The need for non-toxic radiation-shielding composites has increased because conventional lead-based and heavyweight shielding solutions raise environmental, handling and structural-load concerns. This study aimed to evaluate whether thermally treated colemanite, a naturally occurring boron-rich mineral, can improve photon and neutron attenuation in a cement-based matrix while clarifying the associated mechanical penalty. Portland-cement composites containing 0, 1, 5 and 10 wt.% colemanite were prepared and tested for X-ray/gamma-ray mass attenuation, neutron attenuation, 7-day compressive strength, SEM morphology and XRD phase identification. Colemanite addition modified photon attenuation in an energy-dependent manner, with the strongest average low-energy improvement observed for the 5 wt.% mixture (+5.5% relative to the control). The effective linear neutron attenuation coefficient increased from 0.248 cm -1 for the control to 0.346 cm -1 for the 5 wt.% composite, whereas the highest density-normalized neutron attenuation value was obtained at 10 wt.% colemanite. This shielding benefit was accompanied by severe strength loss: 29.3%, 93.0% and 98.0% at 1, 5 and 10 wt.% colemanite, respectively. SEM and XRD findings indicate that colemanite was incorporated as a crystalline particulate phase, but heterogeneous dispersion and hydration interference governed the shielding-mechanical trade-off. The composites are therefore more suitable for non-load-bearing radiation-protective panels, partitions and surface layers than structural concrete applications.
Continuous-reinforced thermoplastic composites are becoming increasingly important for mass production of lightweight components across various industrial sectors. This paper describes a novel process chain for the production of continuous fibre reinforced thermoplastic matrices with a rotationally symmetric cross-section, using rotational moulding technology. The process chain is based on wound and pre-consolidated preforms, which are then formed into the final geometry by rotational moulding. To support the manufacturing of smaller diameters, a composite core is used to increase the pressure during manufacture. The experimental results are examined by cross-sectional micrographs and show the approach’s feasibility.
This study investigates the mechanical properties of carbon fiber-reinforced epoxy composites reinforced with recycled textiles from the automotive industry-specifically airbag fabric (nylon 6.6) and seat-belt webbing (polyester). The objective was to assess the potential of these recycled reinforcements to enhance impact resistance, which is critical for automotive safety applications. Six composite configurations with different lay-ups were manufactured: a reference carbon composite (C), a carbon composite reinforced with a conventional aramid fabric (A), and four hybrid composites incorporating nylon 6.6 (AB), seat-belt webbing (P), an aramid/seat-belt combination (AP), and a nylon 6.6/seat-belt combination (PB). Specimens were produced by hand lay-up and subsequently subjected to mechanical testing. Tensile properties were evaluated in accordance with & Ccaron;SN EN ISO 527-4, and Charpy impact performance was measured according to ISO 179-2 (unnotched). The results showed that incorporating recycled seat-belt reinforcement (P, AP, PB) led to a pronounced increase in impact strength (most notably for AP) compared with the reference carbon composite (C). However, this improvement in toughness was accompanied by a reduction in tensile strength. The aramid-only configuration (A) achieved the highest average tensile strength. The hybrid AP and PB laminates, combining carbon plies with aramid fabric/nylon 6.6 and seat-belt reinforcement, exhibited the best impact energy absorption capability. Overall, the findings suggest that recycled seat-belt textiles represent a promising alternative reinforcement for improving the toughness of carbon composites in applications requiring high impact resistance, provided that the trade-off between toughness and static strength is carefully considered.
This article investigates the feasibility of manufacturing a biocomposite composed of a biopolymer, poly (beta-hydroxybutyrate-co-beta-hydroxyvalerate) (PHBV), reinforced with cellulose nonwoven Alfa fibers. To better understand the behavior of this composite, accelerated weathering tests were conducted. To simulate extreme environmental conditions, composite samples were exposed to cyclic ultraviolet (UV) light, water spray, heat, and high relative humidity. The tensile and physical properties (mass and cross-sectional dimensions) of the composites were evaluated throughout the aging process. Changes in elastic modulus, stress, strain, as well as mass, width, and thickness were recorded. The study revealed the effects of accelerated weathering on PHBV-Alfa composites. Overall, the samples exhibited a relative decrease in physical and mechanical properties, except for the elastic modulus, which showed a slight increase toward the end of the test. Furthermore, the main degradation mechanisms responsible for the observed property reductions were identified as photolysis, hydrolysis, and photooxidation of the polymer surface, along with fiber-matrix interface deterioration caused by swelling of Alfa cellulosic fibers.
