Use Of Fiber Reinforced Polymer Research Articles

Surface modification of fibres with silane for enhancing the durability of FRP composites as reinforcement for seawater sea sand concrete (SWSSC): A review

This review discusses the necessity of surface modification to effectively use fibre-reinforced polymers (FRPs) as reinforcements for seawater and sea sand concrete (SWSSC). FRPs can be a viable reinforcement material for SWSSC as an alternative to the traditional carbon steel reinforcement that will suffer unacceptably high rates of corrosion due to the very high chloride content of the SWSSC environment. FRPs exhibit mechanical properties similar to steels but suffer insignificant degradation/corrosion due to chloride. However, the fibres in certain FRPs (such as basalt FRPs and glass FRPs) suffer degradation due to attack by the alkaline environment of concrete, causing degradation in fibre-matrix interfacial strength and loss of FRPs’s overall mechanical strength and durability. Therefore, fibres used in such FRPs require suitable surface modification to ameliorate their degradation, enabling their practical use as reinforcements of SWSSC. While carbon fibre-reinforced polymers (CFRPs) demonstrate superior resistance to alkali-induced degradation, their widespread use in large-scale civil engineering is hindered by high costs. In this review, more economic alternatives, i.e., basalt fibre-reinforced polymers (BFRPs) and glass fibre-reinforced polymers (GFRPs) are critically reviewed. To enhance the durability of FRPs and mitigate alkali-induced degradation of the basalt/glass fibres, suitable surface modifications are necessary to safeguard the mechanical properties of FRPs. Underpinned by a comprehensive discussion on the necessity of surface modification of fibres for the use of FRPs in SWSSC environment, this review focuses on the potential of advanced approaches for surface modifications of the fibres, i.e., coatings of silanes, and silanes impregnated with graphene nanoplatelets (GNPs), graphene oxide (GO) and its functionalised derivatives or metal oxides (such as SiO2, ZrO2, Al2O3, TiO2 and CeO2). This review critically discusses the opportunities for suitable surface modification of basalt and glass fibres for enabling the durable use of FRPs as reinforcements for sweater sea sand concrete.

Utilizing Building Information Modelling Technology To Modelling Abutment: Revit

Building Information Modeling (BIM) has transformed the construction industry by offering a robust platform that integrates design, analysis, and construction processes within a single digital environment. This research explores the application of BIM technology, explicitly using Autodesk Revit, in modeling bridge abutments—an essential component in bridge construction that supports and distributes loads from the superstructure to the foundation. The study aims to demonstrate how BIM enhances the efficiency, accuracy, and sustainability of abutment design and construction. The methodology involves a comprehensive review of existing literature on BIM and bridge abutment design, focusing on technological advancements, case studies, and best practices. Additionally, practical implementation of BIM using Revit is conducted to develop detailed 3D models of abutments, incorporating architectural, structural, and geotechnical elements. The benefits of BIM in this context include improved collaboration among multidisciplinary teams, enhanced visualization capabilities for design optimization, and early detection of clashes and constructability issues. The research investigates the integration of Geographic Information Systems (GIS) with BIM to enhance site selection and environmental assessment phases, ensuring informed decision-making throughout the project lifecycle. Innovations in materials science, such as the use of fiber-reinforced polymers (FRP) and ultra-high-performance concrete (UHPC), are also considered for their potential to enhance the durability and longevity of bridge abutments. Ultimately, this study contributes to advancing the application of BIM in civil engineering, particularly in bridge construction, by showcasing Revit's capabilities in creating accurate, data-rich models that improve project outcomes.

A path-dependent stress-strain model of FRP-confined circular concrete columns derived from an energy balance approach

