Basalt Fiber Research Articles

Mechanical properties and acoustic emission characteristics of basalt fiber reinforced cemented silty sand subjected to freeze–thaw cycles

Freeze–thaw (F–T) cycling poses a significant challenge in seasonally frozen zones, notably affecting the mechanical properties of soil, which is a critical consideration in subgrade engineering. Consequently, a series of unconfined compressive strength tests were conducted to evaluate the influence of various factors, including fiber content, fiber length, curing time, and F–T cycles on the unconfined compression strength (UCS) of fiber-reinforced cemented silty sand. In parallel, acoustic emission (AE) testing was conducted to assess the AE characteristic parameters (e.g., cumulative ring count, cumulative energy, energy, amplitude, RA, and AF) of the same material under F–T cycles, elucidating the progression of F–T-induced damage. The findings indicated that UCS initially increased and then declined as fiber content increased, with the optimal fiber content identified at 0.2%. UCS increased with prolonged curing time, while increases in fiber length and F–T cycles led to a reduction in UCS, which then stabilized after 6 to 10 cycles. Stable F–T cycles resulted in a strength loss of approximately 30% in fiber-reinforced cemented silty sand. Furthermore, AE characteristic parameters strongly correlated with the stages of damage. F–T damage was segmented into three stages using cumulative ring count and cumulative energy. An increase in cumulative ring count to 0.02 × 104 times and cumulative energy to 0.03 × 104 mv·μs marked the emergence of critical failure points. A sudden shift in AE amplitude indicated a transition in the damage stage, with an amplitude of 67 dB after 6 F–T cycles serving as an early warning of impending failure.

IMPACT OF HOLLOW CORE DIAMETER AND BFRP WRAPPING ON AXIAL COMPRESSIVE STATIC PERFORMANCE OF TIMBER

This paper presents an experimental study on the axial compressive static performance of the cylindrical timber-wrapped basalt fiber reinforced polymer (BFRP). Beech and black pine woods were used as cylindrical timber material, polyurethane (PUR) adhesive was used as the adhesive agent, and BFRP was used as fiber-reinforced polymers (FRP). The stress on compression tests was applied to 70 pieces of test samples prepared. The results showed that there was found out that the highest average stress value of 51.8 MPa was achieved inthe black pine cylindrical timber- BFRP wrapping- hollow core (Ø=70 mm)- the beech cylindrical timber blocks- BFRP wrapping samples under compression loading. The lowest average value stress value of 30.78 MPa was found in the black pine cylindrical timber- none hollow core samples. On average, the stress of the black pine cylindrical timber- BFRP wrapping- hollow core (Ø=70 mm)- the beech cylindrical timber blocks- BFRP wrapping samples were68% higher than the stress of the black pine cylindrical timber- none hollow core samples. The influence of the hollow core diameter and the BFRP wrapping type were found statistically significant.

Flexural and interlaminar shear response of novel methylmethacrylate composites reinforced with high-performance fibres

This experimental work presents a comparative study on the mechanical behaviour of novel infusible methylmethacrylate matrix (Elium®) composites reinforced with different types of high-performance fibres. A vacuum-assisted resin infusion process was employed to fabricate the laminates using carbon, basalt, Kevlar®, and high molecular weight polyethene (UHMWPE) fibres. Flexural and interlaminar shear properties of the composites were evaluated. Test results revealed that carbon fibre composites had superior flexural strength, stiffness and interlaminar shear stress as compared to the other composites tested. Further, composites containing Kevlar and UHMWPE fibres demonstrated significantly higher flexural strains to failure. Post-testing, specimens were examined using scanning electron microscopy (SEM). Microscopy revealed possible interfacial interaction differences based on the reinforcement fibre type, which was further confirmed by an analytical approach for analysing the flexural behaviour of various types of composites. The sequence of damage progression in specimens was also analysed.

