Fiber Concrete Research Articles

Review of Fracture Properties and Research Methods of Fiber Recycled Concrete

Aiming at the background of the application of fracture mechanics in fiber recycled concrete as well as the shortcomings of the current research, the relevant results and progress are summarized from three aspects, namely, the basic theory of fracture mechanics of fiber recycled concrete and the research progress of the fracture properties of fiber recycled concrete as well as the testing methods of the fracture of fiber recycled concrete, respectively. The development history of the application of fracture mechanics in concrete is described, three fracture forms, fracture process zones and three softening curve models of concrete are introduced, and it is proposed to combine the bilinear softening curve and the virtual crack zone model to construct the ontological relationship of the whole process of concrete cracking. The current research status of recycled brick aggregate concrete and polypropylene coarse fiber concrete is introduced. The incorporation of recycled brick aggregate adversely affects the workability, basic mechanical properties and fracture properties of concrete. The reinforcing effect of polypropylene fibers on concrete can effectively improve the adverse effects of brick aggregate on concrete, which opens up the research prospect of green concrete and has high research value. The applications of three-point bending test, four-point bending test and DIC technique in the study of concrete fracture characteristics are introduced.

Experimental investigation and statistical evaluation of the effects of steel fiber aspect ratio and fiber rate on static and dynamic mechanical properties of concrete

Static and dynamic mechanical properties of steel fiber concretes were determined by experiments conducted on concretes produced using fibers of different volume ratios and aspect ratios, and variance analysis was applied to the experimental results and evaluated statistically. Flexural toughness, static and dynamic elasticity modules and Poisson ratios of steel fiber reinforced concrete (SFRC) were determined experimentally. Load-deflection curves under flexural loading and stress-strain curves under compressive loading were obtained and compared with each other. The most influential variable was aspect ratio of fibers affecting each feature. As the aspect ratio increased, the static elasticity modulus of concrete increased by 29.66 %, the dynamic elasticity modulus increased by 21.58 % and the Poisson ratio increased by 27.46 % compared to the control sample. The Poisson ratio of SFRC varies between 0.1825 and 0.246. A relation was obtained between static and dynamic modulus of elasticity. Mechanical properties were improved by using steel fibers with low amounts but high AR values. To achieve high flexural toughness, static and dynamic elasticity modules and Poisson ratio, aspect ratio of fiber should be increased.

STRENGTH ANALYSIS OF GGBS CEMENT WITH COCONUT FIBER

The infrastructure needs our country is increasing day by day & with Concrete is a main constituent of construction material in a significant portion of this infra-structural system, it is necessary to enhance its characteristics by means of strength & durability. When the cement is replaced with the GGBS, this GGBS provides the features like low heat of hydration, resistance to chemical attack, high compressive strength, better durability, and good workability and is also cost effective. This study shows the behaviour of GGBS based Concrete at the different molarity of NaOH like 4, 8, 10, 12, 14 etc and at different ratio of Na2SiO3/NaOH 0.5, 1, 1.5, and 2 respectively. This project work mainly focuses on advantages of GGBS as compared to the usage of cement and justification of certain properties like sustainability and durability. Study shows the hardened and gaining strength in Concrete in ambient temperature. To bring into focus the use of coconut fibers in Concrete and experimental program me was planned to study the material characteristics. The primary objective of this investigation is to study experimentally the properties of fibers. The properties of Concrete namely, compressive strength, were studied

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.

Mechanical properties of twisted galvanized iron fiber reinforced concrete with different contents and pitches