It is generally believed that the use of fibre-reinforced polymer (FRP) confinement can effectively improve the strength and ductility of concrete. Passive confinement is one of the key features of the behavior of FRP-confined concrete. Analysis-oriented models for passively confined concrete have been established on the base of the active confinement model by many researchers. Among them, a stress path-independent assumption was made for those passively confined concrete. However, in recent years, numerous researchers have found that the influence of stress path on the stress-strain relationship of confined concrete cannot be neglected. Therefore, in order to further understand and simulate the uniaxial behavior of FRP-confined concrete, this paper presents a stress path-dependent model of FRP-confined concrete based on an energy balance approach in which the extra work done by the active confining pressure in the stress path-independent model is considered. Firstly, experimental data comprising 341 sets of FRP jacket confined concrete tests and 28 sets of concrete-filled FRP tube (CFFT) tests were collected. Subsequently, the stress paths of the two types of specimens were identified based on the properties of FRP materials, and then the energy balance assumption was introduced, and finally a new stress path-dependent model was established using the energy balance approach. By comparing the predictions of the proposed model with collected experimental data and those of several existing models, it was observed that the proposed model can more accurately predict the ultimate stress of FRP-confined concrete and exhibit good agreement with the experimental stress-strain curves.

Analysis-oriented stress–strain models for ultra-high-performance concrete confined with fiber-reinforced polymer

The use of fiber-reinforced polymer (FRP) jackets or tubes as confining devices can significantly improve the compressive performance of ultra-high-performance concrete (UHPC). For FRP-confined UHPC, an analysis-oriented stress–strain model is essential for a comprehensive understanding of its compressive behavior and the development of design models. Although several analysis-oriented stress–strain models have been developed for FRP-confined normal-strength concrete (NSC), such models for FRP-confined UHPC are still lacking. In this study, an experiment is conducted to investigate the failure mechanism of UHPC confined with FRP under concentric compression, and the stress–strain behavior of the FRP-confined UHPC is analyzed using the stress–strain models of actively-confined UHPC. Results showed that the stress-path-independency assumption, which has been proven to apply to FRP-confined NSC, was inapplicable to FRP-confined UHPC. By modifying the confining pressure to consider the influence of stress-path dependency, an analysis-oriented model was proposed. The proposed model was verified using a collected test database. The results show that the proposed model accurately predicted the stress–strain behavior of FRP-confined UHPC.

Development of shear strength prediction model for RC beams strengthened with FRP strips based on a novel ensemble learning model

The use of fiber-reinforced polymer (FRP) strips as an external strengthening method has gained widespread acceptance for enhancing the capacity of aging reinforced concrete (RC) beams. Despite extensive research and practical applications, there exist unresolved issues necessitating further investigation, including interface bonding, failure mechanisms, and the development of accurate predictive models for shear strength, considering diverse parameters. This paper systematically reviews shear strength formulas applied in the strengthening of RC beams using FRP strips. An extensive experimental dataset is compiled from diverse sources to support the analysis. Utilizing this dataset, a novel ensemble learning model is developed for predicting the shear strength contributed by FRP strips. Following the training of this model, the important score of each input parameter is also assessed. The findings presented herein contribute to a deeper understanding of the strengthening effectiveness of FRP strips on RC beams.

Axial compression test on strengthening concrete cylinders by Fe-SMA/FRP-HDPE tube and rubber concrete cladding layer

This paper proposed a new method to strengthen and repair concrete columns, which combined active and passive confinement. The method involved the use of iron-based shape memory alloy (Fe-SMA) strips to quickly exert active confinement to these columns, followed by the use of fiber-reinforced polymer (FRP) and high-density polyethylene (HDPE) tubes as external passive confinement to improve the load-bearing capacity, durability, and ductility of concrete columns. Rubber concrete that performs high energy consumption and certain strength was used as the cladding layer to improve the impact resistance of the concrete column. This paper explored the effect of this method on the bearing capacity performance of concrete columns through axial compression tests and set three test variables, including different net-spacing of Fe-SMA, different FRP wrapping forms, and different FRP layers. The test outcomes showed that all three test variables obviously improved the load-bearing capacity and ductility of concrete columns, peculiarly when applying active confinement. Eventually, this paper proposed a theoretical model to predict the peak compressive strength of the specimen, which can provide a reference for designing this active-passive confinement strengthening method.

