Basalt Fiber Reinforced Polymer Research Articles

Multiscale Analysis of the Flexural Performance of FRP Reinforced Concrete Structures

Based on existing experimental data and analysis, seven different FRP bar models including Carbon Fiber Reinforced Polymer (CFRP), Basalt Fiber Reinforced Polymer (BFRP), Aramid Fiber Reinforced Polymer (AFRP), Glass Fiber Reinforced Polymer (GFRP), GFRP and CFRP combined (G-C), GFRP and AFRP combined (G-A), BFRP and CFRP combined (B-C), and BFRP and AFRP combined (B-A) were established. Finite element simulation analysis was conducted on seven different FRP bar combinations under static load bending tests. The flexural behavior of the specimens reinforced with different FRP bar combinations and their influencing factors were analyzed. The results showed that using AFRP as the reinforcement material for FRP composite bars in FRP reinforced concrete beams cannot effectively enhance the overall load-carrying capacity of the composite bars. The combination of CFRP with GFRP and BFRP bars significantly increases the stiffness of the FRP bar structure and improves the structural load-carrying capacity of the concrete beams.

Experimental Study on Flexural Behavior of RC Piles with Basalt Fiber-Reinforced Polymer Bars and Load Carrying Capacity Calculation

The practical application of BFRPB (Basalt Fiber-Reinforced Polymer Bars) as a support structure in foundation pit and slope engineering is relatively under-researched. The indoor tensile test presented in this paper is carried out on the bond between BFRPB and different labelled concrete. The mechanical characteristics of BFRPB, the failure characteristics, and the load-carrying capacity were analyzed. The results of this study demonstrate that the normal section stress of concrete cylindrical components with BFRP has a good linear relationship and supports the rationality of the flat section assumption. In circular reinforced concrete BFRP structures, the failure of the pile load occurs in four phases, and the cracking load is in the range of 51% to 67% of the normal yield load. The main bars increase in strain with load but become attenuated in the compression zone. The deformation of the main bars increases with the load but becomes muted in the compression zone. Based on the method of calculating the load-carrying capacity of GFRP-reinforced RC piles and the normal limit load-carrying moment obtained from in-door tests, the bending moment correction coefficient in the calculation formula for the load-carrying capacity of BFRP-reinforced RC piles was then obtained.

Comparative Performance Analysis of Small Concrete Beams Reinforced with Steel Bars and Non-Metallic Reinforcements

This research investigates the performance of small concrete beams that are reinforced with glass fiber-reinforced polymer (GFRP) bars, basalt fiber-reinforced polymer (BFRP) bars, and traditional steel bars. It addresses the limitations of traditional steel reinforcement, emphasizing the need for alternative strategies. Fiber-reinforced polymer (FRP) materials, including GFRP and BFRP, are examined for their mechanical characteristics compared to steel. The experimental program focuses on ultimate load-bearing capacity, deflection, deformation at different load levels, and failure modes. The concrete specimens, prepared according to Eurocode, consist of six small concrete beams measuring 80 × 120 × 1100 mm with varied reinforcements. The study reveals that GFRP-reinforced beams outperform BFRP and steel reinforcements in ultimate load-bearing capacity, showcasing enhanced structural performance. The GFRP-reinforced beams exhibit capacity and resilience characteristics surpassing those of both BFRP and steel, whereas the deflection observed was higher on both fiber-reinforced beams than on the steel-reinforced beams. The examination of failure modes reveals that the concrete beams that were reinforced with FRP bars showed a bending property before failure, while those reinforced with steel broke easily without bending much. This comprehensive research contributes to advancing our understanding of FRP materials’ application in concrete structures, paving the way for further optimization and overcoming limitations in reinforcement materials.

Structural design of self-centering socket precast post-tensioned segmental (SSPPS) bridge piers reinforced with BFRP tendons and stainless energy dissipation bars

In order to solve the construction and seismic problems of the existing precast pier connection methods, a self-centering socket precast post-tensioned segmental (SSPPS) bridge pier reinforced with basalt fiber reinforced polymer (BFRP) tendons and stainless energy dissipation (ED) bars is proposed. A detailed finite-element (FE) model is developed, validated with experimental results, and a parametric analysis of SSPPS is carried out. The bending performance, shear performance, anti-opening and closing and anti-overturning performance of the SSPPS pier are assessed through the simplified mechanical analysis. The findings demonstrate the SSPPS bridge pier is distinguished by its convenient construction and remarkable post-earthquake self-centering performance.

