrity and safety. Based on the findings, this study proposes criteria for the safety evaluation of X52 pipelines operating in hydrogen service environments. The results are intended to inform decisions regarding the repurposing of existing pipelines or the design of new infrastructure dedicated to pure hydrogen transport, offering insights into material performance and critical safety considerations for hydrogen pipeline applications. Full article
(This article belongs to the Section Mechanics of Materials)
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17 pages, 2862 KiB  
Article
Crack Assessment Using Acoustic Emission in Cement-Free High-Performance Concrete Under Mechanical Stress
by Muhammad Ali Rostampour, Davood Mostofinejad, Hadi Bahmani and Hasan Mostafaei
J. Compos. Sci. 2025, 9(7), 380; https://doi.org/10.3390/jcs9070380 - 19 Jul 2025
Cited by 1 | Viewed by 332
Abstract
This study investigates the cracking behavior of high-performance calcium oxide-activated concrete incorporating basalt and synthetic macro fibers under compressive and flexural loading. Acoustic emission (AE) monitoring was employed to capture real-time crack initiation and propagation, offering insights into damage evolution mechanisms. A comprehensive [...] Read more.
This study investigates the cracking behavior of high-performance calcium oxide-activated concrete incorporating basalt and synthetic macro fibers under compressive and flexural loading. Acoustic emission (AE) monitoring was employed to capture real-time crack initiation and propagation, offering insights into damage evolution mechanisms. A comprehensive series of uniaxial compression and four-point bending tests were conducted on fiber-reinforced and plain specimens. AE parameters, including count, duration, risetime, amplitude, and signal energy, were analyzed to quantify crack intensity and classify fracture modes. The results showed that tensile cracking dominated even under compressive loading due to lateral stresses, while fiber inclusion significantly enhanced toughness by promoting distributed microcracking and reducing abrupt energy release. Basalt fibers were particularly effective under flexural loading, increasing the post-peak load-bearing capacity, whereas synthetic macro fibers excelled in minimizing tensile crack occurrence under compression. Full article
(This article belongs to the Section Composites Applications)
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23 pages, 7058 KiB  
Article
Experimental Investigation of Steel Bar Corrosion in Recycled Plastic Aggregate Concrete Exposed to Calcium Chloride Cycles
by Federica Zanotto, Alice Sirico, Andrea Balbo, Patrizia Bernardi, Sebastiano Merchiori, Vincenzo Grassi, Beatrice Belletti and Cecilia Monticelli
Materials 2025, 18(14), 3361; https://doi.org/10.3390/ma18143361 - 17 Jul 2025
Viewed by 210
Abstract
Recycling plastics waste into concrete represents one of the possible approaches for its valorization, offering both economic and environmental benefits. Although numerous studies have explored the mechanical properties of concrete with plastics waste, its durability performance remains largely unexplored. In this context, this [...] Read more.
Recycling plastics waste into concrete represents one of the possible approaches for its valorization, offering both economic and environmental benefits. Although numerous studies have explored the mechanical properties of concrete with plastics waste, its durability performance remains largely unexplored. In this context, this study aims to assess the electrochemical behavior of rebars embedded in reinforced concrete modified by partially replacing natural aggregates with recycled plastics, comparing their behavior to that of conventional concrete. The corrosion of reinforcing steel bars was evaluated by wet and dry cycles (w/d) in calcium chloride solutions, monitoring corrosion potential and potentiostatic polarization resistance, and recording electrochemical impedance spectroscopy (EIS) and polarization curves. In addition, the chloride diffusion tendency and the mechanical performances were assessed in unreinforced samples. The findings indicate that in environments with lower chloride concentrations, concrete with plastic granules provides good protection against rebar corrosion. Although the mechanical results of the studied mixes confirmed that incorporating plastic granules as aggregates in the concrete matrix causes a reduction in compressive strength, as known in the literature, the modified concrete also exhibits improved post-cracking behavior, resulting in enhanced ductility and fracture toughness. Full article
(This article belongs to the Section Construction and Building Materials)
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19 pages, 1914 KiB  
Article
Fracture Behavior Assessment of Rubberized Concrete Using Non-Standard Specimens: Experimental Investigation and Model Optimization
by Shuang Gao, Zhenyu Wang, Jiayi Sun, Juan Wang, Yu Hu and Hongyin Xu
Technologies 2025, 13(7), 307; https://doi.org/10.3390/technologies13070307 - 17 Jul 2025
Viewed by 249
Abstract
With the advancement of modern engineering structures, traditional cement concrete is increasingly unable to meet the mechanical performance requirements under complex conditions. To overcome the performance limitations of materials, modified concrete has become a focal point of research. By incorporating modifying materials such [...] Read more.
With the advancement of modern engineering structures, traditional cement concrete is increasingly unable to meet the mechanical performance requirements under complex conditions. To overcome the performance limitations of materials, modified concrete has become a focal point of research. By incorporating modifying materials such as fibers, polymers, or mineral admixtures, the properties of concrete can be significantly enhanced. Among these, rubberized concrete has attracted considerable attention due to its unique performance advantages. This study conducted fracture tests on rubberized concrete using non-standard concrete three-point bending beam specimens of varying dimensions to evaluate its fracture performance. Employing conventional concrete fracture theoretical models, the fracture toughness parameters of rubberized concrete were calculated, and a comparative analysis was performed regarding the applicability of various theoretical calculation formulas to rubberized concrete. The results indicated that the fracture performance of rubberized concrete varied significantly with changes in specimen size. The initial toughness exhibited a consistent size-dependent variation across different theoretical models. The fracture toughness corresponding to crack height ratios between 0.05 and 0.25 showed contradictory trends; however, for crack height ratios between 0.3 and 0.5, the fracture toughness became consistent. This study integrated boundary effect theory and employed Guinea’s theory to propose an optimization coefficient γ for the double-K fracture toughness formula, yielding favorable optimization results. Full article
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