Investigation of the Effect of CFRP and GFRP Sheet Length on the Final Capacity of Reinforced Concrete Beams of Buildings in Coastal Areas

In the last two decades, the use of FRP (Fiber Reinforced Polymer) composites for flexural, shear, torsion, and enclosing reinforcement of various structural components has grown exponentially. In this paper, the effect of using FRP composite with carbon fibers and glass with different lengths on the behavior of reinforced concrete beams is investigated. Eight reinforced concrete beams with a length of 150 cm, a width of 15 cm, and a height of 20 centimeters were modeled by composite fibers with lengths of 80 cm, 100 cm, 120 cm and 140 centimeters. Then, the sample reinforced concrete beam was modeled in ABAQUS® , which the results were compared with the laboratory samples. It were observed that with increasing the length of FRP sheets, the strength of reinforced concrete beams compared to the sample concrete beam, increased by about 61%, 82%, 86%, and 87%, respectively. It was due to the high cost of FRP sheets and compressive strength required in these sheets that used optimally. Therefore, the length of FRP strengthening sheets can be optimized to reduce the cost of FRP sheets and use them efficiently.

Flexural Performance and Stress Calculation of External Prestressed Fiber-Reinforced Polymer-Bar-Strengthened One-Way Concrete Slabs.

External prestressing is widely employed in structural strengthening engineering due to its numerous advantages. However, external prestressed steel bars are prone to corrosion when exposed to the service environment. This paper is dedicated to examining the use of fiber-reinforced polymer (FRP) bars as external prestressing materials to strengthen one-way concrete slabs. Five one-way concrete slabs were strengthened with externally prestressed FRP bars with different prestress levels and different amounts of FRP bars, while one non-strengthened slab was used for comparison. The effects of strengthening on the flexural behavior, specifically the cracking load, ultimate load, stiffness and failure mode, were analyzed systematically. Moreover, the ductility and cost-benefit optimizing properties of the reinforcing design were discussed. The results show that external prestressed FRP bars significantly improve the cracking load, ultimate load and stiffness of one-way concrete slabs. The absence of a bond between the concrete and FRP bars overcomes the brittleness of the FRP bars, while the strengthened slabs exhibit satisfactory ductility and a higher post-yield stiffness and bearing capacity. Additionally, the cost/benefit ratio is optimized by increasing the prestress level, while a higher number of prestressed FRP bars is beneficial to ductility. Finally, a method for calculating the stress in prestressed FRP bars at ultimate loads was proposed. Irrespective of the prestressing material, this method is applicable to both strengthened beams and one-way slabs.

Evaluating the impact of different anchor configurations and patch arrangements on the performance of fiber-reinforced polymer (FRP) anchors

The use of fiber-reinforced polymer (FRP) anchors to enhance the efficiency of externally bonded (EB) FRP systems has received considerable attention in recent years. However, their widespread application has been constrained by the challenges associated with their installation due to complexity in anchor detailing. To date, there has been limited research aimed at simplifying anchor detailing while maintaining its efficiency. This paper presents an extensive experimental study involving 88 tests on concrete beams with anchored FRP material, with variations in the number of FRP strips, anchor material ratio (AMR), fan length, and rounding radius of the anchor hole. The study focuses primarily on different aspects of the anchor configuration. The first part of the study compares the performance of two anchor details, while the second part assesses the impact of different FRP patch arrangements on enhancing the performance of the anchors. The efficiency of the newly suggested end anchor detail was found to be equivalent to the previously used end anchor detail. The use of FRP patches over anchors proved very effective in certain cases but ineffective in others.

Offshore floating wind turbine foundation revolution enabled by fiber-reinforced polymer (FRP) reinforced cementitious materials

<p>Offshore floating wind turbines (OFWTs) are gaining popularity due to their superior wind energy capture and minimal visual impact. However, traditional steel support foundations for OFWTs are plagued by corrosion issues. This article proposes the use of Fiber-Reinforced Polymer (FRP) reinforced Ultra-High Performance Concrete (UHPC) composites, referred to as FRU composites, for OFWT foundations. Durability assessment of FRU plates under simulated marine environment is conducted based on accelerated aging tests on FRU plates. Scanning electron microscope (SEM) analyses are conducted to explore the fracture surface and interface between FRP and UHPC matrix. A series of tests are conducted and the test results of the FRU elements are summarized in this article. Strength design methodologies for FRU elements under various loadings are established based on summary of existing studies. Hydrodynamic analyses and comparative studies between FRU and steel OFWTs reveal that FRU OFWTs demonstrate improved stability and reduced motion responses under combined wind-wave-current loading conditions. The successful development of FRU composites is anticipated to revolutionize the OFWT industry by offering durable and cost-effective foundation options.</p>

