Artykuły w czasopismach na temat „Concrete tensile strength”
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1
Biel, Timothy D., i Hosin Lee. "Magnesium Oxychloride Cement Concrete with Recycled Tire Rubber". Transportation Research Record: Journal of the Transportation Research Board 1561, nr 1 (styczeń 1996): 6–12. http://dx.doi.org/10.1177/0361198196156100102.
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Either portland cement or magnesium oxychloride cement was used as binders for concretes that incorporated fine rubber aggregate, ranging from 0 to 25 percent by volume. The concretes were tested for their compressive and split tensile strengths to determine whether the use of a magnesium oxychloride cement along with recycled tire rubbers would improve concrete properties. Failure of the concrete around the rubber particles was attributed to tension failure, leading to weak shear failure of the concrete matrix. Both portland and magnesium oxychloride cement concretes lost 90 percent of their compressive strength with 25 percent rubber by volume. The portland cement concrete retained 20 percent of its tensile strength, and the magnesium oxychloride cement concrete retained 35 percent of its tensile strength. Both compressive and tensile strengths of magnesium oxychloride cement rubber concrete were significantly higher than rubberized portland cement rubber concrete.
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Windisch, Andor. "The tensile strength: The most fundamental mechanical characteristics of concrete". Concrete Structures 22 (2021): 1–4. http://dx.doi.org/10.32970/cs.2021.1.1.
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Concrete is an inhomogeneous building material. It has a considerable and reliable compressive strength and a relative low tensile strength which can be even exhausted locally under unfortunate conditions. It is quite obvious that the concrete tensile strength was always reprehended as the most unreliable concrete property. A simple relationship between tensile- and compressive strength is introduced. The mechanical background of the relation tensile- to compressive strength in case of ‘normal’ and high strength concretes is elucidated. Mechanical bond, too, relies completely on the tensile strength. In the design of structural concrete members the tension fields are more characteristic than the compression fields. Effective concrete strengths are not successful. Tensile strength can be applied as ‘yield condition’ for the lower bound solution in the theory of plasticity. The paper intends to contribute to the acceptance of the tensile strength as the more fundamental concrete characteristics.
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Liao, Wen-Cheng, Po-Shao Chen, Chung-Wen Hung i Suyash Kishor Wagh. "An Innovative Test Method for Tensile Strength of Concrete by Applying the Strut-and-Tie Methodology". Materials 13, nr 12 (18.06.2020): 2776. http://dx.doi.org/10.3390/ma13122776.
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Tensile strength is one of the important mechanical properties of concrete, but it is difficult to measure accurately due to the brittle nature of concrete in tension. The three widely used test methods for measuring the tensile strength of concrete each have their shortcomings: the direct tension test equipment is not easy to set up, particularly for alignment, and there are no standard test specifications; the tensile strengths obtained from the test method of splitting tensile strength (American Society for Testing and Materials, ASTM C496) and that of flexural strength of concrete (ASTM C78) are significantly different from the actual tensile strength owing to mechanisms of methodologies and test setup. The objective of this research is to develop a new concrete tensile strength test method that is easy to conduct and the result is close to the direct tension strength. By applying the strut-and-tie concept and modifying the experimental design of the ASTM C78, a new concrete tensile strength test method is proposed. The test results show that the concrete tensile strength obtained by this proposed method is close to the value obtained from the direct tension test for concrete with compressive strengths from 25 to 55 MPa. It shows that this innovative test method, which is precise and easy to conduct, can be an effective alternative for tensile strength of concrete.
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Saud, Abdullah F., Hakim S. Abdelgader i Ali S. El-Baden. "Compressive and Tensile Strength of Two-Stage Concrete". Advanced Materials Research 893 (luty 2014): 585–92. http://dx.doi.org/10.4028/www.scientific.net/amr.893.585.
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An experimental investigation was conducted to evaluate the compressive, tensile strength and modulus of elasticity of two-stage concrete (TSC) at different water-to-cement ratios. The primary objectives were to measure the elastic modulus, compressive strength and splitting tensile strength of TSC and to determine if there is a quantifiable relationship between compressive and tensile strength. Behavior of TSC in compression has been well documented, but there are little published data on its behavior in tension and modulus of elasticity. This paper presents the experimental results of preplaced, crushed granite aggregate concreted with five different mortar mixture proportions. A total of 48 concrete cylinders were tested in unconfined compression modulus of elasticity and splitting tension at 28 and 90 days. It was found that the modulus of elasticity and splitting tensile strength of two-stage concrete is equivalent or higher than that of conventional concrete at the same compressive strength. Splitting tensile strength can be conservatively estimated using the ACI equation for conventional concrete.
