Fiber-reinforced Concrete Specimens Research Articles

Mechanical Properties of Permeable Concrete Reinforced with Polypropylene Fibers for Different Water–Cement Ratios

Permeable concrete is a material that allows water filtration, reduces surface runoff, and maintains the natural water cycle. Previous studies have shown that its mechanical properties, particularly its compressive and flexural tensile strengths, are generally lower than those of conventional concrete, with significant variability observed among similar tests. This study investigates the compressive strength, flexural strength, and permeability of polypropylene fiber-reinforced permeable concrete specimens at two water–cement ratios (0.30 and 0.35). The mix design was conducted using the ACI 522R-10 method. Forty-eight cylinders measuring 200 mm × 100 mm were fabricated for permeability and compression tests. Additionally, 12 beams measuring 100 mm × 100 mm × 350 mm were produced and subjected to simple flexural testing in accordance with ASTM C78 guidelines. Compressive strength versus permeability and load versus deflection graphs were plotted, and the fracture energy was calculated for various deflections. The results indicate that the addition of fibers increased permeability and tensile strength but decreased compressive strength. Furthermore, an increase in the water–cement ratio led to higher compressive and flexural tensile strengths.

Experimental study on mechanical properties and breakage of high temperature carbon fiber-bar reinforced concrete under impact load

To investigate the effects of high temperature and carbon fiber-bar reinforcement on the dynamic mechanical properties of concrete materials, a muffle furnace was used to treat two kinds of specimens, plain and carbon fiber-bar reinforced concrete, at high temperatures of 25, 200, 400 and 600 °C. Impact compression tests were carried out on two specimens after high-temperature exposure using a Hopkinson pressure bar (SHPB) test setup combined with a high-speed camera device to observe the crack extension process of the specimens. The effects of high temperature and carbon fiber-bar reinforcement on the peak stress, energy dissipation density, crack propagation and fractal dimension of the concrete were analyzed. The results showed that the corresponding peak strengths of the plain concrete specimens at 25, 200, 400, and 600 °C were 88.37, 93.21, 68.85, and 54.90 MPa, respectively, and the peak strengths after the high-temperature exposure first increased slightly and then decreased rapidly. The mean peak strengths corresponding to the carbon fiber-bar reinforced concrete specimens after high-temperature action at 25, 200, 400, and 600 °C are 1.13, 1.13, 1.21, and 1.19 times that of plain concrete, respectively, and the mean crushing energy consumption densities are 1.27, 1.31, 1.73, and 1.59 times that of plain concrete, respectively. The addition of carbon fiber-bar reinforcement significantly enhanced the impact resistance and energy dissipation of the concrete structure, and the higher the temperature was, the more significant the increase. An increase in temperature increases the number of crack extensions and width, and the high tensile strength of the carbon fiber-bar reinforcement and the synergistic effect with the concrete material reduce the degree of crack extension in the specimen. The fractal dimension of the concrete ranged from 1.92 to 2.68, that of the carbon fiber-bar reinforced concrete specimens ranged from 1.61 to 2.42, and the mean values of the corresponding fractal dimensions of the plain concrete specimens after high-temperature effects at 25, 200, 400, and 600 °C were 1.19, 1.21, 1.10, and 1.11 times those of the fiber-reinforced concrete specimens, respectively. The incorporation of carbon fiber-bar reinforcement reduces the degree of rupture and fragmentation of concrete under impact loading and improves the safety and stability of concrete structures.

Bond performance between hybrid fiber-reinforced concrete and BFRP bars under freeze-thaw cycle.