Behavior of geometrically-similar Basalt FRP bars-reinforced concrete beams under dynamic torsional loads

A numerical model utilizing 3D mesoscale simulation methods was developed to investigate the influence of strain rate on the torsional performance of geometrically similar Basalt Fiber Reinforced Polymer bars-reinforced concrete (BFRP-RC) beams, as well as the corresponding size effects. The model incorporates concrete heterogeneity, material strain rate effects, and the dynamic bond-slip relationship between BFRP bars and concrete. The torsional performance of BFRP-RC beams with different structural sizes and stirrup ratios was analyzed under different strain rates. The study yielded the following findings: (1) The damage degree of BFRP-RC beams increases with the rising strain rate. (2) Increasing strain rate and stirrup ratio enhances the beams’ torsional strength and ductility while attenuating the size effect, albeit not eliminating it. (3) The impact of increasing strain rate on beam strength, ductility, and size effect outweighs that of increasing stirrup ratio. Finally, based on the Bažant size effect law (SEL) combined with the simulation results, a new size effect law was proposed that can quantitatively consider the effect of strain rate and stirrup ratio on the torsional strength of BFRP-RC beams.

Bond performance of NSM FRP–concrete interfaces with epoxy under chloride‐salt conditioned environments

AbstractConcrete in coastal areas is susceptible to structural damage caused by corrosion and expansion of reinforcement. Near‐surface mounted (NSM) fiber‐reinforced polymer (FRP) bars have become effective for strengthening damaged reinforced concrete structures. The bonding performance of NSM FRP bars in concrete is a key factor limiting their application and promotion in civil engineering. In this study, the influences of the conditioned environment, such as the chloride salt concentration, immersion time, and bond length of the FRP bar, on the bonding performance were investigated experimentally. First, material properties in a conditioned environment were studied. Subsequently, the failure mode, bond stress–slip curve, and bond strength of the NSM FRP bar in concrete were investigated. Finally, the microstructure and chemical composition of the materials were revealed using scanning electron microscopy and energy‐dispersive spectroscopy (EDS) images of the materials under environmental conditions. The transfer mechanism of NSM FRP bars in concrete with epoxy was revealed. The results showed that the failure modes of the pullout specimens can be divided into epoxy splitting failure and basalt fiber‐reinforced polymer (BFRP) pulling failure. The chloride‐salt concentration was a critical factor affecting the bond properties, and the longer the bond length, the lower the bond strength. The microstructure clearly shows that the degradation of the bonding behavior at the interface of the NSM FRP bar in concrete in a conditioned environment is attributable primarily to the resin damage of the epoxy, resulting in pit corrosion. There was no significant damage to the fibers in the FRP bar, and the degradation was primarily due to resin matrix damage and interfacial debonding. The EDS results showed that the degradation of the epoxy resin and BFRP bars was caused by CO bond and SiO bond fractures, respectively.

Numerical analysis of shear critical BFRP-reinforced concrete beams containing basalt fibers

Simulation models were developed for concrete beams reinforced with basalt fibers (BF) and basalt fiber-reinforced polymer (BFRP) bars. Experiments were conducted on physical concrete beams to validate predictions of the numerical models. The effect of replacement of natural aggregates (NA) by recycled concrete aggregates (RCA) and the inclusion of BF on shear response of BFRP-reinforced concrete beams was then investigated numerically. The shear capacity of the beam models with 30–100% RCA decreased by 10–28 % relative to that of a control beam model with NA. The inclusion of BF at a volume fraction (vf) of 0.5 % to beam models with 30 % and 60 % RCA fully restored the shear capacity of the control model. At 100 % RCA, a maximum of 93 % of the shear capacity of the control model was restored at vf= 1.5 %. Research findings would assist practitioners in proper modeling of BFRP-reinforced concrete beams containing nonmetallic fibers.