Experimental study and model evaluation on BFRP tube-confined RAC cylinders under monotonic axial compression

Using concrete waste as recycled aggregate (RA) in engineering structures can generate great ecological and economic benefits. To enhance the compressive properties of RA concrete (RAC), basalt fiber reinforced polymer (BFRP) tubes were used to provide lateral confinement in this study. Monotonic axial compressive tests were carried out on BFRP tube-confined RAC using 36 cylindrical specimens. Detailed test results were presented, including the failure mode, stress-strain curve, compressive strength, axial strain, and dilation property. The influences of the RA replacement ratio and the number of BFRP layers were analyzed. The test results indicated that BFRP tube-confined specimens exhibited strain hardening behavior in all of their stress-strain curves even if only a single layer of BFRP was used, and the failure was due to BFRP rupture along the hoop direction. The ultimate strength and deformability of RAC were significantly enhanced using BFRP confinement, with the confinement effect becoming more pronounced with increasing RA replacement ratios and BFRP layers. Compared to the unconfined specimens, the maximum enhancements in the ultimate strength and axial strain reached 2.8 times and 18.1 times, respectively, after BFRP confinement. Three typical theoretical models of FRP-confined concrete were employed to predict the ultimate conditions and axial stress-strain curves of the specimens. Finally, an improved model was formulated based on the test data to predict the ultimate conditions of BFRP tube-confined RAC cylinders. The proposed model was proven to predict the axial stress-strain curves, ultimate strength, ultimate axial strain with reasonable accuracy.

Enhanced rheological, crystallization, mechanical, and heat resistance performance of poly(L‐lactide)/basalt fibers composites via in situ formation of stereocomplex polylactide crystals

AbstractDue to its favorable mechanical strength, transparency, and biocompatibility, polylactic acid (PLA) has considerable potential as a biodegradable material. Nevertheless, developing high‐performance PLA composites through environmentally friendly and cost‐effective methods remains a significant challenge. In this study, the composites comprising poly(L‐lactide) (PLLA), basalt fibers (BFs), and poly(D‐lactide) (PDLA) are prepared through facile melt blending. The in situ formed stereocomplex polylactide (SC‐PLA) crystals improve the crystallization ability and rheological behavior of PLLA/BF/PDLA composites. Upon adding 5 wt% PDLA, BFs are nicely dispersed in PLLA matrix because of increased shear intensity. The synergistic effect of BFs and SC‐PLA crystals enhances the mechanical, thermomechanical, and heat resistance properties of PLLA. In particular, PLLA/BF/10%PDLA composites exhibit a Vicat Softening Temperature (VST) of 155.5°C, increasing by approximately 100°C over neat PLLA. Annealing treatment increases the Young's modulus, thermomechanical properties, and VST of samples while reducing their tensile strength. Interestingly, the tensile strength of the annealed PLLA/BF/10%PDLA composites is 50.2 MPa, twice that of the annealed neat PLLA due to the introduction of SC‐PLA crystals. Simultaneously improving the rheological, mechanical, and heat resistance performance of PLLA opens possibilities for expanding its potential applications in the industrial field.

Evaluation of basalt fibers and nanoclays to enhance extrudability and buildability of 3D-printing mortars

A study of the rheological and fresh mechanical properties of fly ash-cement 3D printing (3DP) mortars with six types of nanoclays (NC) as rheology modifiers, two sepiolites, three attapulgites and one bentonite, and reinforced with short basalt fibers (BF) was carried out. Fresh mortar properties were evaluated with a flow table test (FTT), cylindrical slump test (CST) and cone-penetration test (CPT) on samples left at rest and stirred before testing. Squeeze test (SQT) was carried out on samples cast-in-the-mold and 3D printed to compare the effects of 3DP on the fresh mechanical behavior. Extrudability was assessed with an electrical barrel extrusion device. NC and BF enhanced mortar cohesion by preventing water drainage and improving material extrudability. NC increased shear yield stress (τ0) over time on samples left at rest, enhancing reversible thixotropy. Besides, NC required larger amounts of superplasticizer, increasing open time windows. Among NC, Sepiolite in powder form showed the best fresh mechanical performance on 3DP samples. BF enhanced extrudability due to the bridging effect but also shows mechanical synergies with some NC. 3DP samples showed lower compressive yield stress and Young modulus evolution over time (σ˙ and Ė) than cast-in-the-mold samples, due to their layered structure.