This study applied the pull-out test to examine the influence of freeze-thaw cycles and hybrid fiber incorporation on the bond performance between BFRP bars and hybrid fiber-reinforced concrete. The bond-slip curves were fitted by the existing bond-slip constitutive model, and then the bond strength was predicted by a BP neural network. The results indicated that the failure mode changed from pull-out to splitting for the BFRP bar ordinary concrete specimens when the freeze-thaw cycles exceeded 50, while only pull-out failure occurred for all BFRP bar hybrid fiber-reinforced concrete specimens. An increasing trend was shown on the peak slip, but a decreasing trend was shown on the bond stiffness and bond strength when freeze-thaw cycles increased. The bond strength could be increased significantly by the incorporation of basalt fiber (BF) and cellulose fiber (CF) under the same freezing and thawing conditions as compared to concrete specimens without fibers. The Malvar model and the Continuous Curve model performed best in fitting the ascending and descending sections of the bond-slip curves, respectively. The BP neural network also accurately predicted the bond strength, with relative errors of predicted bond strengths ranging from 3.75% to 13.7%, and 86% of them being less than 10%.

Experimental Study on the Performance of Glass/Basalt Fiber Reinforced Concrete Unidirectional Plate under Impact Load

Fiber-reinforced composite materials have emerged as essential solutions for addressing the durability challenges of traditional reinforced concrete, owing to their lightweight nature, high strength, ease of construction, superior tensile capacity, robust corrosion resistance, and excellent electromagnetic insulation properties. This paper delves into the influence of loading rate and fiber bar type on the mechanical characteristics of concrete one-way plates through impact experiments on such plates fitted with glass/basalt fiber bars at varying drop weight heights. The test results reveal a direct correlation between increasing loading rates and escalating damage in fiber-reinforced concrete one-way plates, reflected in the progressive rise in peak deflection and residual displacement at the mid-span of the specimens. Notably, when subjected to higher impact loads, glass fiber-reinforced concrete specimens exhibit amplified deformation and intricate crack formations, consequently diminishing the overall deformation resistance of the plate. Furthermore, glass/basalt fiber-reinforced composites demonstrate notable vibration damping qualities, characterized by substantial residual displacement, minimal rebound, and rapid decay following vibration stimulation. Overall, glass fiber-reinforced one-way plates display marginally superior impact resistance compared to their basalt fiber-reinforced counterparts.

INVESTIGATING FIRE-INDUCED DAMAGE ON FIBER-REINFORCED CONCRETE SAMPLES USING NONDESTRUCTIVE EVALUATION METHODS

This research article investigates the effect of severe thermal exposure on the mechanical behavior of fiber-reinforced concrete specimens. Having been exposed to direct fire, the specimens undergo the fracture experiment to determine their mechanical properties. Fire-damage examination is performed with nondestructive techniques such as acoustic emissions (AE) and ultrasonic pulse velocity (UPV). The main purpose is to demonstrate that AE parameters, such as amplitude, cumulative hits, and energy, have a strong correlation with mechanical parameters and temperature. Besides that, acoustic emission monitoring is also an assessment tool of the structural integrity throughout the entire loading process. The distribution of AE events and the variation of key AE parameters across the load process give very useful hints to differentiate between intact and fired-damaged specimens. The fact that the AE can be used on-site to determine cracks means that it may be used as an alternative method to describe concrete's mechanical properties after fire exposures.

INVESTIGATING FIRE-INDUCED DAMAGE ON FIBER-REINFORCED CONCRETE SAMPLES USING NONDESTRUCTIVE EVALUATION METHODS

This research article investigates the effect of severe thermal exposure on the mechanical behavior of fiber-reinforced concrete specimens. Having been exposed to direct fire, the specimens undergo the fracture experiment to determine their mechanical properties. Fire-damage examination is performed with nondestructive techniques such as acoustic emissions (AE) and ultrasonic pulse velocity (UPV). The main purpose is to demonstrate that AE parameters, such as amplitude, cumulative hits, and energy, have a strong correlation with mechanical parameters and temperature. Besides that, acoustic emission monitoring is also an assessment tool of the structural integrity throughout the entire loading process. The distribution of AE events and the variation of key AE parameters across the load process give very useful hints to differentiate between intact and fired-damaged specimens. The fact that the AE can be used on-site to determine cracks means that it may be used as an alternative method to describe concrete's mechanical properties after fire exposures.