Mechanical behaviour of TRM and FRP-reinforced concrete voussoir masonry specimens

This research investigates, both experimentally and analytically, the mechanical performance of masonry specimens made with special lightweight concrete voussoirs joined with cement mortar and reinforced with TRM (Textile Reinforced Mortar) made of either fibreglass mesh, TRM with basalt mesh or FRPs (Fiber Reinforced Polymers). The specimens represent a segment of an arch. A total of 18 specimens were tested, with one-third featuring each reinforcement solution. Another variable studied was the number of sides reinforced with TRM or FRP, either one or three. The specimens were tested under eccentric compression to analyze the effectiveness of the reinforcements. An analytical model was calibrated with the experimental results and used to extrapolate the experimental results in terms of strength capacity. The specimens that exhibited the best mechanical behaviours were those reinforced with TRM using basalt mesh. The FRP reinforcement experienced prematurely debonding with the voussoirs.

Mechanical performance and structural application of a novel basalt‐fiber‐reinforced ultra‐high‐performance seawater‐sea‐sand concrete (UHPSSC) with basalt coarse aggregate

AbstractAs unlimited resources, seawater and sea sand (SS) could be used as alternatives for fresh water and river sand in concrete constructions in areas with limited resources, such as mega‐cities and islands. To further improve the material efficiency, SS have been used to fabricate the ultra‐high‐performance seawater‐sea‐sand concrete (UHPSSC) in the literature. This work proposes a new type of UHPSSC, which incorporates basalt fibers to enhance the tensile property and coarse aggregate (CA) to improve the modulus. To investigate the contributing factors to the mechanical performance, 12 mixes of different fiber lengths, fiber volumes, and CA contents were designed and tested under compression and flexure. To verify the validity of the proposed UHPSSC in structural elements, six beam specimens reinforced with basalt‐fiber‐reinforced polymer (BFRP) bars were designed and tested. The influence of the tensile properties of the proposed UHPSSC and BFRP flexural reinforcement designs was analyzed. This research shows that with a proper mix design, the proposed UHPSSC has a maximum compressive strength of 140 MPa, exceeding the benchmark strength of 120 MPa for ultra‐high‐performance concrete. With different mix designs, the compressive strength of the proposed UHPSSC varies from 101.5 to 140.5 MPa and the flexural strength varies from 10.8 to 15.4 MPa at 28 days. At different curing ages, the basalt fiber length and volume have more significant impacts on the flexural strength but have limited impact on the compressive strength. Although an optimal CA content of 400 kg/m3 was found for the compressive strength and the CA content could amplify the influences of the fiber length and volume on the flexural strength. With the flexural reinforcement ratio varying from 0.58% to 1.29%, the UHPSSC beam specimens failed with expected flexural failure and the ultimate capacities varying from 118 to 183 kN, showing a predictable manner. Improving the tensile strength of the proposed UHPSSC could effectively enhance the cracking load and expand the stiffness degradation phase.

Effects of macro basalt fibers on the tensile behavior of ultra-high performance concrete

Macro basalt fibers (MBF), which is also named as basalt fiber reinforced polymer (BFRP) minibar, is a novel kind of fiber manufactured with BFRP. This work studied the effects of MBF on the tensile behavior of ultra-high performance concrete (UHPC) and proposed some MBF optimization recommendations based on the experimental results. Nine kinds of UHPC with MBFs and two kinds of UHPC with steel fibers or polypropylene (PP) fibers were designed for the tests of fiber distribution, density, compressive and tensile behavior. According to test results, UHPC with MBFs showed a more ideal fiber distribution compared to UHPC with steel fibers and PP fibers. For the samples with MBFs, UHPC with 3% twisted MBFs had the highest compressive strength, tensile strength and ultimate tensile strain, which were 138.9 MPa, 8.14 MPa and 1714 με, respectively. Compared to UHPC with steel fibers, UHPC with MBFs had slightly lower density and mechanical properties, but a similar stain-stress relationship. Thereby, the linear-exponential softening model was adopted to show the tensile stain-stress relationship of UHPC with MBFs. Based on the test results, three recommendations for optimizing MBF, which contained reducing fiber diameter for larger aspect ratio, optimizing fiber shape for higher fiber-UHPC bonding behavior and increasing the fiber modulus, were proposed to improve the mechanical properties of UHPC with MBFs.

