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Manoj Kumar Rath. "Condition Assessment of a Reinforced Concrete Residential Building using Non-destructive Testing Methods - A Case Study." Electronic Journal of Structural Engineering 21 (November 30, 2021): 18–33. http://dx.doi.org/10.56748/ejse.21288.
Повний текст джерелаАнотація:
The present study deals with both experimental and numerical investigation on buckling effects of laminated composite plates subjected to varying temperature and moisture. A simple laminated plate model is developed for the buckling of composite plates subjected to adverse hygrothermal loading. A computer program based on FEM in MATLAB environment is developed to perform all necessary computations. The woven fiber Glass/Epoxy specimens were hygrothermally conditioned in a humidity cabinet where theconditions were maintained at temperatures of 300K-425K and relative humidity (RH) ranging from 0-1% for moisture concentrations. All the investigations are made with a symmetric cross-ply laminates. The present study deals with both experimental and numerical investigation on buckling behavior of laminated composite plates subjected to varying temperature and moisture concentration. Quantitative results are presented to show the effects of geometry, material and lamination parameters of woven fiber laminate onbuckling of composite plates for different temperature and moisture concentrations with simply supported boundary conditions with different aspect and side-to-thickness ratios. Experimental results show that there is reduction in buckling loads in KN with the increase in temperature and moisture concentration for laminates with clamped-free-clamped-free boundary conditions
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Protchenko, Kostiantyn. "Residual Fire Resistance Testing of Basalt- and Hybrid-FRP Reinforced Concrete Beams." Materials 15, no. 4 (February 17, 2022): 1509. http://dx.doi.org/10.3390/ma15041509.
Повний текст джерелаАнотація:
The fire resistance of fiber-reinforced polymer reinforced concrete (FRP-RC) elements depends on the temperature performance of the original concrete member, the fire scenario, and FRP reinforcement behavior. In this study, fire resistance tests are described, along with the characteristics obtained during and after applying elevated temperatures, simulating the effects of fire. The tested beams were reinforced with basalt (BFRP) bars and with a hybrid composite of carbon fibers and basalt fibers (HFRP) bars. Fire tests were performed on full-scale beams, in which the midsections of the beams were heated from below (tension zone) and from the sides for two hours, after which the beams were cooled and subjected to flexural testing. BFRP-RC beams failed before the heating time was completed; the best failure was associated with a BFRP reinforced beam that failed approximately 108 min after heating. Contrary to the BFRP-RC samples, HFRP-RC beams were capable of resisting exposure to elevated temperatures for two hours, but showed a 70% reduction in strength capacity when compared to non-heated reference beams. According to the author, the higher resistance of HFRP-RC beams was the result of the thermal expansion coefficient of carbon fibers employed in HFRP, which “prestresses” the beams and enables smaller deflections. The preliminary findings of this study can increase the feasibility of using FRP materials for engineering purposes.
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Mukhtar, Faisal M., and Olaniyi Arowojolu. "Recent developments in experimental and computational studies of hygrothermal effects on the bond between FRP and concrete." Journal of Reinforced Plastics and Composites 39, no. 11-12 (March 22, 2020): 422–42. http://dx.doi.org/10.1177/0731684420912332.
Повний текст джерелаАнотація:
The performance of fiber reinforced polymer externally bonded to concrete is greatly influenced by the environmental conditions to which it is exposed during service. Temperature and humidity are the two common environmental factors that alter the bond behavior of externally bonded fiber reinforced polymer. This paper reviews the experimental and computational approaches used to evaluate the hygrothermal effects—that is, the effect of temperature and humidity—on the durability of the fiber reinforced polymer–concrete bond, as well as on the bond’s performance under loading conditions. Some experimental testing conducted in the laboratory and in situ are critically reviewed and presented. Implemented approaches for improving bond performance under hygrothermal conditions and their modeling techniques are also presented. The paper concludes by discussing the review’s salient issues. The ongoing wide application of externally bonded fiber reinforced polymer creates opportunities for new research on improving and predicting the bond strength of fiber reinforced polymer concrete under hygrothermal conditions.
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Ogrodowska, Karolina, Karolina Łuszcz, and Andrzej Garbacz. "The effect of temperature on the mechanical properties of hybrid FRP bars applicable for the reinforcing of concrete structures." MATEC Web of Conferences 322 (2020): 01029. http://dx.doi.org/10.1051/matecconf/202032201029.
Повний текст джерелаАнотація:
One of the most common causes of the deterioration of concrete structures is the corrosion of steel reinforcement. Reinforcement made from fiber reinforced polymers (FRP) is considered to be an attractive substitution for traditional reinforcement. The most popular FRP reinforcing bars are made of glass fibers. Basalt fiber reinforced polymer (BFRP) is a relatively new material for reinforcing bars. The main drawback of BFRP bars is their low modulus of elasticity. A new type of bar made from hybrid fiber reinforced polymer (HFRP) in which a proportion of the basalt fibers are replaced with carbon fibers can be considered as a solution to this issue; such a bar is presented in this work. The HFRP bars might be treated as a relatively simple modification to previously produced BFRP bars. A different technical characteristic of the fibre reinforced polymer makes the designing of structures with FRP reinforcement differ from conventional reinforced concrete design. Therefore, it is necessary to identify the differences and limitations of their use in concrete structures, taking into account their material and geometric features. Despite the predominance of FRP composites in such aspects as corrosion resistance, high tensile strength, and significant weight reductions of structures – it is necessary to consider the behavior of FRP composites at elevated temperatures. In this paper, the effect of temperature on the mechanical properties of FRP bars was investigated. Three types of FRP bar were tested: BFRP, HFRP in which 25% of basalt fibers were replaced with carbon fibers and nHFRP in which epoxy resin was additionally modified with a nanosilica admixture. The mechanical properties were determined using ASTM standard testing for transverse shear strength. The tests were performed at -20°C, +20°C, +80°C for three diameters of each types of bar.
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Gailitis, Rihards, Andina Sprince, Tomass Kozlovksis, Leonids Pakrastins, and Viktorija Volkova. "Impact of Polypropylene, Steel, and PVA Fibre Reinforcement on Geopolymer Composite Creep and Shrinkage Deformations." Journal of Physics: Conference Series 2423, no. 1 (January 1, 2023): 012030. http://dx.doi.org/10.1088/1742-6596/2423/1/012030.
Повний текст джерелаАнотація:
Abstract For the last 40 years, there has been increased interest in geopolymer composite development and its mechanical properties. In the last decades, there have been cases when geopolymer composites have been used for civil engineering purposes, such as buildings and infrastructure projects. The main benefit of geopolymer binder usage is that it has a smaller impact on the environment than the Portland cement binder. Emissions caused by geopolymer manufacturing are at least two times less than emissions caused by Portland cement manufacturing. As geopolymer polymerization requires elevated temperature, it also has a significant moisture evaporation effect that further increases shrinkage. It can lead to increased cracking and reduced service life of the structures. Due to this concern, for long-term strain reduction, such as plastic and drying shrinkage and creep, fibre reinforcement is added to constrain the development of stresses in the material. This research aims to determine how different fibre reinforcements would impact geopolymer composites creep and shrinkage strains. Specimens for long-term property testing purposes were prepared with 1% of steel fibres, 1% polypropylene fibres (PP), 0.5% steel and 0.5% polyvinyl alcohol fibres, 5% PP fibres, and without fibres (plain geopolymer). The lowest creep strains are 5% PP fibre specimens, followed by 1% PP fibre, plain, 0.5% steel fibre and 0.5% PVA fibre, and 1% steel fibre specimens. The lowest specific creep is to 5% PP fibre reinforced specimens closely followed by 1% PP fibre followed by 0.5% steel and 0.5% PVA fibre, plain and 1% steel fibre reinforced composites. Specimens with 0.5% steel and 0.5 PVA fibre showed the highest compressive strength, followed by 1% PP fibre specimens, plain specimens, 1% steel fibre, and 5% PP fibre reinforced specimens. Only specimens with 1% PP fibre and 0.5% steel, and a 0.5% PVA fibre inclusion showed improved mechanical properties. Geopolymer concrete mix with 1% PP fibre inclusion and 0.5% steel and 0.5% PVA fibre inclusion have a 4.7% and 11.3% higher compressive strength. All the other fibre inclusion into mixes showed significant decreases in mechanical properties.
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Jain, Amit, and Bora Gencturk. "Multiphysics and Multiscale Modeling of Coupled Transport of Chloride Ions in Concrete." Materials 14, no. 4 (February 13, 2021): 885. http://dx.doi.org/10.3390/ma14040885.