Study on the bond properties between BFRP bars and hybrid fibers reinforced recycled concrete under freeze-thaw cycles

To study the bond properties between basalt fiber reinforced polymer (BFRP) bars and hybrid fibers which were basalt fiber (BF) and polypropylene fiber (PF) reinforced recycled concrete under freeze-thaw cycles, conducting center pull-out tests to study the effects of three factors on the bond properties: the number of freeze-thaw cycles, the volume fractions of single fiber, and the volume fractions of hybrid fibers. Based on the data obtained from the test, establishing a four-stage bond-slip constitutive relationship model. The results showed that the failure modes were pull-out failure and splitting failure. The bond strength decreased when adding the single fiber, with a maximum reduction of 13.18%, but the peak slip increased, with a maximum increase of 69.92%. When the volume fraction of BF was 0.3%, it achieved the optimal effect. The bond strength and peak slip increased when adding hybrid fibers, with maximum increases of 13.47 and 130.08%, respectively. However, excessive fiber content will reduce the increase of bond strength. The bond strength between BFRP bars and hybrid fiber-reinforced recycled aggregate concrete (HFRAC) increased when the number of freeze-thaw cycles increased but decreased when the number of freeze-thaw cycles exceeded 50. The four-stage bond-slip constitutive relationship model fitted well with the bond-slip curves. Compared with other fiber-reinforced recycled concrete specimens, this model fitted better with the curves of HFRAC specimens after freeze-thaw cycles and had the best fitting effect for the internal crack slip stage of the curves.

Study on the influence mechanism of polypropylene fiber on crack propagation of concrete with existing cracks under uniaxial compression

In the process of long-term service of concrete, cracks are inevitable, especially in the state of tension and compression, the crack expansion speed is accelerating, which seriously affects the service performance of concrete, and even causes major disasters. While polypropylene fiber has remarkable cracking resistance, there is a lack of theoretical analysis on crack initiation and path expansion of concrete cracks with existing cracks during the compression process. In order to analyze the inhibitory effect of fiber on the propagation of pre-existing cracks, we performed uniaxial compression tests on concrete prisms containing pre-existing cracks. Acoustic emission technology was used to monitor each test group and obtain relevant data on the cracking process of the specimens. GDEM software was used to simulate typical test conditions, and the results were compared with the test results to further explain the mechanism of crack propagation and fiber suppression. The results show that: (1) fiber can inhibit the initiation and propagation of tension wing cracks at the existing crack tip. The higher the fiber content, the shorter the symmetrical wing cracks become. (2) With the increase of fiber content (0 ∼ 4 kg/m3), the failure mode of polypropylene fiber-reinforced concrete prismatic specimens changes from tensile failure to tensile-shear failure, and finally shear failure. (3) The crack initiation stress and peak strength of prismatic specimens first increase and then decrease with the increase of fiber content. (4) The increase of fiber content delays the crack initiation time, prolongs the time to the disappearance of the peak of the acoustic emission signal, and prolongs the total time of the failure process.

Effect of Macro Fibers on the Permeability and Crack Surface Topography of Layered Fiber Reinforced Concrete.

This paper describes the effects of macro fibers on permeability and crack surface topography of layered fiber-reinforced concrete (FRC) specimens with different layering ratios under uniaxial tensile load. The crack permeability of layered FRC specimens is investigated by a self-designed permeability setup. The topographical analysis of crack surfaces is investigated by a custom-designed laser scanning setup. The results show that when the fiber volume content and layering ratio of the FRC layer are constant, the tensile toughness of layered FRC specimens depends on the proportion of steel fiber in macro fibers, and with an increase in the proportion of steel fiber, the tensile toughness of layered FRC specimens increases. For the layered FRC specimens, the crack permeability is much lower than that of the normal concrete (NC) specimen. A significant positive synergistic effect on crack impermeability can be achieved by the combination of steel fiber and polypropylene fiber in the SF80PP2.3 specimen. The crack surface roughness parameter (Rn) values of the NC layer in layered FRC specimens are all higher than those of the NC specimen, and the crack surface Rn of the FRC layer in layered FRC specimens is higher than that of the unlayered FRC specimens. This can effectively increase the head loss of cracks and reduce the crack permeability of layered FRC specimens.