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Li, Rui, Lei Liu, Zhihua Zhang i Huaming An. "Experimental Study of Brazilian Tensile Strength of Concrete Under Static Loads". E3S Web of Conferences 206 (2020): 01018. http://dx.doi.org/10.1051/e3sconf/202020601018.
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Concrete is one of the most significant materials in modern society. It is widely used in many projects. Thus it is essential to study the strength and the failure patterns of this material. As well known, the compressive strength is much higher than the tensile strength for concrete. Thus, it is easy to fail due to the tensile strength for concrete. Thus, this paper focuses on the study of the tensile strength of the concrete and its failure patterns. Three types of concretes are made for studying the tensile strengths and the failure patterns of the concretes. Then the Brazilian tensile strength test method is employed in this study. The mythology of calculating tensile strength by the Brazilian tensile strength test method is introduced. Many discs are made for the tests. The Rock mechanics testing machine is used to excavate pressure on the top and bottom of the disc. It is concluded that the failure of the disc is along the vertical diameter between the top and bottom plates contacting the dis. The tensile failure is not obviously influenced by the ratios of the materials while the tensile strength is significantly influenced by the ratios of the concrete. The damage index of concrete is also proposed to describe the capabilities of resisting failure.
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Khasanov, Bakhridin, Ruzimurat Choriev, Zukhra Ismailova, Guzal Eshchanova i Timur Mirzaev. "Study of the strength properties of modified concrete in tension". E3S Web of Conferences 365 (2023): 02004. http://dx.doi.org/10.1051/e3sconf/202336502004.
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The resistance of concrete to axial tension is much less than the resistance to compression and is largely determined by the adhesion of its components. The low tensile strength of ordinary concrete is explained by the heterogeneity of its structure and the discontinuity of concrete, which contributes to the development of stress concentration, especially under the action of tensile forces. To increase the tensile strength of concrete, it is necessary to eliminate, first of all, the heterogeneity of the structure of concrete - one of the main reasons for the large dispersion of the results of mechanical tests of this material, which affects the experimental determination of compressive strength. A significant difference between the compressive strength for ordinary concrete indicates a rather large spread of such values. This scatter is explained by the different influence of factors on tension and compression. For example, for ordinary concretes, it was found that with an increase in W/C , the tensile strength decreases, but to a lesser extent than the compressive strength. With an increase in the grade of concrete, the tensile strength increases. High-strength concretes, as a rule, prepared on concrete mixes with low W/C and on clean conditioned aggregates in the form of crushed stone and sand, have an increased density, therefore, they have less variation in strength readings both in compression and at stretching [1-4].
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Makrides-Saravanos, Elli, i T. Rezansoff. "The effect of a chloride-based accelerating admixture on the tensile strength of concrete". Canadian Journal of Civil Engineering 12, nr 3 (1.09.1985): 673–84. http://dx.doi.org/10.1139/l85-074.
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Compression and tension tests were performed on specimens made from high-early-strength concrete, where the strength acceleration was achieved by using a chloride-based accelerating admixture. Comparison with specimens made from concrete without the admixture showed that the concrete with the admixture was significantly weaker in tension for equal compressive strength.Curing times ranged from 3 days to 3 or 4 months while compressive strengths ranged from 16 to 37 MPa depending on the batch and the age at testing. Three types of tension tests, the standard split cylinder test, the standard modulus of rupture test, and a pull-out test were used in the study.Current design equations that relate tensile strength of concrete to the measured compressive strength may overestimate the actual tensile strength of high-early-strength concrete where acceleration is achieved through the addition of an admixture. These equations are found in provisions for anchorage, development, and splicing of reinforcement, shear and torsion strength, and the prediction of service load deflections. Key words: concrete, accelerated strength, tensile strength, admixtures, curing, splitting tensile strength, modulus of rupture, strength correlations.
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He, Xi Xi, i Ping Fang. "Influence of Concrete Strength Grade and Age on Three Tensile Strengths". Advanced Materials Research 450-451 (styczeń 2012): 179–86. http://dx.doi.org/10.4028/www.scientific.net/amr.450-451.179.