Повний текст джерелаАнотація:
Chloride ions (Cl−)-induced corrosion is one of the main degradation mechanisms in reinforced concrete (RC) structures. In most situations, the degradation initiates with the transport of Cl− from the surface of the concrete towards the reinforcing steel. The accumulation of Cl− at the steel-concrete interface could initiate reinforcement corrosion once a threshold Cl− concentration is achieved. An accurate numerical model of the Cl− transport in concrete is required to predict the corrosion initiation in RC structures. However, existing numerical models lack a representation of the heterogenous concrete microstructure resulting from the varying environmental conditions and the indirect effect of time dependent temperature and relative humidity (RH) on the water adsorption and Cl− binding isotherms. In this study, a numerical model is developed to study the coupled transport of Cl− with heat, RH and oxygen (O2) into the concrete. The modeling of the concrete microstructure is performed using the Virtual Cement and Concrete Testing Laboratory (VCCTL) code developed by the U.S. National Institute of Standards and Technology (NIST). The concept of equivalent maturation time is utilized to eliminate the limitation of simulating concrete microstructure using VCCTL in specific environmental conditions such as adiabatic. Thus, a time-dependent concrete microstructure, which depends on the hydration reactions coupled with the temperature and RH of the environment, is achieved to study the Cl− transport. Additionally, Cl− binding isotherms, which are a function of the pH of the concrete pore solution, Cl− concentration, and weight fraction of mono-sulfate aluminate (AFm) and calcium-silicate-hydrate (C-S-H), obtained from an experimental study by the same authors are utilized to account for the Cl− binding of cement hydration products. The temperature dependent RH diffusion was considered to account for the transport of Cl− with moisture transport. The temperature and RH diffusion in the concrete domain, composite theory, and Cl− binding and water adsorption isotherms are used in combination, to estimate the ensuing Cl− diffusion field within the concrete. The coupled transport process of heat, RH, Cl−, and O2 is implemented in the Multiphysics Object-Oriented Simulation Environment (MOOSE) developed by the U.S. Idaho National Laboratory (INL). The model was verified and validated using data from multiple experimental studies with different concrete mixture proportions, curing durations, and environmental conditions. Additionally, a sensitivity analysis was performed to identify that the water-to-cement (w/c) ratio, the exposure duration, the boundary conditions: temperature, RH, surface Cl− concentration, Cl− diffusion coefficient in the capillary water, and the critical RH are the important parameters that govern the Cl− transport in RC structures. In a case study, the capabilities of the developed numerical model are demonstrated by studying the complex 2D diffusion of Cl− in a RC beam located in two different climatic regions: warm and humid weather in Galveston, Texas, and cold and dry weather in North Minnesota, Minnesota, subjected to time varying temperature, RH, and surface Cl− concentrations.
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Martynov, Gleb V., Daria E. Monastyreva, Elena A. Morina, and Aleksey I. Makarov. "Stress-strain state of fiberglass in conditions of climatic aging." Vestnik MGSU, no. 12 (December 2018): 1509–23. http://dx.doi.org/10.22227/1997-0935.2018.12.1509-1523.
Повний текст джерелаАнотація:
Introduction. Were investigated samples of fiberglass with the aim of its effective use in construction in the long term. Fiberglass is considered one of the most versatile and durable materials among polymer composite materials, however, and it is subject to destruction. It is known that one of the main reasons for reducing the specified characteristics and material properties is operational. At the design stage, it is necessary to determine the most reliable and economical materials used and, accordingly, be sufficiently aware of their strength and durability. Thus, in order to avoid the destruction of the material, as well as significantly enhance and prolong its service life, it is necessary to be aware of how exactly the properties of the material change over time. Regarding reinforced concrete, wood, brick and steel fiberglass is used in construction recently. This means that while the service life of the list of the most common materials in construction is known to a sufficient extent, manufacturers do not dare to use fiberglass as a material for critical structures. This occurs because changes in its characteristics, depending on operational factors, are not sufficiently studied for intervals exceeding 4-5 years of operation. Materials and methods. During the work, samples of fiberglass SPPS with a longitudinal and transverse arrangement of fiberglass were tested for climatic aging in a climatic chamber for 5 cycles simulating 5 years of material operation. All samples were subjected to tensile testing on a tensile testing machine R-5. Results. Destructive stresses were determined, calculations were carried out and elastic and strength characteristics of the samples were analyzed. On the basis of the obtained results, an analysis was carried out, conclusions were formulated about the use of fiberglass in the construction in the long term, as well as the influence of such operational factors as moisture, positive and negative temperatures, and ultraviolet radiation on the properties of fiberglass with a different arrangement of fiberglass. Conclusions. Found that the destructive stresses of fiberglass are significantly reduced during the first two years of operation, which must be considered when choosing fiberglass with the stated characteristics. Ultraviolet does not have a significant effect on the elastic-strength properties of the material, while during operat
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Hou, Hetao, Weiqi Fu, Canxing Qiu, Jirun Cheng, Zhe Qu, Wencan Zhu, and Tianxiang Ma. "Effect of axial compression ratio on concrete-filled steel tube composite shear wall." Advances in Structural Engineering 22, no. 3 (August 28, 2018): 656–69. http://dx.doi.org/10.1177/1369433218796407.
Повний текст джерелаАнотація:
This study proposes a new type of shear wall, namely, the concrete-filled steel tube composite shear wall, for high performance seismic force resisting structures. In order to study the seismic behavior of concrete-filled steel tube composite shear wall, cyclic loading tests were conducted on three full-scale specimens. One conventional reinforced concrete shear wall was included in the testing program for comparison purpose. Regarding the seismic performance of the shear walls, the failure mode, deformation capacity, bearing capacity, ductility, hysteretic characteristics, and energy dissipation are key parameters in the analysis procedure. The testing results indicated that the bearing capacity, the ductility, and the energy dissipation of the concrete-filled steel tube composite shear walls are greater than that of conventional reinforced concrete shear walls. In addition, the influence of axial compression ratio on the seismic behavior of concrete-filled steel tube composite shear wall is also investigated. It was found that higher axial compression ratio leads to an increase in the bearing capacity of concrete-filled steel tube composite shear walls while a reduction in the ductility capacity.
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Lumingkewas, Riana Herlina, Akhmad Herman Yuwono, Sigit Pranowo Hadiwardoyo, and Dani Saparudin. "The Compressive Strength of Coconut Fibers Reinforced Nano Concrete Composite." Materials Science Forum 943 (January 2019): 105–10. http://dx.doi.org/10.4028/www.scientific.net/msf.943.105.
Повний текст джерелаАнотація:
The compressive strength of the concrete reviewed in this study uses nanosilica and coconut fibers. The addition of coconut fibers to concrete contributes to the construction of sustainable and environmentally friendly building materials. The testing method carried out physically and mechanically. Testing the compressive strength of the nanoconcrete composite with variations in the amount of nanosilica which substituted with cement. Using variations of nanosilica composition, namely 0%, 0.5%, 1%, 1.5%, and 2% added with coconut fiber to determine the effect of compressive strength from nanoconcrete composite. The results obtained are the optimal value of concrete compressive strength with nanosilica is the addition of 2% nanosilica, which increases 43% of standard concrete. Moreover, on concrete with the addition of nanosilica and the addition of coconut fibers 1% test results in concrete compressive strength which is optimal in the addition of 0.5% nanosilica, which is 58% increase from normal concrete. The conclusion of this study that the addition of nanosilica and reinforced with coconut fiber will increase the compressive strength of concrete, this is an excellent composite material to get environmentally friendly building materials using.
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Harbi, Nibras Abbas, and Amer F. Izzet. "Performance of Post-Fire Composite Prestressed Concrete Beam Topped with Reinforced Concrete Flange." Civil Engineering Journal 4, no. 7 (July 30, 2018): 1595. http://dx.doi.org/10.28991/cej-0309198.
Повний текст джерелаАнотація:
The performance of composite prestressed concrete beam topped with reinforced concrete flange structures in fire depends upon several factors, including the change in properties of the two different materials due to fire exposure and temperature distribution within the composition of the composite members of the structure. The present experimental work included casting of 12 identical simply supported prestressed concrete beams grouped into 3 categories, depending on the strength of the top reinforced concrete deck slab (20, 30, and 40 MPa). They were connected together by using shear connector reinforcements. To simulate the real practical fire disasters, 3 composite prestressed concrete beams from each group were exposed to high temperature flame of 300, 500, and 700°C, and the remaining beams were left without burning as reference specimens. Then, the burned beams were cooled gradually by leaving them at an ambient lab condition, after which the specimens were loaded until failure to study the effect of temperature on the residual beams serviceability, to determine the ultimate load-carrying capacity of each specimen in comparison with unburned reference beam, and to find the limit of the temperature for a full composite section to remain composite. It was found that the exposure to fire temperature increased the camber of composite beam at all periods of the burning and cooling cycle as well as the residual camber, along with reduction in beam stiffness and the modulus of elasticity of concrete in addition to decrease in the load-carrying capacity.