Research on the application prospect of GFRP in reinforced concrete structure

The field of civil engineering needs to take advantage of new technologies to improve the quality of construction. The use of fiber-reinforced polymers (FRP) to improve the strength, durability, and sustainability of buildings is the main focus of this paper. Through the research and analysis of material properties, it was determined that the most suitable material in the field of civil engineering is glass fiber reinforced polymer (GFRP). Then find out the strengths of the method and existing problems, and analyze the future research direction. It is found that GFRP has made certain contributions to civil engineering, but there are still some shortcomings such as insufficient performance and not being familiar with by the society. In the future, it is necessary to study the design specifications and Aged Test methods of FRP, and find new materials possible to improve the performance of FRP at the same time.

Experimental Study of the Effect of Different Insulation Schemes on Fire Performance of FRP Strengthened Concrete: FIRECOAT and REALROCK

The past two decades have witnessed rapid advances in the use of fiber-reinforced polymer (FRP) composites in different engineering fields. Advantages such as high strength-to-weight ratio, corrosion resistance, and tailority have led to immense interest in the use of FRPs in wide spectrum repair and strengthening of structures. Despite their many advantages, FRPs are highly sensitive to high temperatures, which pose a major concern for fire potential structures such as buildings. Applying proper thermal insulation can enhance the fire performance of FRP and reduce the possible fire damage to the FRP strengthened element. This study set out to experimentally investigate the effectiveness of two insulation systems, “FIRECOAT” and “REALROCK” on fire performance of CFRP and GFRP strengthened concrete specimens. Various configurations and exposure durations were considered to evaluate the effectiveness of insulating materials. To perform the experiments, cylindrical concrete specimens were fabricated and strengthened using CFRP or GFRP. After insulating the specimens, they were exposed to a standard fire curve for two different durations of 30 and 60 min. The results indicate that less than 30 min of fire, both insulation systems can provide the required protection. During long exposure duration of 60 min, only REALROCK can provide the required thermal resistance for FRP-strengthened concrete. Within the tested materials, Fire Set 60 outperformed other insulating materials. It was observed that implementing Fire Set 60 in the innermost layer of thermal insulations has crucial importance in preventing the fire induced reductions in strength of FRP-strengthened concrete elements.

Influence of seawater and sea sand on early-age performance and cracking sensitivity of concrete

Due to resource constraints, there has been a growing demand for alternative sources of water and sand in construction engineering. Recent advancements in technology, such as the use of fiber-reinforced polymers (FRP) reinforcement or impressed current cathodic protection-structural strengthening (ICCP-SS), have enabled the utilization of seawater and sea sand, garnering significant research attention. The study investigated various aspects of four types of early-age concrete based on the temperature stress testing machine (TSTM) method, including fresh properties, basic mechanical properties, hydration temperature history, restraint stress, autogenous shrinkage, creep, and cracking sensitivity. The results showed that seawater significantly increased the early tensile strength of concrete, while sea sand had the opposite effect. Compared with ordinary concrete, seawater and sea sand increased the early autogenous shrinkage of concrete, and the impact of seawater was more significant. For the early creep of concrete, seawater and sea sand reduced the maximum compressive creep of concrete, and the effect of sea sand was more remarkable. Seawater increased the tensile creep of concrete, while sea sand decreased the tensile creep of concrete. The comprehensive evaluation index indicates that seawater and sea sand have no significant effect on concrete's cracking sensitivity. This research may serve as a valuable reference for the use of seawater and sea sand in concrete.

Professional Profile Map as a Powerful Educational Tool for Architects and Civil Engineers

Abstract The paper discusses the importance of the Professional Profile Map (PPM) in the context of architecture and civil engineering education. It acknowledges the dynamic nature of these fields due to technological advancements and evolving industry practices, emphasizing the need for professionals who possess practical skills in addition to academic knowledge. The PPM is introduced as a valuable tool that acts as a bridge between academia and industry by defining the essential knowledge, skills, and competencies (KSC) required for success in these professions. Furthermore, the paper discusses the role of the PPM in Erasmus+ projects, highlighting its ability to facilitate customization and adaptability in education. It encourages interdisciplinary collaboration, practical experience, and employability enhancement, aligning with the goals of Erasmus+ projects. A case study from the TAB4BUILDING project illustrates how the PPM was used to identify KSC related to the use of Fibre Reinforced Polymers (FRP) in construction. The PPM's role in harmonizing educational programs across different countries and promoting international collaboration is emphasized.