The goal of this article was to integrate finite element analysis (FEA), multi-layer perception (MLP) and transfer learning based convolutional neural network (CNN) for predicting stiffness and strength of woven carbon-glass/epoxy pseudo ductile hybrid composites (PDHCs). To minimize the cost of experimental campaigns, research trends have shifted toward optimizing flight range, speed and battery capacity optimization of electric vertical take-off and landing (eVTOL) structure, as well as utilization of computational frameworks in mechanical property prediction and crashworthiness analysis. However, due to complex failure mechanisms of composites, it was very challenging to predict mechanical properties of PDHCs using conventional FEA. As such, it was very essential to train accurate machine learning model to reduce the hassle of computationally intensive FEA. The CNN model was trained using FEA geometric image dataset, achieving an accuracy of 89.77% and 90.91% sensitivity. The MLP model was trained to map CNN predicted images to detailed numerical outcomes demonstrating excellent convergence with validation and training losses of 0.060 and 0.062, respectively, using a 15-layer architecture with swish activation and regularization. The pseudo-ductile hybrid material developed had showed better performance with large plastic deformation resembling ductile materials. The stress strain response was dominated by carbon plies in linear elastic zone followed by gradual fragmentation, matrix cracking, fiber pull out and debonding with the outer glass plies arresting crack. The numerical comparison of FEM predictions were closely matched with the experimental data in the literature with absolute error less than 5% for tensile strength, tensile modulus, flexural strength and impact strength. The proposed approach gives an insight to overcome the limitations of conventional models for woven hybrids, enabling optimized PDHC design for electric vertical take-off and landing aircraft (eVTOL) applications.
This study examines the particle size-dependent effects of basalt powder as a supplementary cementitious material and develops a predictive model linking fineness to concrete strength. Four basalt powders (400, 800, 1600, and 2400 mesh) replaced slag at a constant dosage and water-binder ratio. Compressive strength was measured at 3, 7, 28, and 90 days, and XRD, TG-DTG, MIP, and SEM were used to investigate hydration, Ca(OH)2 consumption, pore structure, and microstructure. The results show that finer basalt powder enhances both early and long-term strength. Coarse basalt powder mainly contributes through micro-filler effects, while ultrafine basalt promotes additional C-(A)-S-H formation through both micro-filling and pozzolanic reactions, significantly reducing porosity. A strong inverse linear relationship between D90 and compressive strength at 28 and 90 days is established, offering a reliable tool for performance prediction. This work provides insights into the structure-property relationship of basalt powder fineness and introduces a particle-size-based design framework for high-performance, low-carbon concrete.
This study examines how aluminum oxide (Al2O3) powder in micrometer (& micro;m) affects the mechanical characteristics, microstructural characteristics, and slurry erosion resistance of high-density polyethylene (HDPE) composites manufactured via pipe extrusion. Al2O3 particles with an average size of 5 & micro;m were added to the HDPE matrix at weight percentages of 0.5 wt.%, 0.7 wt.%, and 1 wt.%. Scanning electron microscopy (SEM) was used to analyze the compound morphology, and tensile properties and resisting erosion were assessed in accordance with ASTM recommendations. The results show that the properties of HDPE composites are dramatically changed by the addition of Al2O3. The composite with 0.5 wt.% Al2O3 had the most stable particles dispersion and strong interfacial bonding when contrasted with unfilled HDPE, resulting in a about 13% increase in tensile strength. Tensile strength decreased but material stiffness increased due to particle agglomeration brought on by an increase in filler content. The composite with 1 wt.% Al2O3 demonstrated a 51% reduction in erosion rate when compared to pure HDPE. Erosion resistance gradually improved with higher Al2O3 loadings, according to slurry erosion tests. In essence, the study demonstrates that there is a trade-off between enhancing erosion resistance and optimizing mechanical properties, depending on the filler content. These findings provide valuable insights into the erosion behavior of extruded HDPE/Al2O3 composite pipes and demonstrate their suitability for fluid transport and sanitary applications that demand greater durability in erosive environment.