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Koňáková, Dana, and Eva Vejmelková. "Reinforced Cement Composites – Effect of Hybrid Fibres on Selected Properties." Materials Science Forum 824 (July 2015): 179–83. http://dx.doi.org/10.4028/www.scientific.net/msf.824.179.
Повний текст джерелаАнотація:
In this article selected properties of a glass and polypropylene fibre reinforced cement composite materials are studied. They are determined either after preceding thermal treatment or during thermal loading. Basic physical properties (in concrete terms bulk density, matrix density and open porosity), mechanical properties (in concrete terms tensile strength and bending strength) are determined after subjecting the specimens to the pre-heating temperatures of 600°C, 800°C and 1000°C. The linear thermal expansion coefficient is measured directly as functions of temperature up to 1000°C. The critical temperature for the glass and polypropylene fibre reinforced cement composite when most properties are worsening in a significant way is found apparently 500°C.
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Xin, Jianda, Siqing Lin, Nannan Shi, Jianshu Ouyang, and Dahai Huang. "Effect of Reinforcement on Early-Age Concrete Temperature Stress: Preliminary Experimental Investigation and Analytical Simulation." Advances in Materials Science and Engineering 2015 (2015): 1–9. http://dx.doi.org/10.1155/2015/231973.
Повний текст джерелаАнотація:
For concrete under short-term loading, effect of reinforcement on concrete crack resistance capability is usually negligible; however, recent research results show that extension of this viewpoint to concrete under long-term loading (temperature variation) may be unsuitable. In order to investigate this phenomenon, this paper presents the experimental and analytical results of early-age reinforced concrete temperature stress development under uniaxial restraint. The experiments were carried out on a temperature stress testing machine (TSTM). Experimental results show that the coupling of reinforcement and concrete creep behavior influenced the concrete temperature stress development, and nearly 16% of concrete stress was reduced in the current research. Moreover, the cracking time of reinforced concrete was also delayed. Finally, based on the principle of superposition, analytical simulations of effect of reinforcement on concrete temperature stress have been performed.
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Lumingkewas, Riana Herlina, Sigit Pranowo Hadiwardoyo, Abrar Husen, and Saepudin. "The Effect of Nano Cement on the Compressive Strength of Coconut Fibers Reinforced Concrete Composite." Key Engineering Materials 831 (February 2020): 110–14. http://dx.doi.org/10.4028/www.scientific.net/kem.831.110.
Повний текст джерелаАнотація:
The development of nanotechnology continues to grow. The use of nanocement in concrete is expected to reduce the number of pores and improve hydration in concrete and provide more strength to the concrete. The use of natural fibers, in this case, coconut fiber can prevent cracks in concrete and make fiber concrete more ductile than ordinary concrete. The effect of using nanocement on coconut fiber concrete on the strength of the concrete to be studied. Methodology to complete the research objectives, use nanocement used in concrete, which has added coconut fiber. Tests reviewed the value of slump and specific gravity. Then, testing the compressive strength at 7, 24, 28 days. The results obtained were an increase of 48.19% in the strength of concrete. Further research needs to review on mixing nanocement with other natural fibers.
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Caldová, Eva, František Wald, and Anna Kuklíková. "Fire Test of Timber-fibre Concrete Composite Floor." Journal of Structural Fire Engineering 6, no. 2 (June 1, 2015): 147–54. http://dx.doi.org/10.1260/2040-2317.6.2.147.
Повний текст джерелаАнотація:
The subject of this paper is a description of experimental programme of timber-fibre concrete floor in fire. Furnace test was performed on one full-size floor specimen at the Fire testing laboratory PAVUS. Floor specimen was 4, 5 m long and 3 m wide, consisting of 60 mm fibre concrete topping on plywood formwork, connected to GL beams. It was subjected the standard fire for over 150 min. The membrane effect of the floor was progressively activated and the fire performance of timber-fibre concrete floor was better comparing to traditional design method. The project is a part of the experimental research that deals with the effect of membrane action of composite timber fibre reinforced floor slabs exposed to fire which is based on previous research on steel fibre reinforced concrete slabs. The main objective of the project is the preparation of the analytical model which can predict the fire resistance of such floors with dispersed reinforcement.
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Picazo, Álvaro, Marcos Alberti, Jaime Gálvez, Alejandro Enfedaque, and Abner Vega. "The Size Effect on Flexural Fracture of Polyolefin Fibre-Reinforced Concrete." Applied Sciences 9, no. 9 (April 28, 2019): 1762. http://dx.doi.org/10.3390/app9091762.
Повний текст джерелаАнотація:
The reinforcement of concrete by using polyolefin fibres may be considered in structural design to meet the requirements of the applicable code rules. To achieve a reliable use of such a composite material, use of full-scale real structures is needed. The conversion of lab testing data into real practice properties is challenging and significantly influenced by various aspects, among which the size effect is a key one. Given that the available literature does not report coinciding conclusions about such an effect on quasi-brittle materials reinforced with fibres, further research is justified. Therefore, this work studies the behaviour of notched beams with three proportional sizes by using self-compacting polyolefin reinforced concrete with a fibre volume fraction of 1.1%. Flexural testing was carried out according to the standard EN-14651, with the results revealing the existence of the size effect. In addition, a reduction of the residual strength identified in the larger specimens was observed in fracture surfaces with equal fibre content.
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Lehmann, Marek, and Wiesława Głodkowska. "Shear Capacity and Behaviour of Bending Reinforced Concrete Beams Made of Steel Fibre-Reinforced Waste Sand Concrete." Materials 14, no. 11 (June 1, 2021): 2996. http://dx.doi.org/10.3390/ma14112996.
Повний текст джерелаАнотація:
Inthis paper, we report the results of our research on reinforced concrete beams made of fine aggregate fibre composite, with the addition of steel fibres at 1.2% of the composite volume. The fine aggregate fibre composite is a novel construction material, in which the aggregate used is a post-production waste. Twenty reinforced concrete beams with varying degree of shear reinforcement, in the form of stirrups with and without the addition of steel fibres, tested under loading. The shear capacity results of reinforced concrete beams made of the fine aggregate fibre composite being bent by a transversal force, as well as the cracking forces causing the appearance of the first diagonal crack, are discussed. The stages of functioning of such elements are described. Furthermore, the effect of the steel fibres on the reduction of diagonal cracking is analysed. Computation of the shear capacity of the tested elements is performed, based on the Model Code 2010 and RILEM TC-162 TDF standards, for two variants of the compression strut inclination angle θ that measured during testing, and the minimum(in accordance with the Model Code 2010 standard). We found that the SMCFT method part of Model Code 2010 showed the best compatibility with the experimental results. The tests and analyses performed demonstrate that the developed novel fibrecomposite—the properties of which are close to, or better than, those of the ordinary concrete—can be used successfully for the manufacturing of construction elements in the shear capacity aspect. The developed fine aggregate fibrecomposite could serve, in some applications, as an alternative to ordinary concrete.
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Zhang, Li Na, Ci De Peng, and Ting Shu. "Study on Performance of Fiber Reinforced Concrete Composite Beam Structure." Key Engineering Materials 723 (December 2016): 720–24. http://dx.doi.org/10.4028/www.scientific.net/kem.723.720.
Повний текст джерелаАнотація:
FRP (fiber reinforced polymer material) having a high specific strength and specific modulus, good corrosion resistance and other advantages. FRP materials in civil engineering industry has been more and more popular, and gradually become a hot issue in the world. In order to take full advantage of a variety of materials and overcome the problems in the FRP structure, this paper mainly studies the composite structure of FRP and traditional materials, namely FRP-concrete composite beam structure. The mechanical parameters of FRP (mainly including CFRP and GFRP) were selected. And the stress -strain diagram of FRP materials are drawn. Through tensile tests on FRP (including CFRP and GFRP), FRP was found to belong to brittle materials. As well as the mechanical properties of FRP materials, the ultimate load analysis, the decision to use CFRP as a composite beam structural stiffness of the research materials. When considering concrete shrinkage, creep, temperature difference effect, the stiffness of composite beam meets the requirement. The deflection of FRP- concrete composite beam is verified by mechanical formula. The change of the concrete stiffness will affect the change of the structural stiffness of the FRP- concrete composite beam. As well as through an example, it is found that the concrete shrinkage and temperature can affect the change of the stiffness of the composite structure.