Effect of silica fume on fracture analysis, durability performance and embodied carbon of fiber-reinforced self-healed concrete

Nowadays concrete industry is trying to develop sustainable and energy efficient materials. One of the techniques is to develop crack free concrete. Therefore, this study focusses on the use of different supplementary materials like silica fume as substitute of cement to characterize the self-healing capacity of fiber-reinforced concrete in order to produce crack free concrete. The employed concrete consists of cement Type-I, synthetic fibers of polyvinyl alcohol (PVA) type with 0.5 % by the total volume of the mix, and two different types of self-healing materials. Cement was replaced by silica fume (SF) up to 15 % with an increment of 2.5 %, sand passing from sieve # 16 and CA of size 12 mm was used to produce high-strength concrete. Three-point bending test and microscopic examination were used to investigate the role of fibers on the self-healing efficiency of fiber-reinforced concrete specimens. Specimens were pre-cracked in the range of 50–100 μm at 14 days of curing and then, placed in water for 14, 56-days water condition to assess the effect of self-healing. Digital high-range microscope was used to measure crack width after pre-cracking and at the end of every exposure duration. After the specified exposure duration, specimens were microscopically observed again to check the crack healing and re-loaded up to final failure. Outcomes were taken in terms of peak load increase value after healing stage (FCPL), controlling crack propagation due to healing effect termed as (IFTR), effect of cracking on fracture energy in terms of (IFER) and Embodied Carbon and Embodied Energy. It was found from test results that the healing efficiency in terms of FCPL, IFTR, and IFER was improved, due to the use of silica fume as it has lower surface area then OPC, which triggers healing rate faster by accumulation of healed produces near crack surface in early age. Furthermore, durability performance in terms of embodied carbon and embodied energy is also reduced because of full-crack healing, which shows profound healing effect.

Effect of the Sizing Removal Methods of Fiber Surface on the Mechanical Performance of Basalt Fiber-Reinforced Concrete

In this study, comprehensive analyses were used to evaluate the physical and chemical properties of basalt fibers, employing a variety of instruments. Additionally, heat treatment and solvent treatment methods were used to eliminate the sizing present on fiber surfaces. The heat treatment process involved determining the optimal temperature and duration required to remove the sizing from the basalt fibers. The appearance, chemical composition, and crystal structure of the original fibers were examined, including those subjected to heat treatment and those treated with solvents. These treated fibers were then incorporated into concrete to create basalt fiber-reinforced concrete (BFRC) specimens for mechanical tests, which assessed their compressive, flexural, and splitting tensile strengths. The results revealed that heat treatment at 300 °C for 180 min effectively removed the sizing on the basalt fibers, and the heat-treated basalt fibers exhibited uniform dispersion inside the BFRC specimens. In addition, solvent treatment primarily removed the soluble components of the sizing. The mechanical properties of specimens with sizing-removed basalt fibers were better than the specimens with original basalt fibers and the benchmark specimens. Crucially, the mechanical test results demonstrated that BFRC incorporating heat-treated basalt fibers exhibited a superior mechanical performance compared to BFRC incorporating original fibers or fibers subjected to the solvent treatment.

Dynamic Splitting Performance and Energy Dissipation of Fiber-Reinforced Concrete under Impact Loading.