This study explores the development, experimental evaluation, and optimization of a hybrid jute/PET fiber-reinforced polyester composite for lightweight automotive applications, particularly bus roof panels. 10 laminates were prepared by varying the weight fractions of Jute and PET fibers and their stacking sequences. These laminates were grouped into four categories: (1) pure Jute/Polyester laminates, (2) hybrid Jute-PET configurations with alternating layers of Jute and PET (J-P-J-P), (3) hybrid configurations with a PET-dominated outer layer (P-J-J-P), and (4) hybrid configurations with a Jute-dominated outer layer (J-P-P-J). The weight fractions of Jute and PET fibers ranged from 10% to 40%, with the remaining content being polyester resin. Mechanical testing, including tensile, compressive, flexural, and impact tests, showed that hybridizing with PET slightly reduced tensile and compressive strengths but significantly improved flexural strength, impact resistance, and reduced water absorption. The stacking sequence influenced performance, with the P-J-J-P configuration identified as optimal through the TOPSIS multi-criteria decision-making method. Optimization using HyperWorks-OptiStruct resulted in a 34.58% mass reduction in the bus roof panel, leading to an estimated fuel saving of 0.146 L per 100 km. Finite element analysis (FEA) with Abaqus validated the results, showing minimal displacement (3.88 mm) and a safety factor aligned with failure criteria. These findings demonstrate the potential of hybrid Jute/PET composites as a sustainable, high-performance alternative to steel in automotive applications.
Magnesium silicofluoride (MgSiF6), a byproduct of phosphate fertilizer production, serves as an effective retarder of sulfoaluminate cementitious grouting materials (SAGMs). The incorporation of triethanolamine (TEA) at concentrations ranging from 0.15 to 0.85 g/L results in a reduction of the slurry’s setting time and an increase in its compressive strength. Conversely, when the concentration is increased to 1.5–8.5 g/L, a decline in compressive strength is observed. The underlying mechanism for this phenomenon requires further investigation. The results show that when the concentration of MgSiF 6 is 1.5 g/L, a TEA concentration of 0.15–8.5 g/L promotes the dissolution of CaSO 4 and C 4 A 3 S ¯ . The promoting effect on the dissolution of CaSO 4 increases with the increase in TEA concentration, while the promoting effect on the dissolution of C 4 A 3 S ¯ initially shows an increasing trend and then decreases. In the presence of MgSiF 6 , TEA promoted the formation of ettringite at low concentrations (0.15 and 0.85 g/L) and inhibiting its formation at high concentrations (1.5 and 8.5 g/L). All concentrations of TEA encourage the formation of aluminum hydroxide, but at 0.85 g/L concentration, the size of the ettringite and aluminum hydroxide generated is smaller, affecting the pore structure and resulting in higher compressive strength.
This study presents a comprehensive evaluation of hybrid composites made from high-density polyethylene (HDPE), calcium carbonate (CaCO3), and palm kernel shell (PKS) particles, focusing on their thermal, mechanical, and moisture-resistance properties. PKS, a lignocellulosic agro-waste, was pretreated with NaOH and incorporated at varying loadings (10-25 wt%) and particle sizes (125 mu m and 500 mu m); CaCO3 content was adjusted so that the total filler loading remained 30 wt%. Fourier-transform infrared spectroscopy (FTIR) confirmed chemical interactions and surface modification of PKS after treatment. Differential Scanning Calorimetry (DSC) revealed minimal variation in melting temperature across formulations but showed distinct changes in enthalpy of fusion and degree of crystallinity, particularly with increasing PKS content. Thermogravimetric analysis (TGA) and derivative thermogravimetry (DTG) indicated enhanced thermal stability for CaCO3-rich composites, while PKS-rich formulations showed earlier onset of thermal degradation due to lignocellulosic decomposition. Water absorption results demonstrated that both filler content and particle size significantly influence hydrophilicity, with smaller particles exhibiting reduced water uptake because of better dispersion and packing. Mechanical testing showed that composites with 10 wt% PKS (especially at 125 mu m) exhibited superior ultimate tensile strength and impact energy, balancing reinforcement and toughness. Higher PKS contents led to agglomeration, reduced ductility, and diminished strength. Hardness generally increased with filler content and was more pronounced in composites containing larger PKS particles. The results highlight the potential of PKS/CaCO3/HDPE hybrids as sustainable, high-performance materials for engineering applications, with optimal performance achieved at 10-15 wt% PKS using fine particles.