Utilizing galvanized iron (GI) instead of expensive steel fiber has become a new technique in concrete construction to improve the mechanical properties of concrete. Tensile strength tests confirm that twisted GI fibers could serve as a viable alternative to steel fibers. Using deformed fiber instead of straight fiber increases the strength parameters of concrete significantly. As such, twisted GI fibers were employed in this study to improve the quality of the concrete. The GI fibers were mechanically twisted with varying twisting pitches (4, 6, and 8 turns per inch) to create rope-like fibers. Thirteen different concrete mixtures were prepared using three different fiber contents (1.0%, 1.5%, and 2.0% by weight), maintaining a constant 25.4 mm fiber length. Compressive strength, split tensile strength, flexural strength, toughness indices, and residual strength of GI fiber reinforced concrete (GIFRC) were determined. Employing GI fibers increased the compressive strength to a range from 13.4% to 28.9%, the split tensile strength from 18.8% to 42.5%, and the flexural strength from 11.5% to 46.0% compared to the control specimen. Besides, twisted GI fiber increased compressive strength from 1% to 7%, split tensile strength from 2% to 11%, and flexural strength from 3% to 13% than those of plain GIFRC. Toughness indices and residual strengths were significantly higher for GIFRC beams compared to the control specimen, which indicated greater energy absorption capacity of GIFRC. Additionally, strength prediction models were established to estimate different strength parameters with varying twisting pitch of GIFRC. Experimental results resembled the proposed strength models. Therefore, using twisted GI fibers in concrete can be an excellent choice to improve the mechanical properties of concrete.

Effect of partial replacement of aggregate with oil palm shell on compressive and flexural strength of fiber concrete

Considerable innovation has been applied to concrete material to achieve specific properties such as density, strength, environmental sustainability, cost-effectiveness, among others. This study focused on the replacement of a portion of the aggregate with oil palm shell (OPS) to utilize previously underutilized waste. Concrete containing OPS typically exhibits reduced compressive strength compared to standard concrete. To enhance the compressive and flexural strength of OPS-infused concrete, the introduction of fibers was explored as an innovative measure. A particular focus was placed on using fibers from discarded masks due to the Covid-19 outbreak in Indonesia and globally. The non-biodegradable nature of polypropylene fibers in these masks necessitates further measures to minimize waste. Different proportions of OPS were incorporated into the concrete mix: 0%, 25%, 50%, 75%, and 100%, with each mix incorporating 0.20% mask fiber and 0.25% superplasticizer. Compressive strength testing employed cylindrical specimens with a diameter of 75 mm and a height of 150 mm, while flexural strength was assessed using beam specimens measuring 100 x 100 x 500 mm. The baseline compressive strength for concrete without OPS measured 17.76 MPa. The results of flexural strength testing revealed the highest value of 1.67 MPa for the 0% OPS mix and the lowest, 0.49 MPa, for the 100% OPS mix. Statistical analysis via analysis of variance (ANOVA) highlighted a notably significant correlation between the treatment combinations involving compressive strength and the replacement of OPS as coarse aggregate.

Comparative ultimate tensile strength of concrete and fibre concrete

The study is aimed at comparing the ultimate tensile stresses with respect to the crack resistance criteria of concrete and fibre concrete based on theoretical and experimental data. The resistance of concrete to cracking is determined by the ability to resist the formation and growth of cracks. According to the cracking resistance criterion, concrete deformations are limited by the ultimate tensile strength of the concrete matrix, insignificant for heavy concrete, and the introduction of dispersed reinforcement can significantly increase its tensile strength and crack resistance. Recommended methods for calculating the crack resistance of fibre concrete structures are based on the procedures, used to calculate the crack resistance of structures, reinforced with bars, and incompletely account the features of a fibre concrete as a structural material. In addition, although even a significant crack opening cause no effect on the bearing capacity of fibre concrete structures, generally accepted methods for calculating fibre concrete structures exclude cracking. The article discusses various options for calculating the ultimate tensile stresses of concrete and fibre concrete for ensuring crack resistance based on reference normative and experimental data. Dispersed reinforcement with metal fibres was established at least doubling the ultimate tensile strength according to the crack resistance criterion with even lowmodulus fibres effectively improving the crack resistance, which ensures a more reliable operation of structures, including during winter concreting.

Eco-Resilient (ECORE) Concrete Constructions: A New Challenge and A New Concept

This paper presents a new concept concerning the development of eco-resilient concrete constructions, that is to say constructions with a reduced carbon footprint and which can withstand mechanical stress and physico-chemical attacks worsened by climate change. After a critical analysis of current research and development policies in the field of concrete construction, a new global approach is proposed which should allow this concrete construction profession to better respond to the challenges caused by global warming. This approach is based on two strong ideas a) The use of fiber concretes in combination with passive or active reinforcements in all constructions susceptible to crack b) The use of numerical models based on non-linear finite element calculations in order to optimize the design of eco-resilient concrete constructions.