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Nugroho, Bintoro Siswo, Yoga Pebrianto, Irfana Diah Faryuni, and Asifa Asri. "Effects of Silica Nanoparticle Addition on Physical and Mechanical properties of Sugar Palm Fibers Reinforced Cement Composite Concrete." International Journal of Engineering and Applied Science Research 1, no. 1 (July 30, 2020): 24. http://dx.doi.org/10.26418/ijeasr.v1i1.42087.
Повний текст джерелаАнотація:
This study examines the effect of nanosilica addition to the physical and mechanical properties of sugar palm fibers (SPFs) reinforced cement composite concrete. The composite concrete ingredients are SPFs as the filler, cement and nano-silica as the matrix, CaCl2 as the catalyst, and water. Testing and fabrication of the composite concrete were performed according to the standard of ASTM C 1185 and ASTM C 1186. The results obtained show that, in general, the addition of nanosilica improves the quality of the composite concrete. A positive effect is attained by adding nanosilica to its optimum amount. The excessive addition of nanosilica reduces the quality of the composite. The composite's mechanical property that is negatively affected by the addition of the nanosilica is the elasticity, in which more nanosilica added stiffer the composite.
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Hosseini Mehrab, Alireza, Seyedmahdi Amirfakhrian, and M. Reza Esfahani. "Fracture characteristics of various concrete composites containing polypropylene fibers through five fracture mechanics methods." Materials Testing 65, no. 1 (January 1, 2023): 10–32. http://dx.doi.org/10.1515/mt-2022-0210.
Повний текст джерелаАнотація:
Abstract This paper investigates and compares the experimental results of fracture characteristics in various polypropylene fiber-reinforced concretes (high strength concrete, lightweight concrete, and engineered cementitious composite) on 90 three-point bend (notched and un-notched) beams. Five widely used fracture mechanics testing methods, such as work of fracture method, stress-displacement curve method, size effect method, J integral method, and ASTM E399, were used to investigate the fracture behavior. Results have demonstrated that fracture energy and fracture toughness improved as the dosage of polypropylene fibers increased in concretes. However, this improvement was different in concretes owing to various results of fracture mechanics testing methods and different properties of each concrete. Aggregates played significant role in the performance of polypropylene fibers on the fracture behavior of concretes. Among testing methods, the ASTM E399 showed the lowest values for the fracture toughness of concretes. Both work of fracture and stress-displacement curve methods exhibited appropriate results for the fracture energy of polypropylene fiber-reinforced concrete composites. The accuracy of size effect method was acceptable for determining size-independent fracture parameters of plain high strength and lightweight concretes. Furthermore, the J integral method showed more relevant results for the fracture toughness of polypropylene fiber-reinforced engineered cementitious composite.
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Nekora, Valeriia, Stanislav Sidnei, Taras Shnal, Olga Nekora, Iryna Dankevych, and Serhii Pozdieiev. "Determination of features of composite steel and concrete slab behavior under fire condition." Eastern-European Journal of Enterprise Technologies 6, no. 7 (114) (December 21, 2021): 59–67. http://dx.doi.org/10.15587/1729-4061.2021.246805.
Повний текст джерелаАнотація:
Methods for calculating the fire resistance of steel-reinforced concrete slabs made using profiled steel sheets under the influence of a standard temperature regime for more than 120 minutes are considered and analyzed. Research has been carried out to determine the heating parameters and the stress-strain state of steel-reinforced concrete slabs made using profiled steel sheets under fire conditions for more than 120 minutes. The results of this study allow to obtain indicators of temperature distribution for assessing the fire resistance of such structures for fire resistance classes above REI 120. Accordingly, the results obtained are a scientific basis for improving the existing method for calculating the fire resistance of steel-reinforced concrete slabs made using profiled steel sheets. The temperature distribution in the cross-section of structures was obtained using a general theoretical approach to solving the problem of heat conduction using the finite element method. Using the obtained temperature distributions, the parameters of the stress-strain state were determined based on the method of limiting states. To carry out the calculations, appropriate mathematical models were created that describe the effect of the standard temperature regime of a fire, to determine the temperature distribution at every minute in the sections of steel-reinforced concrete slabs with profiled steel sheets. A method is proposed for dividing the section into zones to take into account the decrease in the indicators of the mechanical properties of concrete and steel. A simplified method for the design assessment of steel-reinforced concrete slabs made using profiled steel sheets is proposed, which is consistent with the current EU standards and can be effectively used to analyze their fire resistance when establishing their compliance with the fire resistance class REI 120 and higher.
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Kang, Su Won, and Hyun Do Yun. "Effect of Cement Matrix’s Type on the Shear Performance of Lightly Reinforced Squat Shear Walls Subjected to Cyclic Loading." Advanced Materials Research 658 (January 2013): 42–45. http://dx.doi.org/10.4028/www.scientific.net/amr.658.42.
Повний текст джерелаАнотація:
This study was conducted to experimentally investigate the shear behavior of non-ductile squat shear walls with different cement matrixes such as normal concrete, fiber-reinforced concrete(FRC), and strain-hardening cement composite(SHCC). The cement matrix type’s effect in the lightly reinforced squat shear wall was evaluated through the testing of three one-third scale walls with a height-to-length ratio (hw/lw) of 0.55 under top displacement reversals. Experimental results show that the cement matrix type in the non-seismically detailed squat shear walls has a significant effect on the shear behavior and failure mode. Compared to reinforced FRC and SHCC shear walls, reinforced concrete wall exhibited brittle behavior. Reinforcing fibers in the FRC and SHCC mitigated the crack damage of wall and increase the shear strength.
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Jin, Sheng Ji, Zi Xin Liu, Zhong Liang Li, and Yan Ling Wang. "Research on Applied of CBF Composite Material in Engineering." Advanced Materials Research 838-841 (November 2013): 137–41. http://dx.doi.org/10.4028/www.scientific.net/amr.838-841.137.
Повний текст джерелаАнотація:
Based on the consequences of abundant relevant literatures, this essay expounded the latest mechanical properties research results of the concrete reinforced with CBF and its application on building structure reinforcement studied by the domestic and foreign scholars. Research suggests that the new composite material of concrete reinforced with CBF has many excellent engineering application characteristics such as good crack resistance, durability, permeability resistance, high temperature resistance and fire retardancy. CBF is a kind of good reinforcement materials with so many advantages including simple construction, favorable reinforcement effect and low cost. We can infer that CBF can be widely used in underground engineering port, deep-water wharf, cross-sea bridges and tunnels, cold region and other fields based on the good mechanical properties and durability of the concrete reinforced with CBF in the future.
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Rafiei, Pouya, Hoofar Shokravi, Seyed Esmaeil Mohammadyan-Yasouj, Seyed Saeid Rahimian Koloor, and Michal Petrů. "Temperature Impact on Engineered Cementitious Composite Containing Basalt Fibers." Applied Sciences 11, no. 15 (July 26, 2021): 6848. http://dx.doi.org/10.3390/app11156848.
Повний текст джерелаАнотація:
Engineered cementitious composite (ECC) is a new generation of fiber-reinforced concrete with high ductility and exceptional crack control capabilities. However, ECC can suffer a substantial reduction in ductility when exposed to elevated temperatures resulting in a loss of crack-bridging ability. In this study, the effect of adding basalt fiber (BF), which is an inorganic fiber with high-temperature resistance for the production of ECC, was studied. Moreover, the change in the mechanical properties of ECC, including compressive, tensile, and flexural strength, was experimentally investigated under elevated temperatures up to 400 °C. The results showed that the addition of BF to reinforced ECC improved the tensile and flexural strength of concrete effectively, but compressive strength marginally decreased. A significant decrease was observed in the range from 300 to 400 °C, while it increased smoothly when heated up to 300 °C. The compressive and flexural strength diminished after a slight strain gained when heated up to 100 °C. This work paves the way for future investigations focusing on the development of high-temperature resistance ECC.
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Al-Bazoon, Mustafa, Abdulkhaliq Jaafer, Haidar Haidar, and Abbas Dawood. "Shear Strengthening of Reinforced Concrete Beam Using Wire Mesh–Epoxy Composite." Civil Engineering Journal 8, no. 6 (June 1, 2022): 1205–26. http://dx.doi.org/10.28991/cej-2022-08-06-09.