Decarbonization strategies of building materials used in the construction industry

Building materials like steel, cement, and concrete are mainly the most used man-made materials in the world and the core materials for the construction industry. The high demand for these materials is increasing rapidly, resulting in significant greenhouse gas emissions to the atmosphere and contributing to global warming; therefore, a crucial need exists to investigate their environmental impact and to find effective strategies to decarbonize the building material industry. This paper aims to review the available decarbonization strategies that can be implemented in the building materials industry, especially in the steel and cement industry, to decrease CO2 emissions associated with the production of building materials. It also proposes the use of alternative materials which have a reduced environmental impact compared to the traditional ones, like the use of fiber-reinforced polymer instead of steel for reinforcing structural elements or the use of alternative cement like geopolymer instead of ordinary Portland cement. The reported results of this study stated that the widespread production of concrete, cement, and steel leads to a negative impact on the environment. Additionally, the current standards for building materials are based on technical performance without considering their environmental impacts; therefore, using alternative materials helps to balance the technical and environmental performances. Utilizing geopolymer cement as a replacement for Portland cement reduced the CO2 emissions by 10 to 70%, while adopting Fiber-reinforced polymer instead of steel in structural members reduced the CO2 emissions by 4 to 75%, depending on the type of the FRP. Furthermore, reducing CO2 emissions either in steel or in the concrete industry requires developing new technologies, which will be a key factor in accomplishing developments in these sectors. A combination of decarbonization technologies should be implemented to achieve the desired reduction in CO2 emissions.[copyright information to be updated in production process]

Evaluating the behavior and bond properties of FRP spike anchors under confined conditions and elevated temperature

The use of fiber-reinforced polymer (FRP) anchors in combination with the conventional externally bonded reinforcement (EBR) installation technique is an effective method to prevent or postpone the debonding of FRP sheets. However, their behavior under confined conditions and elevated temperatures is still unknown. In such a framework, in the first phase, the current research aims to assess pullout test results for single FRP anchors with dowels ranging from 50 to 75 mm in confined and unconfined conditions. To achieve this goal, three concrete slabs with the dimension of 1550 × 1250 × 250 mm3 were cast. Experimental results showed that the bond strength of FRP anchors in confined conditions increased by about 50% compared to the unconfined conditions. Additionally, a comparison was made between the experimental results and the literature models. In the second phase, eleven pullout tests were conducted on the cylindrical specimens with the dimension of 150 × 200 mm2 (diameter × height) under confined conditions and elevated temperatures by considering different sustained load levels.The results showed as the temperature increases and FRP anchor is constantly loaded, it fails in a shorter time before the adhesive reaches its glass transition. Finally, a bond strength vs. temperature model was developed for FRP anchors in confined conditions and high temperatures.

Effect of internal defects on the thermal conductivity of fiber-reinforced polymer (FRP): A numerical study based on micro-CT based computational modeling

Use of fiber-reinforced polymer (FRP) composite in structural and aerospace fields is often restricted in a heated service condition. The thermal-induced degradation of FRP can be complicated by the internal defects with geometrical irregularities. This highlights the need for new characterization methods capable of revealing the thermal conduction process of FRP with different types of defects. To this end, the present study establishes a state-of-the-art methodology, namely micro computed tomography based finite element analysis (μCT-based FEA), for evaluating the influence of internal defects on the thermal conductivity of FRP. The modelling work through μCT gains an insight into the actual three-dimensional (3D) meso-scale structures for various species of defects (void, needle-like cavity, air pocket/unfilled bug hole, and delamination) in FRP. From the numerical ‘virtual’ experiments, the simulated through-thickness thermal conductivities range from 0.2196 to 0.2270 W/(m·K), which are comparable with the experimental data from literature. The investigation also discovers that the unfilled bug hole and delamination decrease the effective thermal conductivity of FRP, while these defects can cause sub-surface heat concentration. In contrast, the needle-like cavity has negligible effect on the through-thickness thermal conductivity. Increasing the water saturation degree of defects leads to an exponential increase in the thermal conductivity of FRP, especially when a large air cavity or delamination is incorporated into the composite. Based on transient analysis, the relationship among temperature, heat flux intensity and exposure time is numerically determined. The research findings can motivate the applications of μCT-based FEA in quality inspection/control of manufactured polymer composite products and even in improving the thermal non-destructive testing methods for defect detection of field composite structures.