Post-Fire Behavior of Modified SIFCON One-Way Plates with Waste Tire Rubber under Flexural Load: Experimental and Numerical Study

In this research, an experimental and numerical investigation was conducted to study the flexural behavior of modified slurry-infiltrated fiber concrete slurry-infiltrated fibrous concrete (SIFCON) one-way plates after being subjected to a high temperature. The first part is an experimental work to ensure that the model developed is adequate, while the second part is a 3D finite element modeling of the SIFCON plates with the program ABAQUS using a sequentially coupled thermal displacement analysis. The experimental program included testing eight modified SIFCON plates containing waste powder rubber as a partial substitute for natural sand (0%, 5%, 10%, and 15%). All adopted specimens had identical dimensions (1,000 mm length, 300 mm width, and 50 mm thickness). Four specimens were exposed to fire for 2 hr at a constant temperature of 600°C, after which they were rapidly cooled by spraying them with water. Test results showed that increasing the powder rubber content of burned and unburned modified SIFCON specimens decreased the failure load and increased the specimens’ ductility factor, as well as the ultimate and service deflections. During the test, the failure of SIFCON was observed to be gradual, and the plates remained in contact even after the ultimate load was attained, whereas the failure of the reference mix (without wasted rubber) was observed to be more rapid than that of other SIFCON mixtures. For the flexural test, it gives desirable strength and good fire resistance. This study provides guidance for the study of SIFCON with waste rubber. Overall, the percentage of error between the experimental and numerical results for the load capacity and midspan displacement was about 5.05% and 8.65%, respectively.

Evaluation and optimization of volume fraction and aspect ratio of Polyethylene Terephthalate (PET) fibers in self-compacting lightweight concrete

ABSTRACT Use of Polyethylene Terephthalate (PET) fibers to reinforce the performance of self-compacting lightweight concrete (SCLC) is reported. Evaluation and optimization of the fiber addition is based on different properties. SCLC mixes were designed using three volume fractions Vf (0.5%, 0.75% and 1%) and three aspect ratios (l/d = 15, 30 and 45) of fibers. Slump flow, T500, L-box, segregation, density, absorption, porosity, compressive, splitting tensile and flexural strengths, modulus of elasticity, ultrasonic pulse velocity, thermal conductivity, flexural toughness, and impact resistance tests were performed and evaluated statistically. The results indicated that PET fibers in fresh SCLC negatively affected the flowability and passing ability, while they improved the segregation resistance. Compressive strength and modulus of elasticity slightly increased, whereas the tensile strength was significantly improved. Substantial improvements in flexural toughness, thermal and impact resistances were recorded, indicating beneficial enhancement in toughness and ductility. Less desirably, SCLC with PET showed slight increases in absorption and porosity. The statistical analysis showed that the fiber Vf controlled majority of the tested properties rather than the aspect ratio. Based on desirability function and multi-objective optimization, the optimum Vf and l/d were 0.65% and 35.6, respectively. Theoretical obtained values were verified experimentally for all properties with 0 to ±5% variance.

Preliminary results of three-point bending tests of concrete notched beams with different content of PVA fibers

During the last few decades, fiber-reinforced concrete (FRC) has been widely used in the construction industry to increase strength and toughness of concrete structural members. Different types of fiber have been used in FRC, with different dimensions, shapes, and mechanical properties. The addition of short, dispersed steel fibers in concrete gained large popularity in recent years and steel FRC (SFRC) is commonly used in specific structural applications (e.g., precast tunnel segments) and to partially substitute conventional internal transverse steel reinforcement. Nowadays, the addition of synthetic fibers in concrete is becoming increasingly popular, thanks to the ability of these fibers to delay the occurrence of microcrack and/or provide post-cracking tensile residual strength. Furthermore, synthetic fibers have better durability than steel fibers. Among different synthetic fibers, polyvinyl alcohol (PVA) fibers have shown promising results. In this paper, a preliminary experimental campaign is carried out to investigate the effect of micro and macro PVA fibers on concrete tensile strength and toughness. To this aim, three-point bending (TPB) tests are performed on concrete notched beams with different contents of PVA fibers. Results obtained with PVA-FRC are evaluated with respect to a corresponding plain concrete specimen, and the possible synergy between micro and macro PVA fibers embedded in concrete is assessed. Results show that PVA macrofibers increase the concrete post-cracking tensile residual strength.