In recent years, bio-based epoxy has gained significant attention for use in fiber-reinforced composite materials and structures, particularly in the aerospace industry, which is increasingly focused on sustainability. Consequently, it is crucial to study bio-based epoxies, perform material characterization, and compare their behavior with conventional epoxies. This study aims to determine the effect of moisture on the mechanical properties of three bio-based epoxies: two non-recyclable and one recyclable. Four different types of tests were conducted, namely, tensile, compression, bending, and fracture toughness tests. The results indicate that the recyclable bio-epoxy exhibits lower moisture absorption at 2.3% compared to the non-recyclable bio-epoxy. Recyclable bio-epoxy shows excellent fracture toughness, which is the main criteria for a resin when it is used as a composite matrix in aerospace, with a fracture toughness KIC of 2.5 MPa.m0.5. This result suggests its high potential as a viable alternative in aerospace.
This paper investigates the adhesive bonding strength of steel-carbon fiber reinforced composites and their simulation analysis method, validating the approach on an automotive hybrid B-pillar to provide a basis for reliable joining of dissimilar materials. By combining adhesive bonding mechanics theory, the material property parameters of DC04 steel and carbon fiber reinforced polymer (CFRP) substrates are determined, offering parameters for finite element modeling of dissimilar material adhesive bonding. Lap shear and butt tensile tests are designed for the adhesive-bonded joints of DC04 steel and CFRP, enabling determination of main mechanical properties of Araldite 2015 structural adhesive and its adhesive performance. A finite element model of the DC04 steel-CFRP adhesive-bonded joint is built to simulate maximum load and failure displacement of the joint, analyze adhesive bonding strength, and compare results with test data. Scanning electron microscopy (SEM) is employed to analyze failure modes of the adhesive joints. A simulation analysis method for adhesive bonding of DC04 steel-CFRP dissimilar materials is established. Adhesive bonding simulations are performed on the automotive steel-CFRP hybrid B-pillar. Based on performance requirements of the B-pillar, simulations are conducted for axial tension, axial compression, lateral bending, and rearward bending, calculating deformation and stress parameters of the adhesive bonding elements under each condition. The carbon fiber composite B-pillar reinforcement plate is manufactured and bonded to the steel outer panel using Araldite 2015 adhesive. A three-point bending test was conducted on the hybrid material B-pillar assembly. Simulation values for displacement and stress are compared with test results, with maximum errors of 2.94% and 3%, respectively. The results validate accuracy and correctness of the adhesive bonding simulation for the dissimilar material B-pillar assembly and demonstrate feasibility and reliability of the proposed adhesive bonding simulation method and strength analysis for the steel and CFRP dissimilar material combination.
The increasing demand for sustainable materials has driven the development of hybrid composites to improve mechanical properties while reducing environmental impact. This study investigates the notch insensitivity and strain distribution behaviour of three hybrid composites: carbon fibre/recycled carbon fibre (CF/rCF), glass fibre/recycled carbon fibre (GF/rCF), and flax fibre/recycled carbon fibre (FF/rCF). Digital Image Correlation (DIC) analysis was employed to examine strain distribution and crack initiation across different loading conditions for both hybrid and non-hybrid composites. Results indicate that the CF/rCF and GF/rCF hybrids improved notch insensitivity and resistance to crack propagation compared to pure CF and GF composites, with rCF contributing to stress distribution and delaying crack initiation. Conversely, the FF/rCF hybrid displayed higher strain concentrations around notches than pure flax fibre, suggesting that hybridization with rCF may not provide the same benefits for natural fibres. These findings highlight the potential of hybrid composites for applications that require both durability, sustainability, and underscore the influence of fibre type on the effectiveness of hybridization. This research advances our understanding of the mechanical performance of sustainable hybrid composites and provides a foundation for the development of optimized materials for eco-friendly applications. These materials show promise for use in automotive, marine, and secondary aerospace structures where sustainable, damage-tolerant composites are needed.