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This experimental research aims to study the use of wire mesh–epoxy composite (WMEC) as a shear-strengthening technique for reinforced concrete (RC) beams by focusing on the following parameters: (1) presence of shear reinforcement in the shear span; (2) type of strengthening technique (U-jacketing, vertical U strip, or inclined strip); and (3) number of wire mesh layers (three or six layers). Nine simply supported rectangular RC beams were tested under two monotonic point loads. The testing specimens were divided into two groups: (1) five beams without shear reinforcement and (2) four beams with shear reinforcement. Load–deflection relationship, shear ductility index, beams’ stiffness, energy absorption, crack propagation, mode of failure, and strain were studied for all testing specimens and compared with those of the control beams to measure the improvement from WMEC addition. Results showed that all WMEC types enhanced the shear capacity. Among the three shear-strengthening types, the continuous U-jacket scheme had a higher effect, increasing the shear capacity between 33.4 and 95.9% and the shear ductility index by 23% relative to those of the reference specimens. The shear capacity improvement by WMEC for the beams without shear steel reinforcement was greater than that for the beams with shear reinforcement under the same shear-strengthening configuration. When the number of wire mesh layers was doubled, the ultimate load was further increased from 33.4 to 57.8%. This research showed that WMEC is a practical and excellent shear-strengthening technique for RC beams. Doi: 10.28991/CEJ-2022-08-06-09 Full Text: PDF
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Gencturk, Bora, and Farshid Hosseini. "Evaluation of reinforced concrete and reinforced engineered cementitious composite (ECC) members and structures using small-scale testing." Canadian Journal of Civil Engineering 42, no. 3 (March 2015): 164–77. http://dx.doi.org/10.1139/cjce-2013-0445.
Повний текст джерелаАнотація:
The behavior of reinforced concrete (RC) and reinforced engineered cementitious composites (ECC) was comparatively investigated at the component and system levels through a small-scale (1/8 scale factor) experimental program. The logistical and financial advantages of small-scale testing were utilized to investigate a range of parameters, including the effect of reinforcement ratio and material properties, on the response of reinforced concrete and reinforced ECC structures. The procedures pertaining to material preparation, specimen construction, and input motion development that were critical for enhancing the similarity between the scales are provided. Engineered cementitious composite mixtures with different cost and sustainability indices were evaluated. Under cyclic loading, the stiffness, strength, ductility, and energy absorption capacity of columns made of different ECC mixtures were found to be 110, 65, 45, and 100% higher, respectively, than those of the RC columns. The system level investigation through hybrid simulation showed that the ECC structures sustain less deformation under earthquake excitation due to high energy absorption capacity of the material. The differences in cost, sustainability, and structural performance of different ECC mixtures suggest that a careful selection of materials is required for optimal performance.
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Zainurrahman, Eko Darma, and Sri Nuryati. "Carbon Fiber Reinforced Polymer Sebagai Perkuatan Lentur pada Balok Beton." BENTANG : Jurnal Teoritis dan Terapan Bidang Rekayasa Sipil 8, no. 1 (January 15, 2020): 20–28. http://dx.doi.org/10.33558/bentang.v8i1.1947.
Повний текст джерелаАнотація:
Concrete Beams can experience a sudden collapse when overload because of its brittle characteristic. The use of Carbon Fiber Reinforced Polymer (CFRP) on concrete beams externally as external confinement is predicted to improve concrete mechanics properties, increase the ductility and capacity of concrete, and the flexural strength of concrete beams. An experimental study on the reinforcement of concrete beams with Carbon Fiber Reinforced Polymer (CFRP) was carried out to estimate the effectiveness of CFRP on concrete structures as a concrete beam flexural reinforcement material. Two types of concrete beams are provided in this study to test the flexural strengthening effect of the externally bound CFRP composite. First type of concrete beam used for testing is a normal concrete beams, whereas the second tested beam, the CFRP was laminated by coating the beams with Fiber. The dimensions of both types are 15cm x15cm with a length of 55cm footing range. Testing result obtained the compressive strength was 23,29 MPa, flexural strength of normal and CRFP concretes were 33,41 Kg/cm2 and 48,07 Kg/cm2 respectively. It was concluded that the use of CRFP at the concrete beam increases flexural strength up to 44% with the ratio of 143 %.
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Zhang, Peng Peng, Wen Da Wang, and Jing Xuan Wang. "Preliminary Study on Post-Fire Behavior of Composite Frame with CFST Columns and Composite Beam." Advanced Materials Research 163-167 (December 2010): 713–16. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.713.
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A 3-D finite element model (FEM) using ABAQUS was introduced in this paper to simulate the post-fire behavior of composite frames with concrete-filled steel tubular (CFST) columns and steel beam with reinforced concrete slab. Accurate thermal and material model, element type, and solution method were assumed in the model considering the temperature effect during the fire. Some composite joint specimen post-fire tests were modeled using the FEM. The results obtained from the FEM were verified against those experimental results. The mechanism of the composite frame was investigated based on the FEM.
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Xiao, Kai Tao, Jia Zheng Li, and Hua Quan Yang. "Study of Crack Resistance Property of Polyvinyl Alcohol Fiber Reinforced Concrete." Advanced Materials Research 287-290 (July 2011): 178–82. http://dx.doi.org/10.4028/www.scientific.net/amr.287-290.178.
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The strength, ultimate tensile value, compressive elastic modulus and drying shrinkage of polyvinyl alcohol fiber reinforced concrete were studied by tests, and its crack resistance property was also studied by plate method and temperature stress testing machine. The test results showed that PVA fiber could improve the tensile strength and ultimate tensile value of concrete, lower its compressive elastic modulus and drying shrinkage, restrain its early plastic shrinkage and drying shrinkage cracks, reduce its cracking temperature and improve the crack resistance property of concrete, moreover, the effect of long PVA fiber was better.
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Bodnárová, Lenka, Jitka Peterková, Jiri Zach, and Iveta Nováková. "Study of Heat Transport in Structure of Concrete." Advanced Materials Research 1000 (August 2014): 302–5. http://dx.doi.org/10.4028/www.scientific.net/amr.1000.302.
Повний текст джерелаАнотація:
Current trend of construction of ring roads in large cities going often underground emphasizes safety of implementation and using of such constructions, which is closely connected to possible risks of a fire in these predominantly monolithic structures made from steel reinforced concrete. The paper gives results of the research focused on thermally-technical properties of cement based composite materials resistant to high temperature suitable for application in places with higher risk of fire, like secondary lining of tunnels or underground car parks. The aim was verification of appropriateness of testing mix-designs for application in structures possibly endangered by fire.
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Shilov, Alexandr, Petr Polskoy, Dmitriy Mailyan, and Petr Shilov. "Initial crack effect on the strength of oblique cross sections of reinforced concrete beams strengthened with carbon fiber." E3S Web of Conferences 110 (2019): 01053. http://dx.doi.org/10.1051/e3sconf/201911001053.
Повний текст джерелаАнотація:
In the theory of reinforced concrete, the issue on strength of the oblique beam sections is more complicated than that on the standard sections, since it depends on many factors. The change of at least one of them leads to a significant change in the carrying capacity and in the structural damage pattern. This is due to the fact that at the operating level of the load, all conventional reinforced concrete structures work with cracks, which must be considered in the calculation. However, in the existing regulatory documents and public sources, this issue is not specified. This paper considers the effect of initial cracks on the strength of oblique cross sections of the reinforced concrete beams strengthened with carbon fiber. The experimental studies results obtained through the transverse force testing of forty-two prototypes made of heavy concrete of B30 design grade are presented. The test samples had initial oblique cracks of 0.6-0.9 mm width and were reinforced with three composite U stirrups from the fabric based on unidirectional carbon fibers in the shear span. Initial cracks in the beams were formed at three values of the shear span – 1.5h0, 2h0 and 2.5h0. The test data show the impact of initial cracks on the efficiency of composite reinforcement of oblique cross sections of the prototypes at various values of shear spans.
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Ahmed Arain, Fahad, Masroor Ali Jatoi, Muhammad Saleem Raza, Fahad Ali Shaikh, Farhan Khowaja, and Kunal Rai. "Preliminary Investigation on Properties of Novel Sustainable Composite: Fish Scales Reinforced Cement Concrete." Jurnal Kejuruteraan 34, no. 2 (March 30, 2022): 309–15. http://dx.doi.org/10.17576/jkukm-2022-34(2)-14.