The Effect of 0.8% Polyethylene Terephthalate Plastic Waste Substitution on the Flexural Strength on K-175 Concrete

The use of plastics in daily life continues to increase in a variety of uses. One of the most commonly used plastic that is difficult to decompose is Polyethylene Terephthalate (PET) plastic. In recent years, such as the construction industry, has been trying to reuse the waste as construction material. Therefore, this research aims to contribute by exploring the effect of PET plastic fiber substitution as fine aggregate on the flexural strength of concrete. PET plastic fibers were used at 0.8% as partial replacement of fine aggregates and then chopped to a size of 5 cm long, 1-3 mm wide. The test results indicate that concrete containing 0.8% PET plastic fiber as a substitution of fine aggregate has a higher flexural strength value of 4.32% which is better than normal concrete. Therefore, using recycled PET fiber in concrete is needed as an eco-friendly and sustainable construction material in the future in order to minimize PET plastic waste and replace it as a concrete constituent material.

Effects of rattan fiber length variation on mechanical properties, characterization, and microstructure of concrete

The study aimed to test how variations in fiber length affect the behavior of microstructures in concrete, as well as to characterize and analyze their mechanical properties. This research covers several specific objectives, including understanding the influence of different fiber lengths on micro and macrostructural aspects of concrete, assessing the mechanical properties of reinforced concrete with fibers of various lengths, and examining the relationship between fiber length and the mechanical performance of concrete. The results showed that the addition of rattan fibers in concrete can increase or even reduce tensile strength depending on the length of the fibers and their material characteristics. The addition of rattan fibers with a length of 30 mm results in a significant increase in tensile strength, while longer or shorter fiber lengths do not yield equally favorable results. Analysis of the chemical composition of concrete shows that the elements oxygen (O), calcium (Ca), and silicon (Si) predominate, with the addition of carbon (C), iron (Fe), aluminum (Al), magnesium (Mg), and Sulphur (S) elements in concrete with rattan fibers. Morphological observations using SEM on concrete, both with fibers and without fibers, provide an in-depth understanding of the structure of concrete surfaces microscopically

Investigation for optimal hybrid concrete blended with polypropylene and steel fiber to evaluate structural performance

In recent times, there has been a significant surge in interest regarding the usage of different materials to strengthen concrete. The capacity to enhance the tensile strength of concrete has made Hybrid Fiber Reinforced Concrete (HFRC) a subject of considerable interest. The purpose of this study is to investigate the effect of polypropylene and steel fibers on the strength of concrete. The variable parameters encompass varying proportions of steel and polypropylene fibers. A thorough experimental program, encompassing a total of 36 combinations, was executed with diverse HFRC mixtures. Based on past research, it is projected that fibers would perform better. One combination served as the control, while the other 35 combinations incorporated PPF in varying proportions (ranging from 0.2% to 1% of the cement’s mass) with an increment of 0.2%, along with steel fibers (ranging from 0.25% to 3% of the cement’s mass). Following this, split tensile strength tests (performed according to ASTM C 496) were carried out. Tensile testing was performed on specimens to observe the failure mode and tensile strength of the samples. The report ends by highlighting the research findings and outlining potential directions for additional study in this area. In conclusion, this study’s findings offer convincing evidence about the use of fibers in concrete.

Eco-friendly 3D printed concrete with fine aggregate replacements: Fabrication, characterization and machine learning prediction