Chemical resistance in acidic environments of alkali-activated lightweight composites based on secondary raw materials

The durability problems in Portland cement are related to decalcification of C–S–H; alkali-activated composites are proposed as alternative, focusing on acid exposure and resistance. They were prepared from recycled materials, basic oxygen furnace carbonated and desulfurization slags. The standard material is 100% metakaolin geopolymer compared to slag-based alkali-activated materials (AAMs) with and without reinforcement of fibers (basalt, and cellulose), added in 4 wt%. The acidic environments are H2SO4, HCl, and HNO3 N = 2.14 (10, 7.5, and 12.5 wt%, respectively). The chemical resistance is improved by the addition of basalt fibers. The decrease in weight loss is 48% in HNO3 and 47% in HCl for AAM-Bas sample, while for AAM-Cell it is 9% in HCl and 34% in HNO3. The compressive strength of the AAM and AAM-Bas samples remains constant after HCl attack, while this acid attacks cellulose samples, which are stable in HNO3 and have a compressive strength of 10 MPa.

Effect of Granite Fly Ash on Mechanical Properties of Basalt and Glass Fiber Reinforced Polymer Composite

The granite processing industry generates a substantial volume of residual granite waste daily. This residue is collected through a filtration process during the drying and heating stages of concrete mixture production. Utilizing this residue, known as granite fly ash (GD), offers a promising avenue for mitigating adverse effects due to this waste material. The present study undertakes an experimental investigation into the potential utilization of granite fly ash as a filler to enhance the mechanical properties of basalt/glass composites (BFRC/GFRC). The research focuses on assessing the density and tensile characteristics of the developed fibre-reinforced polymer (FRP) composites. Composite samples were fabricated by incorporating GD at varying loadings, i.e., 1 wt.%, 3 wt.%, and 5 wt.%. The FRP laminates were produced using hand lay-up and vacuum silicon mold curing techniques. The outcomes show a slight increase in density, in which a maximum of 7% increment at 5 wt% of GD in BFRC. Meanwhile, tensile properties displayedsignificant enhancements, especially FRP with 3 wt.% GD content, for both BFRC and GFRC. Notably, the addition of 1 wt.% GD resulted in a 9% increase in tensile strength and a substantial 27% increase in modulus for the BFRC composite. In summary, the study underscores the advantageous influence of GD incorporation, particularly within the 1 wt.%, 3 wt.%, and 5 wt.%, on the mechanical properties of both BFRC and GFRC composites.

Experimental study on the influence of fiber characteristics on the working property of underwater flowable solidified soil: Flowability, anti-dispersion, strength and anti-scour resistance

A series of laboratory tests were conducted to investigate the properties of fiber-reinforced underwater flowable solidified soil (UFSS) as a novel material for scour protection in marine structures. The tests included flowability, underwater anti-dispersion, unconfined compressive strength (UCS), and anti-scour resistance. Results showed that adding fibers reduced UFSS's flowability and significantly enhanced its underwater anti-dispersion, exhibiting a similar trend with increasing fiber content. Increasing fiber length initially decreased and then increased flowability, with the opposite trend for anti-dispersion. The least favorable fiber lengths for flowability were 6 mm for PVA fiber and 9 mm for both basalt and glass fibers, whereas these lengths were optimal for anti-dispersion. Fibers improved both UCS and anti-scour resistance of UFSS, with both properties first increasing and then decreasing as fiber content and length increased. Excessive fiber content or length reduced both properties. In this study, the optimal fiber content for improving UCS was 0.3% for PVA and 0.2% for basalt and glass fibers, with an optimal length of 6 mm for all three. An empirical exponential relationship between UCS, critical scour resistance velocity, and critical scour shear stress at typical times (t = 3 h, 5 h) was established for rapid prediction of UFSS's anti-scour resistance.