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Uniaxial tensile strength is one of the important strength parameters of concrete. In this study, two test methods were applied to determine direct tensile strength, splitting tensile strength and flexural strength of fly ash concrete specimens with the same cross section and different strength grades. Relationship among the uniaxial tensile, splitting tensile and flexural strength of concrete were researched. Furthermore, the influence of concrete strength and age to the three tensile strengths were specifically analyzed in the paper.
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Vodička, Jan, Vladimír Křístek i Václav Ráček. "Strength Classes of Concrete versus Strength Classes of Fibre Concrete". Solid State Phenomena 249 (kwiecień 2016): 112–18. http://dx.doi.org/10.4028/www.scientific.net/ssp.249.112.
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Basic characteristics of each produced concrete and fibre reinforced concrete are characterized by the compression strength recorded by the standard sets of tests performed on cylinders and cubes. In addition, for the fibre reinforced concrete, the characteristic tensile strength at formation of microcracks and cracks of standard widths is required. Proofs of the referred characteristic tensile strength should be carried out also by the destructive tests on standard specimens including the methodology provided for their implementation.The rapid development of fibre reinforced concrete, accelerated by manufacturers of fibres and their interest to apply the fibre reinforced concrete in structural practice from where the beneficial effects of the tensile strength can be obtained, resulted in conclusion that there is currently no uniform methodology for evaluation of the tensile strength. Tensile strength studies are performed, for example, according to National standardization Committees and research institutes.At present, the two very different methodologies can be applied to test tensile characteristics of fibre reinforced concrete - MODEL CODE and the Czech national standard – ČSN P 73 2452. The results of the destructive tests, obtained in accordance with the mentioned methodologies are so different that the same strength class for the tested fibre reinforced concrete is not possible to be defined.The paper proves the diversity of methodologies to perform destructive testing, by which it is possible to obtain the tensile characteristics of fibre reinforced concrete needed to define the same strength class. Procedures for evaluation of tensile characteristics from results of destructive tests are also assessed. Significance of the obtained strengths from the point of view of objectivity for the practical application of the fibre concrete in the load-carrying structures are discussed.
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Blazy, Julia, Łukasz Drobiec i Paweł Wolka. "Flexural Tensile Strength of Concrete with Synthetic Fibers". Materials 14, nr 16 (7.08.2021): 4428. http://dx.doi.org/10.3390/ma14164428.
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Fiber reinforcement is currently most often used in floors, railway sleepers, prefabricated structural elements such as slabs, beams and tanks, and in small architecture elements. Designing elements or structures made of fiber-reinforced concrete requires knowledge of its basic mechanical parameters. In the case of concretes with metallic fibers, the literature can find many tests and standard guidelines regarding compressive, flexural, tensile strength and fracture energy. The properties of concretes with non-metallic fibers are slightly less recognized, especially concretes with new types of polymer fibers. Additionally, the lack of standardized methods of testing concrete with polymer fibers make their application much more difficult. In the article, the possibility of using the EN 14651 standard to assess the flexural tensile strength of concrete with the addition of 2.0 and 3.0 kg/m3 of synthetic fibers with different geometry and form was presented. There was a 5.5–13.5% increase in the flexural tensile strength depending on the mixture type. Moreover, in the case of fiber-reinforced concretes, the ductility was enhanced and the samples were characterized by significant residual flexural tensile strengths. Additionally, from the workability tests it was concluded that after the incorporation of fibers, the consistency class decreased by one, two or three. Nevertheless, the compressive strengths of concrete with and without fibers were very similar to each other, and varied from 58.05 to 61.31 MPa. Moreover, it was concluded that results obtained from three-point bending tests significantly differed from empirical formulas for the calculation of the flexural tensile strength of fiber-reinforced concretes with dispersed steel fibers present in the literature. As a result, the new formula determined by the authors was proposed for concrete with polymer fibers with a nominal fiber content ≤1.0% and slenderness of up to 200. It must be mentioned that the formula gave a very good agreement with studies presented in different literature positions. In addition, an attempt was made to evaluate the strengths of tested mixes in accordance with the Model Code 2010. However, it occurred that the proposed fiber-reinforced concrete mixtures would not be able to replace traditional reinforcement in a form of steel bars. Furthermore, in uniaxial tensile tests, it was not possible to determine the σ–w graphs, and received results for maximum tensile strength did not show the clear influence of fibers incorporation on concrete. Then, the fracture energy enhancement (from about 16 to 22 times) and dependencies: crack mouth opening displacement–deflection; crack mouth opening displacement–crack tip opening displacement; and crack tip opening displacement–deflection were analyzed. Finally, the results from flexural tensile tests were compared with measurements of the surface displacement field obtained through the Digital Image Correlation technique. It was concluded that this technique can be successfully used to determine the crack mouth and crack tip opening displacements with very high accuracy.