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This study focused on analysing the effect of fish scales reinforcement on fresh and hardened-state properties of concrete. For this purpose, 24 cubes and 24 cylinders were casted at a design mix ratio of 1:2.3:4.3. The water-cement ratio of 0.57 was maintained. The fish scales reinforcement levels of 0%, 1%, 1.5% and 2% by weight of cement were maintained for casting of specimens. For fresh-state assessment, the workability of concrete mixes was observed by slump test and the results showed that, with the addition of fish scales, the slump value decreased due to increase in water demand. With the addition of 2% Fish Scales, the workability of concrete mixes reduced by 36.40%. The compressive strength and tensile strength of concrete cubes and cylinders were tested with Universal Testing Machine (UTM) at curing period of 7 and 28 days. Out of 48 specimens casted, a total of 24 specimens were subjected to compressive strength test while other 24 specimens were tested for tensile strength. The results reported that with addition of 2% fish scales in concrete, the tensile strength of concrete increased but the compressive strength initially decreased and later increased. It can thus be concluded that the fish scales can be incorporated in concrete with steel to enhance the tensile strength of concrete. Keeping the initial decrease in compressive strength of concrete in consideration, it can be recommended that the fish scale reinforced concrete can be safely used in light weight structures and non-structural elements like floor slabs and ribs.
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Maaroof, Atyaf Abdul Azeez, Jasim Ali Abdullah, and Suhaib Yahya Kasim. "Performance of Steel Perforated and Partially-Encased Composite Self-Connected Beams." Jurnal Kejuruteraan 34, no. 4 (July 30, 2022): 703–17. http://dx.doi.org/10.17576/jkukm-2022-34(4)-18.
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The self-connected partially encased composite beams may be used rather than the conventional composite beams; those are connected by the concrete passing through the web-openings of the perforated profiles which works as shear connectors. This technique minimizes the construction cost and enhances the load carrying capacity and ductility of this kind of structures better than the perforated steel beams. The presented work investigates the performance of perforated steel and partially-encased composited self-connected simply supported beams applied to three-points of loading. The effect of the openings shape and the presence of concrete on the performance of the beams are investigated by testing eight specimens of perforated steel and composite beams. The openings’ shapes of perforated steel profiles and composite beams were square, rectangular and circular. The solid steel profiles are taken as control beams in both exposed and encased specimens. The composite beam constructed using perforated steel profile with square openings was reinforced with conventional reinforcement, and setting its stirrups passing through the openings to improve the self connection. The failure modes, strain behaviours, and load-deflection curves were extensively discussed. The composite beams reinforced with perforated steel profiles exhibit higher composite performance than that reinforced with solid profiles. The concrete encasement improved the local deformation performance of the perforated steel profiles (50-300%), leading to a more ductile behaviour and a higher dissipation of energy. The square openings provide higher connectivity than other shapes due to the better arrangement of openings and presence of reinforced concrete.
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Rashid, Muhammad Harunur, Md Maruf Molla, and Imam Muhammad Taki. "Effect of Elevated Temperature on Bond Strength of Concrete." Materials Science Forum 972 (October 2019): 26–33. http://dx.doi.org/10.4028/www.scientific.net/msf.972.26.
Повний текст джерелаАнотація:
In the case of exposure of reinforced concrete structure to accidental fire, an assessment of its residual capacity is needed. Bond strength of concrete was observed under elevated temperatures (150°, 250°, 350° and 500°C) in this study. Cylindrical specimens were prepared for pull-out tests to find out the bond behavior and to observe the mechanical properties of concrete. All the specimens were 100 mm diameter and 200 mm height. The pull-out specimens contain a 10 mm steel bar at its center. The specimens were tested at 52 days age following a 28 days water curing. Samples were preheated for 3 hours at 100°C temperature and then put into the furnace for 1 hour at the target temperature. Samples were tested before preheating as controlled specimens. In case of mechanical properties and the bond strength of concrete, there were no remarkable changes due to elevated temperature up to 150°C. However, the mechanical properties and bond strength were decreased gradually after 150°C temperature. Maximum reduction of bond strength observed was 52.13% and 49.8% at 500°C for testing within 1 hour and after 24 hours of heating respectively when compared to the controlled specimens. Bond strength was found to reduce at a greater rate than compressive strength due to the elevated temperature.
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Huang, Li, Zhuo Qiu Li, and Xian Hui Song. "A Nondestructive Testing Method for Crack in Carbon Fiber Reinforced Concrete with Infrared Thermography." Key Engineering Materials 297-300 (November 2005): 2128–33. http://dx.doi.org/10.4028/www.scientific.net/kem.297-300.2128.
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Based on the functional characteristics of carbon fiber reinforced concrete (CFRC), an improved infrared nondestructive testing method, to detect crack in CFRC by using infrared thermography, is presented in this paper. The principle is that when a CFRC specimen is applied a low voltage, crack existing in the specimen will result in non-homogeneous surface temperature distribution due to the electro-thermal effect of the material. Monitoring the temperature difference on the surface, the crack under the observed surface can be inspected by using infrared thermography. In theory, the mechanism causing the temperature difference comes down to an unsteady heat transfer problem with internal energy sources. In the case of the thermo-physical property of CFRC as given, the sensitivity of this method to the depth of the crack is analyzed by numerical computation.
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Lee, Cheong Cheon, and Akira Shimamoto. "Control Effect on Fatigue Crack Propagation of TiNi Fiber Reinforced / Polycarbonate Composite Material." Key Engineering Materials 261-263 (April 2004): 1085–90. http://dx.doi.org/10.4028/www.scientific.net/kem.261-263.1085.
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In this paper, the TiNi fiber reinforced / PC composite material was developed, and then control of the fatigue crack growth due to the shape memory effect was studied. Enhancement of mechanical properties and resistance of deformation of the TiNi fiber reinforced / PC composite were investigated by fatigue experiments. The fatigue behavior and crack propagation were in-situ observed with a SEM servo-pulser (fatigue testing instrument with scanning electron microscope) while increasing temperature. As the results, the fatigue life was improved, and the effectiveness of fatigue resistance was confirmed. The shape memory effect and expansion behavior of the matrix caused by temperature increasing examined the effect of the fatigue crack propagation control. It was verified that the control of fatigue crack growth is attributed to the compressive stress field in the matrix due to shrinkage of the TiNi fibers above austenitic finishing temperature (Af).
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Shimamoto, Akira, Yasubumi Furuya, and Hiroyuki Abe. "Effect of Fatigue Crack Propagation in the Shape Memory Alloy Fiber Reinforced Smart Composite." Key Engineering Materials 334-335 (March 2007): 1093–96. http://dx.doi.org/10.4028/www.scientific.net/kem.334-335.1093.
Повний текст джерелаАнотація:
In this paper, the TiNi fiber reinforced / Polycarbonate(PC) composite material is developed, and its properties is studied. Conducting fatigue experiments, shape memory effect of the material for preventing fatigue crack growth are investigated. The fatigue behavior and crack propagation are observed under increasing temperature with a SEM servo-pulser, which is a fatigue testing instrument with scanning electron microscope. As the results, the effectiveness of fatigue resistance is confirmed. The shape memory effect and expansion behavior of the matrix caused by increasing temperature create the effect of the fatigue crack propagation control. It is verified that the controlling of fatigue crack growth is attributed to the compressive stress field in the matrix which is caused by shrinkage of the TiNi fibers above austenitic finishing temperature (Af).
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Serafini, Ramoel, Felipe Pereira Santos, Ronney Rodrigues Agra, Albert De la Fuente, and Antonio Domingues de Figueiredo. "EFFECT OF SPECIMEN SHAPE ON THE COMPRESSIVE PARAMETERS OF STEEL FIBER REINFORCED CONCRETE AFTER TEMPERATURE EXPOSURE." Journal of Urban Technology and Sustainability 1, no. 1 (December 11, 2018): 10–20. http://dx.doi.org/10.47842/juts.v1i1.7.
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This study investigated the effect of specimen shape (cylindrical and cubical) on the compressive strength and elastic modulus of steel fiber reinforced concrete after exposure to the temperatures of 150, 300, 450, and 600 °C. Results show that the compressive strength and elastic modulus of the composite significantly reduce with the increase in temperature, independent of the specimen shape. Additionally, a significant difference in the compressive strength and elastic modulus conversion factors for cube-cylinder was verified with the increase in temperature. This study contributes to the limited amount of studies regarding the effect of elevated temperatures on steel fiber reinforced concretes and shows that the elevated temperatures may have a significant effect in the conversion factors for cube-cylinder.
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Xu, Xun Qian, Wei Yang, Hong Liang Xiang, Jian Bo Wang, and Xiao Yang. "Effect of Crack Initiation and Life Prediction of Polyacrylonitrile-Reinforced Gussasphalt Surfacing over Steel Bridge Deck under Fiber Content Variation." Crystals 10, no. 3 (February 28, 2020): 155. http://dx.doi.org/10.3390/cryst10030155.