This study investigates the development of lightweight, hybrid reinforced epoxy composites using chicken feather fiber (CFF) and glass fiber (GF) as reinforcements for automotive applications. The composites were fabricated by combining treated chicken feather fibers and glass fibers in a 1:1 wt ratio within an epoxy matrix. The mechanical, thermal, and abrasion properties of the composites were assessed through tensile, flexural, hardness, impact, and wear tests, alongside thermal conductivity measurements. The results revealed that the tensile strength (62.49 MPa) and modulus (801.28 MPa) peaked at 12 wt% reinforcement, with increases of 54% and 36%, respectively, compared to the unreinforced epoxy. The composite with 9 wt% hybrid reinforcement exhibited the highest flexural strength (119.37 MPa), while the 12 wt% hybrid composites showed the best impact resistance (27.9 J/mm2). The wear resistance showed that all the reinforced composites had improved wear resistance, with 18 wt% having the highest wear resistance of 0.12 mg. Additionally, the reinforced composites demonstrated lower thermal conductivity with increasing fiber content as compared with the unreinforced composite, with 12 wt% reinforcement having the lowest thermal conductivity value of 0.000018 W/mK. SEM analysis revealed a strong interfacial bonding between the fibers and the matrix, contributing to the composites' improved mechanical and thermal properties. The successful hybridization of chicken feathers and glass fibers offers a promising sustainable approach for structural and environmental applications such as automotive components, providing lightweight materials with improved performance, cost-effectiveness, and environmental benefits over traditional materials.
Magnesium silicofluoride (MgSiF6), a byproduct of phosphate fertilizer production, serves as an effective retarder of sulfoaluminate cementitious grouting materials (SAGMs). The incorporation of triethanolamine (TEA) at concentrations ranging from 0.15 to 0.85 g/L results in a reduction of the slurry's setting time and an increase in its compressive strength. Conversely, when the concentration is increased to 1.5-8.5 g/L, a decline in compressive strength is observed. The underlying mechanism for this phenomenon requires further investigation. The results show that when the concentration of MgSiF6 is 1.5 g/L, a TEA concentration of 0.15-8.5 g/L promotes the dissolution of CaSO4 and C4A3S. The promoting effect on the dissolution of CaSO4 increases with the increase in TEA concentration, while the promoting effect on the dissolution of C4A3S initially shows an increasing trend and then decreases. In the presence of MgSiF6, TEA promoted the formation of ettringite at low concentrations (0.15 and 0.85 g/L) and inhibiting its formation at high concentrations (1.5 and 8.5 g/L). All concentrations of TEA encourage the formation of aluminum hydroxide, but at 0.85 g/L concentration, the size of the ettringite and aluminum hydroxide generated is smaller, affecting the pore structure and resulting in higher compressive strength.
The aim of this study is to evaluate the effects of the water-to-binder ratio and water-to-sand ratio on the structural properties of high-strength lightweight concrete. To this end, the tested properties included slump, water absorption, density, compressive strength, flexural strength, splitting tensile strength, and modulus of elasticity. Finally, the microscopic features of the concrete were observed by scanning electron microscopy (SEM). The results demonstrated that the compressive strength, flexural strength, splitting tensile strength, modulus of elasticity, and high-strength lightweight concrete exhibited inverse relationships with increasing water-to-binder ratios and water-to-sand ratios. In addition, the splitting tensile strength exhibited a more pronounced sensitivity to changes in the aforementioned ratios than did the compressive strength. Microscopic analysis revealed that the incorporation of lightweight aggregate enhanced the mechanical properties at room temperature, conferring both lightweight and high-strength characteristics to the resulting material. Furthermore, on the basis of the aforementioned results, this study presents an effective method for predicting the strengths from water-sand ratios (w/b and w/s). Additionally, the compressive strength can be optimized through the development of equations. The results of this research have the potential to facilitate the practical implementation of concrete in real-world pavement projects. In other words, the use of oil shale aggregate and clean recycled concrete aggregate for bridge decks resulted in savings of 368 tons of structural steel, 363 tons of suspension and cable, 2060 tons of bridge deck weight, and cost savings of US$320,000 in the pier-pier portion of the bridge.
This study uses functionally graded material (FGM) consisting of aluminum (Al) and iron (Fe) produced by powder metallurgy method with different microstructures. Al and Fe powders are prepared, mixed at different ratios for each step, and compressed by the hot pressing method to obtain FGM. The four layer FGM composite was fabricated by employing powder metallurgy method. The layers were stacked with a surface of Al and Fe 80–20 wt% on top (1st layer) with succeeding layers of Al and Fe at (60–40 wt% (2nd layer), 40–60 wt% (3rd layer), and 20–80 wt% (4th layer)). The distributions at interfaces between the stages are characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). Obtained data indicate that Al and Fe are homogeneously distributed in the structure in all grades. Increasing the Fe ratio in the layers creates porosity in the Al phase. A Scherrer–Warren equation calculates grain sizes and the lattice parameters in XRD analyses. Vickers indentation is used to determine the hardness of the stages and interstages of the FGM. It is shown that the microstructural and mechanical properties of FGM composites increase by increasing Fe material composition. The results of 4th grade (20% Al + 80% Fe) composite showed improved interface layer microstructure and a maximum hardness of 105.75 HV for grades and 97 HV for interfaces of the FGM composite.