A combined multilevel computational and experimental approach for interfacial screening and mechanical reinforcement of basalt fiber/polyamide 66 composites

Silane coupling agents (SCAs) can improve fiber-resin interface issues, yet selecting an appropriate SCA experimentally is resource-intensive. Herein, a multi-level screening method combining simulation and experiments is proposed to identify SCA-enhancing bonding between SCAs and polyamide 66 (PA66) and the basalt fiber (BF) −PA66 interface. SCAs with organic groups composed of N and O exhibited superior interaction with PA66 due to the more pronounced negative and positive electrostatic potential (ESP) distributions. In SCAs-grafted BF-PA66 models, SCAs not only altered BF surface nanostructure but also changed the arrangement of PA66 main chains from parallel to interpenetrating BF surface atoms. Besides, (3-ureapropyl)trimethoxysilane (SCA6) significantly improved BF-PA66 bonding, which was experimentally validated by enhanced interlaminar shear and mechanical properties. O atoms on SCA6 and PA66 are more electronically bound and have the smallest ESP extremum, providing strong polar interaction sites. Additionally, both simulations and experiments demonstrated a transformation from adhesive to cohesive failure.

Cooperative effect of hybrid polyethylene-basalt fibers on crack width control and mechanical properties in ECC

Engineered cementitious composite (ECC) reinforced with polyethylene (PE) fiber has large crack width and high production cost, and these two shortcomings affect its application in practical projects. In this study, basalt fiber (BF) was hybrid with PE fiber to achieve cooperative effect, developing a PE/BF-hybrid fiber ECC (PE/BF-HyECC) with tighter crack width and more economic advantages. The impacts of different fiber content on the pore structure, mechanical, and cost performance of PE/BF-HyECC were investigated. The PE/BF-HyECC with positive cooperative effect of 1.5 vol.% PE and 1.0 vol.% BF had higher strength and tighter crack width compared to PE-ECC with 2.0 vol.% PE. Its cost performance ratio was 1.19 to 1.37 times that of PE-ECC with 2.0 vol.% PE. The better performance and higher cost performance of PE/BF-HyECC is expected to expand its practical application.

Investigating the influence of acid-base/KH550 composite surface modified BF on the properties of fiber-reinforced SBS-modified asphalt mastic

The surface properties of fibers significantly influence fiber-reinforced asphalt mastic (FRAM) performance. However, the impact of composite-modified basalt fiber (BF) on basalt fiber-reinforced asphalt mastic (BFRAM) remains unclear. This study examines the effects of acid-base/KH550 modified BFs on BFRAM performance, providing an experimental basis for further optimization. Tests included SEM and fiber leakage for BFs and separation, physical properties, DSR, and DMA for BFRAMs. The research indicates that (1) Composite modification enhances the fiber’s surface roughness, activity, oil-holding properties, and compatibility with SBS-modified asphalt. (2) Due to differences in acid-base etching, acid etching combined with KH550 promotes a more uniform and extensive coupling reaction with the BFs. In contrast, alkali etching with KH550 facilitates a deeper, localized reaction. (3) Composite modification of the BFs significantly improves the high-temperature rheological properties of the BFRAMs, with acid-base etching making the grafting reaction between the fiber and coupling agent more pronounced. At a test temperature of 82°C, the rutting factor of BFRAMs containing composite-modified (acid-etched + KH550) BFs is 2.7 times that of asphalt mastic without BFs. (4) The glass transition temperature of BFRAMs modified by acid etching and KH550 is 4.9°C lower than that of the original asphalt mastic, proving that composite-modified BFs enhance the low-temperature elastic deformation capacity of the BFRAMs.