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The crack initiation and life prediction of fiber-reinforced asphalt concrete (FRAC) surfacing for steel bridge decks under a cyclic vehicle load are analyzed from the perspective of damage mechanics. The damage field and the stress and strain field evolution rule of a composite beam in fatigue test are studied, and a fatigue failure criterion is proposed for steel deck FRAC surfacing. Bending fatigue tests are performed on composite beams composed of a steel deck and polyacrylonitrile (PAN)-fiber-reinforced Gussasphalt (GA), i.e., GA-PAN, concrete surfacing under different fiber content and temperature conditions. The damage evolution characteristics of GA-PAN concrete surfacing over the steel deck with different fiber lengths and volume ratios are predicted by analyzing the fatigue life equations. The results show that the steel bridge deck FRAC surfacing model can reflect the comprehensive influence of the fiber content and length on the fatigue performance of steel bridge AC. Specifically, a lower temperature results in the fiber more synergistically affecting the fatigue resistance of AC. Theoretically, the service performance of asphalt concrete increases with the increase of fiber length and content. The optimum fiber length and volume ratio of GA-PAN are found to be 9 mm and 0.46–0.48%, respectively, considering the construction workability.
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Benmokrane, Brahim, Ehab El-Salakawy, Amr El-Ragaby, and Sherif El-Gamal. "Performance evaluation of innovative concrete bridge deck slabs reinforced with fibre-reinforced-polymer bars." Canadian Journal of Civil Engineering 34, no. 3 (March 1, 2007): 298–310. http://dx.doi.org/10.1139/l06-173.
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This paper presents the construction details, field testing, and analytical results of six innovative concrete bridges reinforced with fibre-reinforced-polymer (FRP) bars recently constructed in North America, namely Wotton, Magog, Cookshire-Eaton, Val-Alain, and Melbourne bridges in Quebec, Canada, and Morristown bridge in Vermont, USA. All six bridges are girder type, with main girders made of either steel or prestressed concrete. The main girders are supported over spans ranging from 26.2 to 50.0 m. The deck is a 200–230 mm thick concrete slab continuous over spans of 2.30–3.15 m. Different types of glass- and carbon-FRP reinforcing bars and conventional steel were used as reinforcement for the concrete deck slab. The six bridges are located on different highway categories, which means different traffic volume and environmental conditions. The bridges are well instrumented at critical locations for internal temperature and strain data collection using fibre optic sensors. These sensors are used to monitor the deck behaviour from the time of construction to several years after the completion of construction. The bridges were tested for service performance using calibrated truckloads. In parallel, a finite element analysis (FEA) was conducted and verified against the results of the field load tests. The FEA was then used to run parametric studies to investigate the effect of several important parameters such as FRP reinforcement type and ratio on the service and ultimate behaviour of these bridge decks. The analytical and field results under real service conditions, in terms of deflections, cracking, and strains in reinforcement and concrete, were comparable to those of concrete bridge deck slabs reinforced with steel.Key words: bridges deck slabs, fibre-reinforced-polymer (FRP) bars, field testing, finite element analysis.
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Berestianskaya, Svitlana, Evgeniy Galagurya, Olena Opanasenko, Anastasiia Berestianskaya, and Ihor Bychenok. "Experimental Studies of Fiber-Reinforced Concrete Prisms Exposed to High Temperatures." Key Engineering Materials 864 (September 2020): 3–8. http://dx.doi.org/10.4028/www.scientific.net/kem.864.3.
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Fiber-reinforced concretes are varieties of composite materials. Such materials are commonly used nowadays. Concrete is fiber-reinforced using various fibrous materials, or fibers, which are evenly distributed over the volume of the concrete matrix and simultaneously provide its 3D reinforcement. Fiber-reinforced concrete has better stress-related strength characteristics than ordinary concrete. Since building structures must meet both the strength, rigidity and stability requirements, and the fire safety requirements, then for the extensive use of fiber-reinforced concrete structures, not only the external load design, but also temperature effect design should be conducted in the design phase. The strength and strain characteristics of fiber concrete exposed to high temperatures must be known for this purpose. In view of this, three series of prisms were manufactured and tested: the first series contained no fiber at all (control prisms), the second series contained basalt fiber, and the third series contained steel fiber. The test results showed that adding fibers improves the mechanical characteristics of fiber-reinforced concrete samples under specified conditions.
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Kalamkarov, Alexander L., Anastasis V. Georgiades, Douglas O. MacDonald, and Stephen B. Fitzgerald. "Pultruded fibre reinforced polymer reinforcements with embedded fibre optic sensors." Canadian Journal of Civil Engineering 27, no. 5 (October 1, 2000): 972–84. http://dx.doi.org/10.1139/l00-034.
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The use of the pultrusion process for the manufacture of fibre reinforced polymer (FRP) composites with embedded fibre optic sensors is discussed. The specific application is the use of smart composite reinforcements for strain monitoring in innovative concrete bridges and structures. The Bragg grating and Fabry-Perot fibre optic sensors are embedded during the pultrusion of FRP rods and the process-induced residual strains are evaluated using these sensors. The behaviour of optic sensors during pultrusion is assessed, and the effect of the embeddment of optical fibres and their surface coatings on the mechanical properties of the composite material is investigated. To verify the operation of the optic sensors embedded in the smart pultruded rods, mechanical tests were conducted and the output of the fibre optic sensors was compared to that of an extensometer. These mechanical tests were performed at room temperature as well as under conditions of low and high temperature extremes. The reliability assessment of the fibre optic sensors further entailed the study of their fatigue and creep behaviour as well as their performance when the rods in which they are embedded are placed in a severe environment (e.g., alkaline solutions) that may simulate conditions encountered in concrete structures wherein the composite rods will be used as prestressing tendons or rebars.Key words: smart composite reinforcements, fibre optic sensors, pultrusion, residual strain, fatigue and creep behaviour, reliability assessment.
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Won, Moon. "Improvements of Testing Procedures for Concrete Coefficient of Thermal Expansion." Transportation Research Record: Journal of the Transportation Research Board 1919, no. 1 (January 2005): 23–28. http://dx.doi.org/10.1177/0361198105191900103.
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The coefficient of thermal expansion (CTE) of concrete has a significant effect on the performance of portland cement concrete pavement. Concrete with a higher CTE is more prone to cracking, additional warping, and spalling. To improve PCC pavement performance, several districts of the Texas Department of Transportation (TxDOT) currently limit the CTE of concrete. To support this policy, efforts have been made to improve the accuracy and repeatability of the testing procedures for CTE. The current AASHTO Test Method TP 60 has been evaluated, its shortcomings identified, and improvements made. The improvements include CTE determination from regression analysis of temperature and displacement measurements. The effects of a number of variables on concrete CTE were investigated. The effect of the rate of heating and cooling is negligible. Concrete age and specimen size also have a negligible effect. Coarse aggregate content in the concrete mix has an effect on the test results. This test procedure was used to evaluate coarse aggregates from 32 sources in Texas. The results show that coarse aggregate type has a significant effect on concrete CTE. The proposed testing procedure for concrete CTE provided more accurate results than the AASHTO TP 60. TxDOT plans to implement this test procedure and to develop appropriate steel design standards for continuously reinforced concrete pavement and other construction-related requirements such as different curing methods for concrete with varying CTEs. This implementation should result in better concrete pavement performance.
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Fu, Hao, Yang Dong Ou, Wei Ting Xu, and Lin Jie Kong. "The Experimental Study of Using Composite Polymer Fiber in Concrete." Advanced Materials Research 785-786 (September 2013): 257–63. http://dx.doi.org/10.4028/www.scientific.net/amr.785-786.257.
Повний текст джерелаАнотація:
Using the cylinder to take 2L as sample from five equidistant azimuthally and the center point to weight. Wash away the cement slurry in sample thoroughly first. Put the rest into the container full with water and churn. Then, collect the suspended fiber using the square-hole sieve of 75 um aperture. Churn it as more as possible to make sure of collecting whole fiber in samples. Wash clear and dry under 105±5 Celsius degree to constant weight. After cooling to room temperature then weight them respectively and accurate to 0.01g. The dispersion performance will be qualified if the dispersion relative error between arithmetic average value of synthetic fiber content and theoretical calculated value is from -10% to 10%. The concrete test steps is as per “Cement Concrete and Mortar Synthetic Fiber GBT21120-2007”. Slump、slump flow of all the fresh concrete were tested to determine the fresh properties of fiber reinforced concrete. The mixing proportions are listed in Table 1, All the strength tests were carried out following the Chinese standard GB/T 50081-2002. Resistance to chloride ion penetration was measured according to ASTM C1202 (Rapid determination of the Chloride Permeability of Concrete) at the curing age of 7d、28 days using a proportion of the Φ100mm × 50mm cylinders. The early crack resistance test is according to the fiber reinforced concrete testing standards CECS 13-2009. It can be concluded that the working performance of composite fiber concrete are better compared with the single mixed concrete. It is obvious that the spread degree is being larger as the increasing of cellulosic fiber based on the certain adulterate amount. Fiber incorporation has little influence on concrete 7 d 、28 d age compression strength. The 7d and 28d splitting tensile strength、flexural strength were enhanced by incorporation of fibers. The addition of fiber improved the resistance ability of 7d and 28d fiber concrete chloride penetration to a great extent. It improved the ability of corruption resistance from seawater and extended the life of concrete and hence promoting the wide spread usage in marine project. Fiber incorporation delayed the occurrence of early crack and controlled the development of cracks, which made the concrete plastic shrinkage crack width and the maximum crack areas reduced.