In this paper, the influence of different fiber materials on the dynamic splitting mechanical properties of concrete was investigated. Brazil disc dynamic splitting tests were conducted on plain concrete, palm fiber-reinforced concrete, and steel fiber-reinforced concrete specimens using a split Hopkinson pressure bar (SHPB) test device with a 100 mm diameter and a V2512 high-speed digital camera. The Digital Image Correlation (DIC) technique was used to analyze the fracture process and crack propagation behavior of different fiber-reinforced concrete specimens and obtain their dynamic tensile properties and energy dissipation. The experimental results indicate that the addition of fibers can enhance the impact toughness of concrete, reduce the occurrence of failure at the loading end of specimens due to stress concentration, delay the time to failure of specimens, and effectively suppress the expansion of cracks. Steel fibers exhibit a better crack-inhibiting effect on concrete compared to palm fibers. The incident energy for the three types of concrete specimens is roughly the same under the same impact pressure. Compared with plain concrete, the energy absorption rate of palm fiber concrete is decreased, while that of steel fiber concrete is increased. Palm fiber-reinforced concrete and steel fiber-reinforced concrete have lower peak strains than plain concrete under the same loading duration. The addition of steel fibers significantly impedes the internal cracking process of concrete specimens, resulting in a relatively slow growth of damage variables.

Effect of Fiber Orientation on the Fatigue Behavior of Steel Fiber-Reinforced Concrete Specimens by Performing Wedge Splitting Tests and Computed Tomography Scanning

This paper shows the relationship, in steel fiber-reinforced concrete, between fiber orientation and fatigue response through the combined use of computed tomography (CT), digital image processing (DIP) software and wedge splitting test (WST). The WST cubes were extracted from conventional 150 × 150× 600 concrete prisms and a groove and notch were carved on different faces in such a way that in half of the test specimens the fibers are oriented mostly perpendicular to the breaking surface and, in the other half, the fibers are mostly oriented parallel to the breaking surface. Fiber orientation was obtained using a CT device and DIP software from a miniprism extracted from the previously mentioned concrete prisms. The results show that there is a strong correlation between the crack-sewing fiber orientation on the one hand and fatigue life and crack opening rate per cycle on the other hand. Cubes with a higher percentage of fibers perpendicular to the crack surface (i.e., with a higher efficiency index) show a longer fatigue life and a lower crack opening rate per cycle, while cubes with a lower efficiency index show a shorter fatigue life and a higher crack opening rate per cycle.

A Deep Learning Approach for Autonomous Compression Damage Identification in Fiber-Reinforced Concrete Using Piezoelectric Lead Zirconate Titanate Transducers.

Effective damage identification is paramount to evaluating safety conditions and preventing catastrophic failures of concrete structures. Although various methods have been introduced in the literature, developing robust and reliable structural health monitoring (SHM) procedures remains an open research challenge. This study proposes a new approach utilizing a 1-D convolution neural network to identify the formation of cracks from the raw electromechanical impedance (EMI) signature of externally bonded piezoelectric lead zirconate titanate (PZT) transducers. Externally bonded PZT transducers were used to determine the EMI signature of fiber-reinforced concrete specimens subjected to monotonous and repeatable compression loading. A leave-one-specimen-out cross-validation scenario was adopted for the proposed SHM approach for a stricter and more realistic validation procedure. The experimental study and the obtained results clearly demonstrate the capacity of the introduced approach to provide autonomous and reliable damage identification in a PZT-enabled SHM system, with a mean accuracy of 95.24% and a standard deviation of 5.64%.