Repair of ordinary concrete using basalt fiber reinforced geopolymer: High temperature resistance and micro structure evolution of adhesive interface

Good bonding properties in the interfacial transition zone (ITZ) between the substrate and the repair material are critical to the success of the repair, and a good repair material can act as a protective layer to reduce the impact of fire on the structure. In this paper, Ordinary concrete (OP), geopolymer mortar (GP), and basalt fiber reinforced geopolymer mortar (GPb) were poured as the three repair materials on the roughened surface of the old substrate. The bonded specimens were exposed to temperatures of 23 °C, 200 °C, 400 °C, 600 °C and 800 °C for 1 h. The interfacial bond strength of the bonded specimens was tested by slant shear test, and the physical phase change of the repair material and the microstructure of the ITZ were analyzed by microscopic test. The results showed that the mechanical properties and high temperature resistance of ITZ were best when the old substrate interfaces were grinded and grooved and GPb was used as the repair material. Compared with S-OP, the bond strength of S-GPb was 26.92 %, 27.43 %, 46.50 %, 44.26 %, and 97.02 % higher at different temperatures. The increase in interfacial bond strength can be attributed to three mechanisms: (1) Mechanical interlocking with the old substrate with a rough surface. (2) The increase in temperature accelerates the volcanic ash reaction, and the formation of hydration products further fills the voids at the ITZ, maintaining the strength and compactness of the ITZ. (3) The addition of basalt fibers can form an anchoring effect at the interface, reducing the risk of interfacial spalling and cracking caused by material shrinkage in the ITZ.

The Improving Role of Basalt Fiber on the Sulfate-Chloride Multiple Induced Degradation of Cast-In-Situ Concrete.

In salt lake areas, the cast-in-situ concrete structure has been corroded by the combination of sulfate and chloride for a long time. The incorporation of basalt fiber materials into concrete helps to improve the durability of concrete. In this paper, experiments were conducted to study the corrosion deterioration mechanisms of basalt fiber-reinforced cast-in-situ concrete under sulfate, chloride, and combined attack. The appearance, size, mass, flexural, and compressive strength of specimens were investigated during the immersion period to determine the changes in the physical and mechanical properties of specimens. Moreover, the microstructure and mineral changes of specimens during the immersion period were observed by Scanning Electron Microscope (SEM), Energy Dispersive Spectrometer (EDS), X-ray diffraction (XRD), and Thermogravimetric (TG)/ Derivative Thermogravimetric (DTG) analyses. Results show that premixed chloride has a significant detrimental influence on the strength development of cast-in-situ concrete, with concrete powder spalling occurring on the surface of the specimen. Severe corrosion degradation of specimens occurs under the external sulfate and internal chloride combined attack, resulting in lower flexural and compressive strength. The compressive strength and flexural strength of the corroded specimens decreased by 15.4% and 24.8%, respectively, compared with the control group at 28 days. Moreover, premixed basalt fiber has a beneficial influence on cast-in-situ concrete. When the basalt fiber content is 0.5%, the flexural strength of the specimen is increased by 16.2%. The filling and bridging effect of basalt fiber alleviates the negative effects caused by corrosion. In addition, increasing fiber content is beneficial for enhancing its effectiveness when the fiber content is less than 0.5%. This paper provides a valuable reference for the application of basalt fiber-reinforced cast-in-situ concrete under the condition of sulfate-chloride compound corrosion.