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Krzywon, Rafał, and Janusz Brol. "Glass transition effect of adhesive in timber beams strengthened with CFRP overlays." MATEC Web of Conferences 262 (2019): 03001. http://dx.doi.org/10.1051/matecconf/201926203001.
Повний текст джерелаАнотація:
There are situations when timber structure requires strengthening caused by environmental deterioration or changes in load conditions. Its mechanical performance can be increased by use of externally bonded high strength fibre reinforced composite (FRP). The place of application increases the sensitivity of this technique to environmental effects, including heating by the sun rays. Surface temperature can exceed 70 °C, while usually as safe is considered 45 °C. Paper describes the tests of timber beams strengthened with two types of composites: unidirectional CFRP sheet and CFRP strip. They were heated at various temperature ranges and tested in bending. Out of the nine tested beams, only one heated to 95 °C was not damaged by the delamination of the composite overlay, remaining beams have not been destroyed due to achieved deflection exceeding the press cylinder range or were failed due to rupture of carbon fibres. The influence of the temperature was better recognizable in differences of deflections and strains caused by the creep in the adhesive layer weakened by temperature. It should also be emphasized that got results are much better than for commonly tested reinforced concrete beams, where delamination caused failure slightly above 65 °C.
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Lee, Cheong Cheon, and Akira Shimamoto. "Control Effect on Fatigue Crack Propagation of TiNi Fiber Reinforced PMMA Composites." Key Engineering Materials 297-300 (November 2005): 2929–0. http://dx.doi.org/10.4028/www.scientific.net/kem.297-300.2929.
Повний текст джерелаАнотація:
In this paper, the TiNi fiber reinforced/PMMA (Poly methyl methacrylate) composite is developed, and its effectiveness of controlling fatigue crack growth is studied. The TiNi fiber reinforced/PMMA composite’s mechanical property enhancement and deformation resistance are also studied. The fatigue behavior and crack propagation are observed with a SEM servo-pulser (fatigue testing instrument with scanning electron microscope) while increasing temperature. As the results, it is confirmed that the fatigue life and resistance are improved. How the shape memory effect and expansion behavior of the matrix caused by temperature increasing affect the fatigue crack propagation control is examined. It is verified that the control of fatigue crack growth is attributed to the compressive stress field in the matrix due to shrinkage of the TiNi fibers above austenitic finishing temperature (Af).
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Čechmánek, René, Vladan Prachař, and Jiří Loskot. "Filler from Expanded Glass as a Light-Weighing Component of the Cement Composite with Fiber Reinforcement." Advanced Materials Research 1000 (August 2014): 102–5. http://dx.doi.org/10.4028/www.scientific.net/amr.1000.102.
Повний текст джерелаАнотація:
Bulk density reduction of the cement composite is possible by the means of using suitable light fillers in a matrix or porous structure creation with an air-entraining agent. Both ways are more or less suitable or effective for proper parameter achievement. From the range of possible fillers with different material properties and influence on rheological parameters during production granulated expanded glass worked the best. By the means of laboratory testing an effect of two fillers based on expanded glass on the fiber reinforced cement composite was verified. Practical applicability was tested in the production of commonly manufactured glass fiber reinforced concrete elements, such as channels for electrical cable deposition and products for urban equipment.
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Choi, Pangil, Dong-Ho Kim, Bong-Hak Lee, and Moon C. Won. "Evaluation of structural responses of continuously reinforced concrete pavement (CRCP) using falling weight deflectometer." Canadian Journal of Civil Engineering 43, no. 1 (January 2016): 28–39. http://dx.doi.org/10.1139/cjce-2015-0263.
Повний текст джерелаАнотація:
The objective of this study is to suggest reasonable structural evaluation method of continuously reinforced concrete pavement (CRCP) using falling weight deflectometer (FWD). The effects of transverse crack spacing and temperature conditions were investigated in CRCP sections with various slab thicknesses and pavement ages. A total of 20 CRCP sections were selected throughout Texas and structural responses were evaluated from 2006 to 2013 for 8 testing years. Test results show that transverse crack spacing has little effect on deflection and load transfer efficiency (LTE). The LTE values were maintained at above 90%, regardless of crack spacing, temperature condition or pavement age. Temperature variations had small effects on deflections at cracks and the mid-slab, but almost no effects on LTE. Maximum deflections and back-calculated k-values appear to be better indicators of structural condition of CRCP than LTE. Load transfer efficiency is not the best indicator of structural condition of transverse cracks in CRCP. Deficiencies in slab support are the primary cause of full-depth distresses in Texas, and back-calculated k-values, which combine both a maximum deflection and the shape of deflection bowl from FWD testing, may be a better indicator of the structural condition of CRCP.
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Patel, Himanshu V., and Harshit K. Dave. "The effect of stacking sequence and fiber orientation on tensile and flexural strength of fiber reinforced composite fabricated by VARTM process." Engineering Solid Mechanics 11, no. 1 (2023): 47–62. http://dx.doi.org/10.5267/j.esm.2022.9.001.
Повний текст джерелаАнотація:
In this study, Carbon, Glass, and Aramid fiber reinforced composite and their hybridized forms were fabricated using five different stacking sequences of the fabrics. Using the Vacuum Assisted Resin Transfer Molding (VARTM) procedure, epoxy resin was injected into these fabrics and allowed to cure at room temperature. From these five stacking sequences, a standard specimen with four different orientations viz. 0/90°, 15/75°, 30/60°, 45/-45° orientations were obtained using the Abrasive Water Jet Machining(AWJM) Process. The influence of stacking order and fiber orientation on tensile and flexural properties of composite was investigated. From the result of tensile testing, the highest and lowest tensile strength values were observed for neat carbon fiber reinforced composite at 0/90° orientation and at 45/-45° orientation respectively. The highest flexural strength was achieved in a hybrid combination of two layers of carbon, glass and aramid fabric for 0/90° whereas the lowest flexural strength was found in glass reinforced composite for the 45/-45° orientation.
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Ali Salih, Yaseen, Mohammed Faeq Yass, Ahmed Shihab Ahmed, and Aziz I. Abdulla. "Effect of Adding Porcelain and Glass Powder Mixture on Epoxy Properties." International Journal of Engineering & Technology 7, no. 4.37 (December 13, 2018): 39. http://dx.doi.org/10.14419/ijet.v7i4.37.23612.
Повний текст джерелаАнотація:
In this research, porcelain powder and glass was added by 0.25% (0.15% porcelain powder and 0.1% glass powder) to the epoxy used in the concrete strengthening. The addition improved epoxy properties and reduced the cost. The results showed that the addition of porcelain and glass powder decrease the interaction temperature by 11.37%, epoxy flow by 10.41%, and increase the compressive strength by 7.61%. Upon testing the improved epoxy cubes under the effect of temperatures up to 200ᵒ C compression resistance decreased by 6.36%, while both modulus of rupture and modulus of elasticity improved by (1.03% and 4.11%) respectively. The epoxy was tested and used to strengthen reinforced concrete beams and tests showed good improvement in flexural properties.
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Ding, Zhu, Can Lu, Peng Cui, and Wei Ting Xu. "Primal Study on Mechanical Properties of Phosphate Based Geopolymer." Key Engineering Materials 726 (January 2017): 490–94. http://dx.doi.org/10.4028/www.scientific.net/kem.726.490.
Повний текст джерелаАнотація:
A novel inorganic matrix for fiber composites prepared from phosphate based geopolymer (PBG) was synthesized at ambient temperature. The mechanical property of PBG paste and the carbon fiber reinforced PBG composite was determined. Test results showed that the compressive strength of PBG paste at the age of 28 days was found to be 33.67 MPa. Moreover, the carbon fiber sheets enhanced the bending strength and ductility of PBG paste by up to 1300% and 307% respectively. Finally, the strengthening effect of this new composite on concrete beam was evaluated. The carbon fiber PBG composite applied on the bottom surface of concrete beam increased the bending strength by 183%. Therefore, it is concluded that PBG can be a promising inorganic matrix that can be used to strengthen deteriorated concrete structures.