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Závacký, Martin. "A COMPARISON OF TESTING METHODS FOR DETERMINATION OF SPRAYED CONCRETE TENSILE STRENGTH". Acta Polytechnica CTU Proceedings 23 (30.07.2019): 54–57. http://dx.doi.org/10.14311/app.2019.23.0054.
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Sprayed concrete is important construction material in tunnelling. Primary lining is essential in NATM where the sprayed concrete can be loaded by tension due to bending moments. The tension is common reason of failure because concrete has a relatively low tensile strength. The tensile strength is usually determined by splitting tensile test in laboratory. However, the results can be distorted because the specimen is not loaded by pure tension in this case. The paper compares results of concrete tensile strength determined by two methods: indirect by the splitting tensile test and direct by the modified tensile test.
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Hadi, Faizal, i Agustin Gunawan. "PENGARUH LAMA PENGERINGAN BETON SERAT PANDAN PUNDAK DURI (PANDANUS TECTORIUS) TERHADAP KUAT TARIK BELAH BETON". Inersia, Jurnal Teknik Sipil 11, nr 1 (14.09.2019): 1–6. http://dx.doi.org/10.33369/ijts.11.1.1-6.
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Concrete is a material that have the strength to compression, but it is weak against tensile strength. The weakness of the tensile strength of concrete can be minimized by adding pandanus tectorius fiber. This study was aimed to determine the effect of adding pandanus tectorius fiber to split- tensile strength of concrete and percentage of the fiber in concrete that shows the highest split- tensile strength. The specimens used in this study is cylindrical with dimensions of 30 cm in height and 15 cm in diameter (SNI 03-4810-1998). Total of specimens is 32 that consist of 8 normal concretes and 24 variation concretes. An addition of pandanus tectorius fiber with the variation of 0,25%, 0,5%, and 0,75% was based on volume of the specimen. The mix design of concrete used water-cement ratio of 0.5 and slump of 60-100 mm. The splittensile strength of concrete was tested at 7 days and 14 days of dryng after immersing for 27 days. The result of split-tensile strength test of concrete with a variation of pandanus tectorius fiber showed a decreasing. The decreasing of split-tensile strength of concrete at 41 days was smaller than at 34 days to normal concrete. The highest decreasing percentage of split-tensile strength of variation concrete to normal concrete was respectively 9,249% (variation 0,25 tested at 41 days) and 14,518% (variation 0,75% tested at 34 days) .
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Malagavelli, Venu, i Neelakanteswara Rao Paturu. "Polyester Fibers in the Concrete an Experimental Investigation". Advanced Materials Research 261-263 (maj 2011): 125–29. http://dx.doi.org/10.4028/www.scientific.net/amr.261-263.125.
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Construction field has experienced a growing interest in Fiber Reinforced Concrete (FRC) due to its various advantages. The disposal of industrial waste especially non biodegradable waste is creating a lot of problems in the environment. In the present investigation, an attempt has been made by using non biodegradable waste (polyester fibers) in the concrete to improve the crack resistance and strength. Concrete having compressive strength of 25MPa is used for this study. Samples were prepared by using various fiber contents starting from 0 to 6% of with an increment of 0.5% for finding Compressive strength, split tensile strength and flexural strengths. It is observed that, compressive strength, split tensile strength and flexural strengths of concretes is increasing as the fiber content is increased up to some extent.
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Wang, Xing Guo, Zhao Xia Cheng, Yongchao Hao i Yi Xin Wang. "Experimental Behavior of Reinforced Shotcrete with Low Fiber Content". Advanced Materials Research 168-170 (grudzień 2010): 1976–80. http://dx.doi.org/10.4028/www.scientific.net/amr.168-170.1976.