During the last decade, 3D printing technology has experienced significant development, especially for concrete printing in construction. However, eco-friendly 3D printed concrete with fine aggregate replacements has not yet been sufficiently studied. Herein, twenty-five (25) mix categories are designed for use in 3D printed concrete. The mix materials include fine aggregates, silica fume (SF), ground waste rubber tire (Ru), and glass fiber (GF) composites. The mechanical characterization (i.e., stress-strain relations) are investigated, and the mechanical performance (i.e., compressive and flexural strengths) are reported. Numerical simulations are carried out to validate the experimental results, and satisfactory agreements are obtained. Machine learning prediction model is developed using the experimental and numerical results to predict the compressive and flexural strengths of the aggregate-mixed 3D printed concrete. An inverse relationship was observed between the rubber content and compressive strength of 3D printed concrete (RuC) printing imperfections is highly correlated with high rubber content. Similarly, increasing fiber volume in fiber concrete (FC) resulted in a decreased compressive strength due to reduced interlayer bond. Notably, hybridized concrete (HC) exhibited comparable strengths to fiber concretes at 1% fiber content, but a significant strength increase was observed at 5%, 10%, and 15% rubber contents with 2.5% fiber volume. Better stress-strain response (i.e., higher strength) is observed with larger SF content. It is evident that the addition of SF, GF, and Ru to concrete, improves cost efficiency and the stress-strain behavior of 3D printed concrete. The reported eco-friendly 3D printed concrete has a relatively low peak strength compared to normal concrete but shows traces of fatigue resistance. The eco-friendly 3D printed concrete provides the alternative for normal concrete for in-situ construction applications.

The strengthening theory of steel fiber reinforced concrete and its application in tunnel engineering: A review

Steel fiber reinforced concrete (SFRC) is one of the fastest growing and most widely used fiber concrete as engineering structural material. Considering the importance of steel fiber concrete in tunneling applications, this paper reviews and discusses the damage mechanism of concrete and the crack arresting effect of steel fiber, and further investigates the application of SFRC in tunneling based on the reinforcement theory of SFRC. It was obvious that (1) steel fiber can not only delay the cracking damage of concrete, but also improve the deformation capacity of concrete, SFRC has excellent impact resistance and high tensile strength; (2) all the reinforcement theories can be considered to be developed on the basis of composite mechanics theory and fiber spacing theory by comprehensive improvement, but still need to further explore the reinforcement theory reflecting; (3) the combination of steel reinforcement and steel fiber will reduce the use of tunnel reinforcement, which is proven to be a better choice, because the content of steel fibers in SFRC has a certain degree of unevenness, so steel fibers can not completely replace the application of steel; and (4) SFRC applied to the node part of the tunnel structure is more effective, but the relevant research is less, in addition, steel fiber concrete tunnel node seismic resistance will be an important direction for future research. The relevant research in this paper can provide reference for the practical application of SFRC in tunnel engineering and other research directions.

Effect of the Addition of Natural Fibers on the Mechanical Properties of Concrete

The use of rattan and bamboo fibers increases the compressive strength, tensile strength and improves the ductility of concrete. Shell ash also contains pozzolanic compounds that can improve the properties of concrete. In this study, rattan and bamboo were used as concrete fibers and seashell ash was used as filler. The purpose of this study is to measure the compressive and tensile strength of concrete. In this study, rattan and bamboo fibers were added to the concrete mix with a mix design 25MPa. The additive variation is 0%, 0.5%, 1%, 1.5%, 2%. The results showed that the average compressive strength at 28 days was 0.26.29 MPa, 0.5, 19.71 MPa, 1.21.69 MPa, 1.5, 24.72 MPa and 2.18 MPa. Accordingly, the average tensile strength after 28 days was 0.736 MPa, 2,359 MPa, 2,312 MPa, 2.453 MPa and 2,595 MPa. These results show that the addition of rattan and bamboo fibers to concrete can increase the crack resistance of concrete, while the optimal increase in compressive strength with the addition of rattan fiber is achieved only with the change of 1.5%. This indicates that the addition of 1.5% natural fibers improves the tensile strength of concrete.

Analysis on the Impact of Various Slope Ecological Restoration Techniques on Soil Fertility and Physicochemical Properties During the Summer Drought Period in Red Soil Area of Northeast Jiangxi Province