Improving the curing reactivity, interfacial strength, thermal and mechanical properties of phthalonitrile resin/basalt fiber composites by reactive organic coating

Phthalonitrile (PN) resin is a thermosetting resin with excellent properties, but its poor processability hinders its wide application. Meanwhile, as a high-performance green fiber, basalt fiber (BF) shows good overall properties, but the chemical inertness and smooth surface limits its application as well. In this work, a highly reactive organic coating polydopamine (PDA) was used to promote the curing of PN resin and enhance the interfacial interaction between the polymer matrix and the fiber cloth. The successful coating of PDA was verified by SEM observation, FTIR and XPS spectra. It was found that PDA could not only increase the polarity of BF, aid the infiltration of PN resin into the fiber cloth, enhance the interfacial strength, but also promote the consumption of cyano groups and increase the chemical crosslinking density. Consequently, the overall performance of the composites was enhanced. Specifically, the laminate 0.4DABF/BAPh showed flexural strength of 447 MPa and flexural modulus of 23.3 GPa, which was 131 MPa and 4.5 GPa higher than those of BF/BAPh. The glass transition temperature of 0.4DABF/BAPh was also 77 °C higher than that of BF/BAPh.

Size Effects in Climatic Aging of Epoxy Basalt Fiber Reinforcement Bar.

The purpose of this study was to obtain information on the influence of the size factor on the climatic aging of circular fiber plastics produced by pultrusion. The kinetics of moisture transfer was obtained in humidification and drying modes at 60 °C in samples of epoxy basalt fiber reinforcement bars: after 28 months of exposure in the extremely cold climate of Yakutsk and 30 months of exposure in the moderately warm climate of Gelendzhik. It was shown that the 2D Langmuir model adequately describes the kinetics. The diffusion coefficients in the reinforcement direction for bars with diameters of 6, 8, 10, 16 and 20 mm turned out to be significantly higher than in the radial direction. To clarify the aging mechanism of the bars and the tensile, compressive and bending strength, the coefficient of linear thermal expansion and the glass transition temperature of the epoxy matrix of the bars with a diameter of 6, 8 and 10 mm after 51 months of exposure in Yakutsk and 54 months of exposure in Gelendzhik were measured. It was shown that after climatic exposure, the deformability of the bars decreased with increasing diameter of the bar; the glass transition temperature increased more significantly in the bar with a smaller diameter. In 6 mm diameter bars, the compressive and bending strength limits decreased by 10-25 % due to the plasticizing effect of moisture. With the same depth of moisture penetration into the volume of the samples, its effect on the strength of thin bars was significant, and for thick bars, it was insignificant. An increase in the glass transition temperature by 6 °C, associated with the additional curing of the polymer matrix, occurred in the surface layer of the epoxy basalt fiber reinforcement bars and was revealed in bars with a smaller diameter.

Revamp of the eco-friendly grouting materials by mixing basalt fiber for earthen sites conservation: Compressive performance and constitutive models

Reinforcement techniques, including anchorage and sealing with grout, are frequently employed to protect earthen sites and minimize the impact of fissures, the effectiveness of these approaches relies heavily on the mechanical properties of grout. To enhance the strength and ductility of the conventional grout, an eco-friendly composite grouting material mixture basalt fibers of varying lengths and contents is prepared. The DIC-based UCS tests were conducted to evaluate its compressive performance. Constitutive models of the basalt fiber-reinforced grout, including elastic perfectly-plastic (EPP) and median nonlinear (MNL) constitutive models, were established respectively based on the equal energy rule and cross-sectional data analysis for simplification application and precision evaluation purposes. The results show that the mixture of basalt fibers resulted in a distinct semi-brittle failure mode for the grout, with a significant increase in its compressive strength, ductility, compressive fracture energy, and residual bearing capacity. However, the elastic modulus will be lower when the fibers are relatively longer. Considering the differences in the relations between performance parameters and fiber content, and length, the highest compressive strength was reached at the fiber length of 6 mm and the content of 0.2 wt%, while maximum ductility was achieved at 18 mm and 0.4 wt%. The fracture energy exhibits an approximate positive correlation with fiber content. In addition, the EPP and MNL constitutive models can effectively characterize the compressive mechanical behavior of semi-brittle materials to satisfy different requirements on the precision of engineering analysis. This study contributes valuable insights into the development of high-ductility grouting materials of earthen sites, and the establishment of constitutive models for semi-brittle materials.