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Mixing three different fiber composites into concrete specimens respectively, compressive strength, splitting tensile strength and flexural strength for fiber-reinforced concrete was done. The results show that the strengths of fiber reinforced concrete are improved to some extent. Due to the addition of fiber, the fiber concrete bears some of the force in tension, thus the time from the initial crack to damage is more prolonged comparing with normal concrete. Fiber concrete specimens did not get the collapse and lower intensity suddenly. Compared with normal concrete, the maximum increase of the reinforced concrete with steel fiber SQB -32 (Ⅱ) is listed, which compressive, tensile and flexural strength are increased by 30%, 40% and 24%, respectively.
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Nguyen, Duy-Liem, Duc-Kien Thai i Dong-Joo Kim. "Direct tension-dependent flexural behavior of ultra-high-performance fiber-reinforced concretes". Journal of Strain Analysis for Engineering Design 52, nr 2 (luty 2017): 121–34. http://dx.doi.org/10.1177/0309324716689625.
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This research investigated the effects of direct tensile response on the flexural resistance of ultra-high-performance fiber-reinforced concretes by performing sectional analysis. The correlations between direct tensile and flexural response of ultra-high-performance fiber-reinforced concretes were investigated in detail for the development of a design code of ultra-high-performance fiber-reinforced concrete flexural members as follows: (1) the tensile resistance of ultra-high-performance fiber-reinforced concretes right after first-cracking in tension should be higher than one-third of the first-cracking strength to obtain the deflection-hardening if the ultra-high-performance fiber-reinforced concretes show tensile strain-softening response; (2) the equivalent bottom strain of flexural member at the modulus of rupture is always higher than the strain capacity of ultra-high-performance fiber-reinforced concretes in tension; (3) the softening part in the direct tensile response of ultra-high-performance fiber-reinforced concretes significantly affects their flexural resistance; and (4) the moment resistance of ultra-high-performance fiber-reinforced concrete girders is more significantly influenced by the post-cracking tensile strength rather than the tensile strain capacity. Moreover, the size and geometry effects should be carefully considered in predicting the moment capacity of ultra-high-performance fiber-reinforced concrete beams.
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Kang, Su Tae, Jung Jun Park, Gum Sung Ryu, Gyung Taek Koh i Sung Wook Kim. "Comparison of Tensile Strengths with Different Test Methods in Ultra High Strength Steel-Fiber Reinforced Concrete (UHS-SFRC)". Key Engineering Materials 417-418 (październik 2009): 649–52. http://dx.doi.org/10.4028/www.scientific.net/kem.417-418.649.
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Ultra High Strength Steel-Fiber Reinforced Concrete (UHS-SFRC) is characterized by very high compressive and tensile strength that is about 8 times of ordinary concrete, and high ductility owing to the addition of steel fibers. This paper investigates the relationship existing among the direct tensile strength, flexural tensile strength and splitting tensile strength of UHS-SFRC. Differently from ordinary concrete, it is found that the first cracking strengths in UHS-SFRC obtained through direct tensile test and splitting tensile test are similar, while the strength obtained from flexural tensile test is significantly larger than those from other tests. Based on the experimental results, relationships between the direct tensile strength and flexural tensile strength, between the first cracking strengths in direct tensile test and in flexural tensile test, and between the first cracking strength in direct tensile test and the flexural tensile strength are proposed.
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Eid, Rami, Avraham N. Dancygier i Ghali Jaber. "Mechanical Properties of Low-Performance Concrete (LPC) and Shear Capacity of Old Unreinforced LPC Squat Walls". Materials 14, nr 23 (29.11.2021): 7310. http://dx.doi.org/10.3390/ma14237310.