A Comparative Study on Shear Size Effect of Steel-And BFRP-RC Shear Walls Under Cyclic Lateral Loads

ABSTRACT This paper presents a comparative study on the size effect behaviors of shear performances of concrete shear walls reinforced by steel bars and Basalt Fiber Reinforced Polymer (BFRP) bars. All the works are conducted through a two-dimensional meso-scale numerical simulation model representing the concrete shear wall. The horizontal reinforcement ratio and the sectional size are the main parameters concerned by the present study. Both the seismic behaviors under cyclic loading and the size effect behaviors of the shear performances were simulated and investigated. It can be concluded from the simulation results, (1) the use of steel bars or BFRP bars as horizontal reinforcement does not change the shear failure modes of concrete shear walls, (2) the size effect on the nominal shear strength of BFRP reinforced concrete (BFRP-RC) shear wall is more significant compared to that for steel-RC shear wall, (3) the increase of horizontal reinforcement ratio improves the shear capacity of the concrete shear wall, while weakens the size effect on the nominal shear strength, and (4) the size effect law for the nominal shear strength of steel-RC shear wall is applicable to BFRP-RC shear wall. Finally, the importance of considering size effect in the evaluation of shear performance of steel-/BFRP-RC shear wall is manifested by comparing the predictive results of several popular design codes with the simulation results.

Fatigue behavior of symmetric and asymmetric carbon and basalt fiber-reinforced polymer composites in transverse loading

Fatigue behavior of symmetric and asymmetric carbon and basalt fiber-reinforced polymer composites in transverse loading

Thermal evaluation of porcelain filler particles in basalt fibre-reinforced polymer composites for thermal applications

Thermal evaluation of porcelain filler particles in basalt fibre-reinforced polymer composites for thermal applications

Experimental and numerical study of the flexural behaviour of semi-precast slab reinforced with prestressed FRP bars

The performance of semi-precast slabs with prestressed basalt fibre-reinforced polymer (BFRP) bars under load is explored in this paper, using both experiments and computer simulations. The semi-precast slabs consist of precast concrete panels and cast-in-situ layers. The Precast panels are reinforced with BFRP bars prestressed at varying levels from 0% to 50% of their ultimate tensile strength. The experimental programme encompasses four-point bending tests conducted on five semi-precast slabs. For the numerical study, an ABAQUS model was used to perform finite element (FE) analysis, which aimed to simulate how the semi-precast slabs bent and to study how different factors affected their bending performance. The study parameters in this study were the grade of concrete and the reinforcement ratio. The results of this study show that prestressed BFRP bars significantly enhance load capacity and stiffness, while steel offers superior ductility. The computer models and the experiments matched well, as the average error between the two sets of data was less than 10%. Additionally, the parametric study reveals that enhancing the concrete grade or the reinforcement ratio can effectively enhance the flexural capacity and stiffness of the semi-precast slabs. In conclusion, this paper advocates for the utilisation of prestressed BFRP bars as an efficient and long-lasting reinforcement solution for semi-precast concrete slabs.