This study proposes a new rapid measurement method for determining the Weibull parameters of carbon fiber strength distribution based on tensile testing of carbon fiber bundles. Unlike traditional fiber bundle tests, which require both stress and strain measurements, this method only requires testing the tensile strength of the fiber bundles. The process involves three key steps: First, a formula derived from the Weibull distribution function was used to establish the relationship between the Weibull parameters and the tensile strength of fiber bundles of different lengths. Next, fiber bundles of varying lengths were selected for tensile strength testing. Finally, the Weibull parameters were calculated by substituting the test results into the formula. This method offers several advantages: First, compared to single fiber testing, this method eliminates the need to test a large number of individual fiber strength values, requiring only a few bundles of different lengths to be tested. The experimental equipment is both reliable and affordable. Second, unlike the traditional fiber bundle test, which involves testing both tensile strength and the F ∼ ε (or σ ∼ ε ) curve (including strain measurements), this method focuses solely on tensile strength. As a result, the testing equipment is simpler to operate, and time costs are reduced. Third, the data processing is straightforward, requiring only a few data points to be inputted into the formula. The Weibull parameters of fiber strength obtained through this method have been validated by multiple experiments conducted on fiber bundles of different lengths, confirming its accuracy and reliability.
Fibre-reinforced composites, such as carbon fibre-reinforced polymers (CFRP) and glass fibre-reinforced polymers (GFRP), are widely utilized in engineering applications for their exceptional strength and stiffness. However, their brittle failure and limited impact resistance hinder broader applications, especially in high-impact environments. Improving impact resistance is therefore critical for advancing their performance and expanding their usability. This study explores the development of novel composites with components hybridized on microscale that integrate high-strength fibres (e.g., carbon, glass) with ductile fibres (e.g., steel, aramid) through the fabrication of hybrid yarns featuring highly dispersed fibre components, rather than conventional layer-wise configurations. Three distinct hybrid composite concepts were developed using innovative fibre combinations and manufacturing techniques: Concept 1 (carbon, aramid, and thermoplastic filament yarns), Concept 2 (glass, stainless steel, and polypropylene yarns), and Concept 3 (recycled aramid, carbon, and thermoplastic fibres). The experimental results (tensile and Charpy impact tests) show that by using a specific combination of fibre materials, the properties: tensile strength, impact strength, and energy absorption of the hybrid composite can be specifically modified to meet the needs of the application. Notably, Concept 1 exhibited the highest tensile strength, while Concept 2 excelled in ductility and energy absorption. The hybrid yarns, produced using air texturing and carding techniques, showed optimized tensile properties through fine-tuning of air pressure and overfeed rates during manufacturing. These findings underscore the potential of hybrid composites with highly dispersed components in engineering applications requiring tailored properties.
This study aims to evaluate the effects of basalt fibers on the triaxial compressive permeability and shear performance of concrete after exposure to high temperatures under different cooling methods. The triaxial compressive strength, permeability, and shear performance of ordinary concrete (OC) and basalt fiber-reinforced concrete (BFRC) were investigated. The results indicate that the incorporation of basalt fibers significantly improves the density and compressive strength of concrete, with the most pronounced enhancement observed at a 1.0% volume fraction. After high-temperature exposure, the mass loss rates of both OC and BFRC increased with rising temperatures, while the relative dynamic elastic modulus gradually decreased. Performance degradation was more pronounced under water cooling conditions compared to natural cooling conditions. The addition of basalt fibers effectively reduced the mass loss rate and improved the relative dynamic elastic modulus. In triaxial compression tests, natural cooling was more effective than water cooling at maintaining the strength and toughness of concrete. During water cooling, the thermal shock effect resulted in increased internal cracking, thereby significantly increasing the permeability. However, the addition of basalt fibers effectively reduced the porosity of concrete, thus enhancing its impermeability. Furthermore, in variable-angle shear tests, basalt fibers significantly improved the shear performance and toughness of concrete, particularly under water cooling conditions. The findings of this study provide theoretical and practical references for the application of basalt fiber-reinforced concrete in high-temperature environments.