Modelling and Simulation of the Strength Properties of Ultra-High Performance Fiber Reinforced Concrete Specimens

The strength performance of UHPFRC with micro and hooked-ends steel fibers was studied in this paper using Finite Element (FE) modelling and simulation. The specimens were modelled in geometry, material, constraints, load and boundary conditions using ABAQUS package and dynamic explicit analysis was used to investigate the crack pattern, failure mode and stress-stain behaviour of the UHPFRC specimens when subjected to uniaxial compression and tension loading. Results from the FE simulation revealed that the surfaces of the UHPFRC specimens were still in good shape after attaining their ultimate resistance against compression and tension loading. The UHPFRC’s ultimate compressive strength of 260N/mm2 was just 7% higher than the experimental compressive strength. The UHPFRC exhibited both linear compressive stress-strain behaviour up to 89% of its peak strength and non-linear stress-strain behaviour with strain hardening and strain softening phases. Further findings also showed that the UHPFRC despite having ultra-high tensile strength did not undergo strain hardening phase as the vertical direction stresses were mainly distributed around the loaded section of the specimen. The FE UHPFRC models’ strength in compression and tension only has slight and negligible variations from the experimental strengths. The deformation and strength performance of the FE specimens are in perfect agreement with the experimental specimens. Therefore, FE modelling and simulation can be used as a reliable method of carrying out extensive studies on UHPFRC properties and performances.

A computationally efficient procedure for calibrating model parameters of multiple specimens

Model calibration can be a very intensive and time-consuming task, especially when dealing with non-linear and large finite element models. The computational effort further increases when multiple specimens have to be calibrated. This is typical of laboratory experiments where several specimens made with the same and/or different constituent materials are tested. This paper proposes a calibration procedure aimed at reducing the computational effort of multiple specimen model calibration. The calibration procedure combines the robustness of a surrogate-assisted evolutionary algorithm with the exploitation of a database collecting the results of the previously calibrated specimens. In this research, the proposed procedure is applied to the calibration of the parameters of a cohesive crack model for fiber-reinforced concrete specimens. The benefit of the proposed procedure is shown by comparing the results with those obtained from the same calibration method but without accounting for the previous results in the calibration of a new specimen.

A New Insight into the Design Compressive Strength of Ultra-High Performance Concrete

Compressive strength is one of the most critical mechanical properties of various types of concrete and is the main input variable for structural concrete design. Recently, with the advances in concrete technology, applications of fiber-reinforced concrete (FRC), including ultra-high performance concrete (UHPC), have grown rapidly. These new types of concrete are well known to exhibit superior mechanical characteristics such as compressive strength, fracture toughness, and durability compared to conventional concrete and thus are popularly used in urgent repair jobs where compressive strength is an important parameter to determine the required curing time until open to the public. Considering the importance of compressive strength in practice, this study aims to evaluate the effect of age and maturity on the compressive strength characteristics of three different types of concrete, namely UHPC with micro and macro steel fibers, FRC, and plain concrete, and to propose a new design strength criterion for UHPC. To this end, 180 concrete cube specimens were tested at 12 different ages between 3 and 126 days. The results indicated that irrespective of the type and presence of fibers, UHPC gained more than 90% of their ultimate compressive strength after only 21 days, while FRC and plain concrete specimens required a longer time (i.e., 28 days) to achieve 90% of their ultimate strength. Therefore, UHPC may adopt a 21-day compressive strength as a design input instead of a 28-day compressive strength commonly required for structural concrete specified by many codes of practice. Moreover, the obtained experimental results were compared with existing compressive strength predictive models in the codes of practice.

Adhesion and Sliding Constitutive Relationship between Basalt–Polypropylene Hybrid Fiber-Reinforced Concrete and Steel Bars

The extreme marine environment of the South China Sea Islands, which features high temperatures, high humidity levels and high salt levels, seriously affects the safety of building structures. The durability of concrete can be significantly improved by adding a basalt–polypropylene hybrid fiber, but its bonding mechanism with deformed bars is complicated. Therefore, the bonding performance of hybrid basalt–polypropylene fiber-reinforced concrete and deformed bars was studied by combining experiments and a theoretical analysis. We designed 38 groups of different concrete strengths, different thicknesses of concrete covers, different anchor lengths and different diameters of rebars. The bond strengths, bond–sliding curves and failure forms of each pull specimen were compared and analyzed. The results showed that the failure forms and bond–slip curves of the basalt–polypropylene hybrid fiber-reinforced concrete specimens and the ordinary concrete specimens were essentially the same. Based on the results of the axial tensile tests, an ultimate bond strength prediction model was developed, and a bond–sliding constitutive model for hybrid fiber-reinforced concrete and steel bars was also established.