[Purpose] This study aims to investigate the impacts of three slope restoration techniques, namely, soil spray sowing, vegetation fiber, and vegetation concrete, on soil fertility, pH, and organic matter content during the summer drought period. The study also aims to explore the advantages of these three different restoration techniques, providing a basis for slope restoration in the Northeast Jiangxi region. [Methods] The study used experimental slopes established with three different restoration techniques: soil spray sowing, vegetation fiber, and vegetation concrete. Soil samples were collected during the rainy season in July 2022 and the drought season in September 2022. The changes in hydrolyzable nitrogen, available potassium, available phosphorus content, pH, and organic matter in the soil after restoration were comprehensively investigated. The study relies on the Qi-Wu expressway, and all the experiments are set on the slopes on both sides of the expressway. [Results]①For the soil restored using soil spray sowing during the drought season, the content of hydrolyzable nitrogen and available potassium was higher than that of the original soil, while the content of available phosphorus significantly decreased. The pH changed from acidic to weakly alkaline. ②For the soil restored using vegetation fiber during the drought season, although the content of available phosphorus increased, it was still relatively low. The content of available potassium decreased, but the total amount remained high. The content of hydrolyzable nitrogen was high and showed an increasing trend. The pH slightly decreased from weakly acidic to acidic. ③For the soil restored using vegetation concrete during the drought season, the content of hydrolyzable nitrogen, available potassium, and available phosphorus was high and showed an increasing trend. The pH slightly decreased, but it remained weakly alkaline before and after the drought. [Conclusion] Soil spray sowing, vegetation fiber, and vegetation concrete, all three restoration techniques, could demonstrate good performance during the drought period in the Northeastern Jiangxi region. In terms of their overall performance, the ranking from strong to weak is as follows: vegetation concrete > vegetation fiber > soil spray sowing. Soil spray sowing, as the most convenient and cost-effective slope restoration technique, could in the future incorporate additives that can improve local soil properties according to different regional characteristics. Vegetation fiber not only needs to improve soil acidity-alkalinity but should also appropriately incorporate phosphorus-containing additives. Vegetation concrete needs to address the issue of reducing soil acidity-alkalinity after restoration in the future.

Experimental study on flexural strength of slurry infiltrated fibrous concrete (SIFCON) produced with various percentages of waste steel fibers recovered from used tires

Slurry Infiltrated Fibrous Concrete (SIFCON), a modified version of Fiber Reinforced Concrete (FRC), addresses the challenge of increased fiber volume fractions. Commercially produced steel fibers are typically used in FRC and SIFCON. Efforts to reduce energy use in making commercial steel fibers have led to seeking alternative sources. Vehicular tires are typically recycled when no longer usable, yielding steel fibers among the products. Emphasis lies in recovering steel fibers from used tires as part of resource recovery from waste. Experimental work explored flexural strength in SIFCON with waste steel fibers at volumes from 4% to 7%. The study extended to assess SIFCON’s flexural strength with commercial steel fibers at similar volumes, aiming to correlate with those from waste steel fibers. M20 grade concrete and SIFCON slurry matrix specimens were cast as reference mixes for comparison. The flexural strength of SIFCON specimens with waste steel fibers recovered from used tires notably surpasses that of reference mixes and is comparable to SIFCON specimens with commercial steel fibers. Additionally, the two-layer technique proves effective in SIFCON using waste steel fibers from used tires, up to 6% volume. The test results show successful production of SIFCON from waste steel fibers recovered from used tires.

Behavior of Fire-damaged RC Beams After Strengthening with Various Techniques

High temperatures during a fire can significantly degrade the structural capacity of concrete. However, in many cases, it is possible to restore and strengthen fire-damaged concrete rather than completely rebuild damaged structures. The study considered two types of concrete (normal 25 MPa and high-strength 65 MPa) with two types of strengthening techniques: carbon-fiber-reinforced polymers (CFRP) sheets with different thicknesses of 1.5 and 2.5 mm and slurry-infiltrated fibrous concrete (SIFCON) jacketing with different fiber sizes of 20 and 30 mm. The numerical simulations and analyses were conducted to capture the complex behavior of fire-damaged concrete members (beams). A fire-damaged concrete beam subjected to an extreme or critical fire Exposure time (2 hours) was evaluated and modified using a finite element simulation approach. The simulation process included three stages: the first, subjecting the concrete beam to thermal loading; the second, reflecting the fire distribution map to another model of applying mechanical loading; and the third, involving the application of strengthening to the damaged model. The results showed that the strengthening using CFRP with a thickness of 2.5 improved the load-carrying capacity compared with SIFCON in both types of concrete. 200% improvement for the normal-strength concrete beam and a 136% improvement for the high-strength concrete beam, compared to the damaged beams. Doi: 10.28991/CEJ-2024-010-01-012 Full Text: PDF