Efficient design of composite honeycomb sandwich panels under blast loading

Hybrid composite honeycomb sandwich structures (HCHSS) were employed due to high specific strength and stiffness and higher impact resistance property required for the aerospace and defence fields. The numerical modelling of the efficient HCHSS was developed for the core, front and back face plate using the C3D8R elements to determine the realistic failure behaviour for the honeycomb sandwich structure. The ConWep blast simulation loading was applied for the HCHSS. Advanced composite materials were used for the blast analysis of the HCHSS (carbon/epoxy, graphite/epoxy, woven basalt fibres/polypropylene and woven Kevlar fibres/polypropylene). The damage initiation and damage propagation based progressive damage modelling was developed and implemented in the VUMAT code for composite materials to determine the actual failure behaviour of the HCHSS. The face sheets used in this model were of a stainless-steel alloy AL-6XN. The sandwich structure was subjected to blast loads of 1, 2 and 3 kg of TNT and their performance was compared w.r.t both front and back-face deflection. The effectiveness of sandwich panels was further examined by altering the thickness of the core. Fibre-metal laminates (FML) were used in place of the steel face sheets in the panel in order to minimise its mass, and a thorough analysis of the panel’s mass in relation to its peak deflection was carried out. Upon analysing the results, it was noted that the panel with the basalt fibre reinforced polymer (BFRP) core gave the best results compared to other composite materials. For a blast load of 3 kg TNT, the peak back face deflection (PBFD) of HCHSS with a BFRP core decreased by 10.64%, 7.61% and 4.75%, respectively, compared to panels with CFRP, GFRP, and KFRP cores. The peak deflection of the panel decreased as the BFRP core thickness increased. The energy absorption capacity of the panel also increased with increasing thickness. Additionally, it was found that panels with BFRP cores and KFRP-steel laminate face sheets provided the optimum balance of strong blast resistant performance and light weight. Compared to the metallic (steel) sandwich panel, the mass of the sandwich panel with KFRP-steel laminate face sheets and BFRP core was reduced by 33%, but at the same time, its PBFD increased by almost 50%.

Damage assessment of concrete beams repaired with basalt fiber-reinforced polymer sheets through digital image correlation and acoustic emission

Basalt fiber-reinforced polymer (BFRP) has high mechanical strengths as a repairing material but exhibits low ductility. This paper investigates the damage process of reinforced concrete beams repaired using BFRP sheets, aimed at understanding the underlying mechanisms of achieving structural ductility when BFRP sheets are used. The damage process was assessed using digital image correlation (DIC) and acoustic emission (AE) techniques applied to monitor surface and internal damages of three full-scale concrete beams subjected to four-point bending. A beam was first loaded to crack, then repaired with BFRP sheets, and finally reloaded to failure. Surface strain fields and cracks were monitored using a DIC method, and cracking events were monitored using AE sensors deployed at different positions of the beams. The AE signals were analyzed to assess the damage process. The test results indicated that (1) tensile cracks predominated throughout the loading process; (2) the BFRP sheets hindered the widening of cracks and promoted the generation of fine cracks; and (3) the development of concrete cracks promoted interfacial debonding at steel-concrete and BFRP-concrete interfaces. A combination of different types of cracks and interfacial debonding helped the repaired beam achieve ductile flexural behaviors.

The splitting tensile strength and impact resistance of concrete reinforced with hybrid BFRP minibars and micro fibers

Basalt fiber reinforced polymer (BFRP) minibar is a novel kind of macro fiber, which is high-performed, green and durable. This study aimed to use hybrid BFRP minibars and micro fibers to control cracks of concrete from micro size to macro size, ultimately improving the mechanical properties of concrete. The compressive strength, splitting tensile strength and impact resistance of concrete reinforced with hybrid BFRP minibars and various micro fibers were tested and evaluated. The micro fibers contained micro basalt fibers, polyvinyl alcohol (PVA) fibers and steel fibers. Test results showed that the hybrid fibers provided significantly positive synergistic effects on the impact resistance, compressive and splitting tensile strength of concrete. Micro fibers improved the microcrack resistance capacity of concrete that increased with micro fiber content and modulus, but most of fractured during the development process of microcracks owing to their tiny size, showing little contribution to macrocrack resistance. BFRP minibar showed the pull-out failure, and the force preventing BFRP minibar from pullout bridged macrocracks, improving the macrocrack resistance capacity of concrete., but they seldom improved the microcrack resistance capacity of concrete because of its large size. Hybrid fibers improve the sustained resistance to crack during the whole crack development process owing to the synergistic contribution of hybrid fibers. Thereby, the concrete reinforced with hybrid 1.5% BFRP minibars and 0.75% micro steel fibers showed the highest compressive strength, splitting tensile strength and final-fracturing impact life under the failure probability of 30%, which were 22% 29% and 415% higher than those of concrete with mono 1.5% BFRP minibars. The method, which is that using hybrid macro fibers and micro fibers with high modulus and proper content to reinforce concrete, supports for further improving the mechanical properties of concrete in practice.