Effect of Fire on Concrete Contribution to ShearResistance of GFRP RC Beams

The use of fiber-reinforced polymer (FRP) bars is becoming commonplace in various civil engineering applications due to the several advantages they offer over traditional materials. However, limited knowledge about some aspects of the behavior of FRP bars, particularly when subjected to severe fires, is hampering their widespread use. This paper presents the results of a research program to investigate the shear behavior of glass-FRP (GFRP)-reinforced beams exposed to severe fires. Three reinforced concrete (RC) beam specimens with a cross-sectional width and height of 150 mm and 300 mm, respectively, and with a total length of 1700 mm were constructed and tested under four-point bending load up to failure. The main test variables were the reinforcement ratio and the fire. The experimental results show that all beams failed as a result of diagonal tension cracking. The shear resistance and stiffness of the RC beams decreased when the beams are exposed to fire at the same reinforcement ratio. Keywords: GFRP bars, reinforced concrete beams, fire, shear capacity, crack patterns, modes of failure.

Strengthening of reinforced concrete beams by using FRPs-An overview

In recent years, the externally bonded reinforcing (EBR) method has been utilized to improve reinforced concrete (RC) constructions employing composites constructed of fiber reinforced polymers (FRP). Due to its strong nature, ideal reliability and suitability for use with concrete buildings when used, externally bonded Composites made of polymer with fibre reinforcement (FRP) are developing continually more popular in the construction sector for the treatment of degraded structures. This study's objective is to assess recent findings about the strengths, weaknesses, and potential of FRP enhanced constructions made of reinforced concrete (RC) under various situations for loading. In challenging environmental conditions that are static, dynamic, and environmental, FRP strengthening produces good results. Although it is yet unclear what causes debonding and FRP rupture when service loads and environmental exposures interact, these failure types are common. The acknowledgment of use of FRPs in enhancing RC constructions as techniques are developed for utilizing all of the material's strength, reducing brittleness and the danger of fires and unintentional damage decreasing usage of energy and carbon emissions the production process, and decreasing the material's significant upfront expense. The knowledge gaps according to the condition of the art are also identified in this report, along with possible FRP-enhanced structure research subjects that can advance knowledge and produce design standards.

Analytical model for near-crack debonding in fiber-reinforced polymer composite-overlaid metallic plates with a central crack

Extensive research has been undertaken on the use of fiber-reinforced polymer (FRP) in the strengthening of fatigue-damaged and fatigue-prone civil engineering metallic structures. Evaluation of the static load-bearing capacity and fatigue life of the so-strengthened structures necessitates the accurate prediction of the stress intensity factor (SIF) for an FRP-overlaid crack in a metallic structure. This paper first presents a new analytical model for predicting the near-crack interfacial debonding process and its effect on the SIF of a centrally cracked metallic plate that is bonded on both sides with an FRP overlay. The stress distributions in both the overlays and the metallic plate, the interfacial shear stress distribution, the crack opening displacement profile, and the SIF can all be found without the need for any a priori assumption of the near-crack interfacial debonding process/pattern. The accuracy of the analytical model is evaluated with both finite element predictions and experimental data. The analytical model is then used to advance our understanding of the mechanisms of near-crack interfacial debonding, including both the initiation and propagation of debonding, as well as the effect of near-crack debonding on the SIF. It should be noted that while the study was conducted with explicit reference to metallic plates bonded with FRP overlays, the analytical model is applicable to combinations of other materials as long as the substrate plate material is isotropic, and both components remain linear-elastic during the loading process.