Study on design optimization, road performance verification and preparation process selection of hybrid fiber reinforced asphalt mixture composite

To achieve long-lasting, high-strength, and sustainable asphalt pavement, this study prepared a hybrid fiber asphalt mixture using micron-scale calcium sulfate whiskers (CSW) and millimeter-scale basalt fibers (BF). The response surface method was employed to optimize the mix design, develop a prediction model, and verify road performance. The preparation process was refined based on the optimal mix design. The findings revealed that the best overall road performance was obtained with 5 % CSW content, 6 mm BF length, and 0.32 % BF content. The mixture demonstrated optimal performance with CSW wet mixing and BF dry mixing. Additionally, testing the fiber asphalt mixture at the mixture level was found to be crucial, as results can vary from those obtained at the mastic level. This study provides an in-depth analysis of the hybrid fiber asphalt mixture’s action mechanisms in material optimization, performance verification, and preparation processes, offering valuable insights for related research and engineering applications of hybrid fibers.

Study on the epoxy bonding properties of polyphenylene sulfide matrix composites reinforced by montmorillonite and basalt fiber

To improve the epoxy bonding properties of polyphenylene sulfide (PPS) matrix composites, CK-MMT and K-BF were prepared by modifying montmorillonite (MMT) and basalt fiber (BF) with cetyl trimethyl ammonium bromide (CTAB) and 3-Glycidyloxypropyltrimethoxysilane (KH-560) as the modifiers. CK-MMT/BF/TPU/PPS composites were prepared by injection moulding. The surface properties of the composites were tested and characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), etc. The epoxy bonding and mechanical properties were studied by combining the single-lap-joint tensile shear strength test and notched impact test. The results demonstrated the successful preparation of the modified MMT and BF. With the addition of CK-MMT and K-BF in different ratios, the surface roughness and the contents of polar groups of the composites increased, which could effectively improve the epoxy bonding properties of PPS matrix composites. When the additions of CK-MMT and K-BF were 10 and 25 wt%, respectively, the composites had the best overall properties. It demonstrated a single-lap-joint tensile shear strength was 7.56 MPa, representing a 220.34% increase over that of thermoplastic polyurethane/polyphenylene sulfide (TPU/PPS) and a 477.10% increase over that of pure PPS.

A finite element analysis method for random fiber-aggregate 3D mesoscale concrete based on the crack bridging law

Mesoscale modeling is an emerging analytical method that can be used to study fiber-reinforced concrete. However, fine fibers with micrometer diameters are distributed in millions in a standard specimen, so it is impossible to establish a mesoscale model and further analyze it, which severely limits the investigation of the reinforcement mechanism of fine fibers on concrete. This paper efficiently established a highly applicable mesoscale analytical model for random fiber-polyhedral aggregate concrete in Abaqus software based on a comprehensive examination of the crack bridging law and the supplementation of the fiber spacing theory, combined with the improvement of the algorithms of aggregate generation, fiber arrangement, and the judgment of the fiber-aggregate contact by the secondary development method of Python, as well as the matrix-dual arrangement method. Additionally, basalt fiber concrete and mortar specimens were prepared and tested, and the parameters of the model were calibrated to verify the model's authenticity. The result shows that the method proposed in this paper can accurately and efficiently perform mesoscale concrete analysis with fine fibers. In the peak load stage, the fiber has the strongest alleviation effect (Δ = 0.033) on the matrix damage, 10 times that of the crack initiation stage (Δ = 0.003). With the development of damage, fiber stress increases gradually from the crack initiation stage (0.68 σfu), and the growth rate (41.53 %) is the largest at the peak load stage (σfu), which reveals the complex dynamic bridging effect of fiber on the matrix. This investigation proposes a novel and broad applicability methodology for the finite element analysis of fiber-reinforced aggregate mesoscale concrete.