Experimental and numerical investigation of the flexural behavior of one–way RC slabs strengthened with near–surface mounted and externally bonded systems

This study investigated the flexural performance of one-way reinforced concrete (RC) slabs strengthened with two distinct strengthening systems: near–surface mounted (NSM) bars and externally bonded (EB) carbon fiber-reinforced polymer (FRP) strips. The NSM bars comprised four types: carbon FRP (CFRP), basalt FRP (BFRP), glass FRP (GFRP), and stainless–steel (SS) bars. The NSM–strengthened slabs showcased substantial enhancements in yield and ultimate load capacity, ranging from 20 % to 55 % and 59–123 %, respectively. In comparison, those strengthened with EB–CFRP strips displayed increases from 46 % to 107 % and 45–177 %, respectively, depending on the axial stiffness ratio of the strengthening system provided. Furthermore, the slabs reinforced with NSM–BFRP bars showed an 11–25 % improvement in their ductility indices. In contrast, the slabs reinforced with EB experienced a decrease in ductility ranging from 38 % to 50 %. This reduction was attributed to the differences in the modes of failure observed in both strengthening systems. The rupture of the NSM–FRP bars and the strain readings associated at the end of testing confirmed that the tensile strength of the NSM–FRP bars was fully exploited whereas the EB–CFRP strips utilized only 29–36 % of their ultimate tensile strain due to debonding. A finite element (FE) model was formulated to anticipate the behavior of the strengthened slabs. A strong correlation between the numerical predictions and the experimental outcomes was observed. The experimental–to–numerical ratios of the ultimate load ranged between 1.0 and 1.08 for the NSM–strengthened slabs and between 0.98 and 1.38 for the EB–strengthened slabs. This validated the FE models’ ability to capture the nonlinear performance of the strengthened slabs.

Some issues about the behaviour of external pre-stressed steel–concrete composite beams

A numerical experiment is performed to evaluate the behaviour of externally pre-stressed steel–concrete composite beams (EPSCCBs) up to their ultimate stages, considering second-order effects, tendon material and friction at tendon–deviator locations. The tendon force evolution with loading and slip at the steel–concrete interface is explored. A three-dimensional finite-element model is used to include all these aspects. The idea is to deconstruct the project of eight experimental EPSCCBs with different tendon profiles, considering the above-mentioned issues. The main findings indicate that the inclusion of second-order effects is essential for predicting the stress paths near the collapse loads and slip demands at the steel–concrete interface, while external tendons made of carbon fibre-reinforced polymer (CFRP) can be used as a substitute for classical steel ones, as they presented similar behaviours. The largest tendon force increments occurred for the CFRP tendons compared to other tendons made of glass, aramid and basalt fibre-reinforced polymers. Furthermore, it was found that a friction coefficient between 0.2 and 0.4 at the tendon–deviator interface better matches the available experimental tendon force evolution with loading. This finding seems to counteract the common assumption of using a null friction coefficient as suggested in other works.

Experimental investigation of RC beams strengthened with externally bonded BFRP composites

Abstract Objectives The goal of this article is to examine the behavior of reinforced concrete (RC) rays that strengthen superficially the basalt fiber-reinforced polymer (BFRP) fabrics. We found out that one ray without BFRP and seven rays enveloped within numerous lay-up arrangements. The importance of the study is to improve the flexural capacity of rays, using fiber-reinforced polymer procedure and examine the over-reinforcement technique. Methods Interestingly, we have examined under two-point loading, one BFRP fabric sheet flexure. Results Loads corresponding to the first crack/delamination and ultimate failure of the beams have been verified. Moreover, we have recognized the types of failure and load contrasted with deflection graphs that have been strategized at outstanding ray locations. Novelty Our investigation has unraveled the increased flexural strength of the strengthened RC rays after using coating. Additionally, we have applied pressure to the BFRP fabrics on both sides of the beams. Moreover, we have improved performance with flexural strength, ductility, and failure. Our results are novel and show that the flexural capacity of the wrapped RC rays increases by 46.6%. The ductility increased by 84%, and unfortunately, we had failed the FRB and the concrete had crushed.