Electro-Mechanical Impedance-Based Structural Health Monitoring of Fiber-Reinforced Concrete Specimens under Four-Point Repeated Loading

Fiber Reinforced Concrete (FRC) has shown significant promise in enhancing the safety and reliability of civil infrastructures. Structural Health Monitoring (SHM) has recently become essential due to the increasing demand for the safety and sustainability of civil infrastructures. Thus, SHM provides critical benefits for future research to develop more advanced monitoring systems that effectively detect and diagnose the damage in FRC structures. This study investigates the potential of an Electro-Mechanical Impedance (EMI) based SHM system for detecting cracks in FRC prisms subjected to four-point repeated loading. For the needs of this research, an experimental investigation of three FRC specimens with the dimensions 150 × 150 × 450 (mm) were subjected to three different loading levels where no visual cracks formed on their surface. Next, prisms were subjected to reloading until they depleted their load-carrying capacity, resulting in pure bending fracture at the mid-span. A network of nine cement paste coated Piezoelectric lead Zirconate Titanate (PZT) transducers have been epoxy bonded to the surface of the FRC prisms, and their frequency signal measurements were utilized for quantitative damage assessment. The observed changes in the frequency response of each PZT sensor are evaluated as solid indications of potential damage presence, and the increasing trend connotes the severity of the damage. The well-known conventional static metric of the Root Mean Square Deviation (RMSD) was successfully used to quantify and evaluate the cracking in FRC specimens while improving the efficiency and accuracy of damage detection. Similarly, the dynamic metric of a new statistical index called “moving Root Mean Square Deviation” (mRMSD) was satisfactorily used and compared to achieve and enhance accuracy in the damage evaluation process.

Bond durability performance of sand-coated BFRP bars in high-strength fiber reinforced concrete

The ever-increasing utilization of fiber-reinforced polymer (FRP) bars has led to a surge in research regarding their bonding properties with concrete. In this study, the bond durability behavior between high-strength fiber-reinforced concrete (FRC) and sand-coated basalt FRP (BFRP) bars was examined under three different environmental conditions including immersion in seawater solution at 50 °C for 3, 6, and 9 months, immersion in the sulfuric acid solution for 3, 6, and 9 months with an ambient temperature range of 20 to 30 °C, and exposure to 270 freeze–thaw cycles. A total of 60 pull-out samples were prepared using either basalt (B) fibers or polypropylene (PP) fibers. Plain concrete pull-out samples were served as controls. Test results revealed that all exposures have degraded the bond, leading to pull-out failure in all of the specimens. Exposure to 50 °C seawater was found to cause the most significant degradation. However, the use of basalt fibers helped to mitigate the loss of bond strength in the specimens when compared to plain concrete specimens. For example, after 3, 6, and 9 months of exposure to 50 °C seawater, bond strength retentions of 73.58%, 56.04%, and 34.47% were observed for basalt FRC (BFRC) specimens, compared to 39.64%, 49.37%, and 29.61% for plain concrete specimens. On the other hand, a lower retention in bond strength of 16.28% was recorded for polypropylene FRC (PPFRC) specimens at 9 months of exposure to 50 °C seawater. The bond stress-slip relationship of the tested bars was accurately predicted using two calibrated analytical models: the Eligehausen, Popov, and Bertero (BPE) model and the Cosenza, Manfredi, and Realfonzo (CMR) model. Notably, both models showed a strong correlation with the observed bond stress-slip relationships in the experiments.