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Low-performance concrete (LPC) is characterized by its low strength and commonly by the presence of large aggregates. This type of concrete was used for construction of load carrying, commonly unreinforced walls in old buildings. The resistance of these buildings with LPC squat walls (of relatively low height-to-length ratio), to in plane horizontal loads, was experimentally investigated in this study. The low compressive strength of these walls, well below that of standard concrete, requires estimation of the relation between the actual LPC compressive strength and its tensile strength, and identification of their failure mode and corresponding shear capacity when subjected to in plane horizontal loads. In this study, compressive and splitting tensile strengths of authentic LPC specimens were measured, and based on them, a relation between the compressive and tensile strengths is proposed. Then, diagonal compression tests were performed on authentic LPC specimens, as well as specimens made of standard concrete. These tests yielded the expected mode of failure of vertical cracking and their analysis shows that their shear capacity needs to be evaluated based on their tensile strength (rather than the flexural shear capacity of unreinforced concrete beams). Thus, the load-bearing (both horizontal and gravitational) capacity to prevent diagonal tension failure of an unreinforced LPC wall can be evaluated by comparing the LPC tensile strength to the major principal stress caused by the load. Assessment of the tensile strength can be based on the relation between the compressive and tensile strengths proposed in this work.
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Oukaili, Nazar. "Unified Methodology for Strength and Stress Analysis of Structural Concrete Members". International Journal of Applied Mechanics and Engineering 26, nr 1 (29.01.2021): 178–200. http://dx.doi.org/10.2478/ijame-2021-0011.
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Abstract In this paper, a methodology is presented for determining the stress and strain in structural concrete sections, also, for estimating the ultimate combination of axial forces and bending moments that produce failure. The structural concrete member may have a cross-section with an arbitrary configuration, the concrete region may consist of a set of subregions having different characteristics (i.e., different grades of concretes, or initially identical, but working with different stress-strain diagrams due to the effect of indirect reinforcement or the effect of confinement, etc.). This methodology is considering the tensile strain softening and tension stiffening of concrete in addition to the tension stiffening of steel bars due to the tensile resistance of the surrounding concrete layer. A comparison of experimental and numerical data indicates that the results, obtained based on this methodology, are highly reliable and highly informative.
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Sadovskaya, E. A., S. N. Leonovich, S. A. Zhdanok i E. N. Polonina. "Tensile Strength of Nanofibrous Concrete". Journal of Engineering Physics and Thermophysics 93, nr 4 (lipiec 2020): 1015–19. http://dx.doi.org/10.1007/s10891-020-02202-8.
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Mohamed, Osama Ahmed, i Omar Fawwaz Najm. "Experimental Validation of Splitting Tensile Strength of Self Consolidating Concrete". Applied Mechanics and Materials 864 (kwiecień 2017): 308–12. http://dx.doi.org/10.4028/www.scientific.net/amm.864.308.
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The American Concrete Institute (ACI) code of concrete design ACI 318, and many other concrete codes report expressions for estimating splitting tensile strength as a function of the specified concrete compressive strength. However, for self-consolidating concreate, research is still needed to develop reliable expressions for the prediction of splitting tensile strength. Mohamed et al. [1] proposed an expression for splitting tensile strength of sustainable self-consolidating concrete in which cement was partially replaced with fly Ash, silica fume, and ground granulated blast furnace slag (GGBS). This paper presents validation of the splitting tensile strength expression using additional test data in which concrete mixes were prepared using various water/cement ratios. expression developed by Mohamed et. al. [1] exhibits excellent correlation with test data as demonstrated in this paper.
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Li, Xiao Fen, i Ping Ren. "Experimental Research on Tensile Strength of Premixed Concrete at Early Ages". Applied Mechanics and Materials 556-562 (maj 2014): 687–91. http://dx.doi.org/10.4028/www.scientific.net/amm.556-562.687.
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The splitting tensile method for the tensile strength of concrete is usually used in structural applications, so it is great important in the investigating the relation between the direct tensile strength and the splitting strength. But the relationship between the splitting strength and the direct tensile strength is not consolidatly confirmed at home and abroad. In order to obtain the exact results, the experimental apparatus for concrete of the direct tension are designed, which resolves the difficulty of ensuring that the load is truly axial. Tests of the direct tension are performanced on three different concrete mixes (C20,C40,C60) at 3, 7, 14 , 28 and 60 days and the test data do not scatter. The relations between the tensile strength and the cube compressive strength are obtained and a formula for investigating the relation between the direct tensile strength and the splitting strength are proposed.
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Tipka, Martin, Jitka Vašková i Jan Vodička. "Tensile Strength Tests for Concrete and Fibre Reinforced Concrete". Solid State Phenomena 272 (luty 2018): 94–101. http://dx.doi.org/10.4028/www.scientific.net/ssp.272.94.
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The paper describes the differences in several test methods, which are used for tensile strength analysis of cementitious composites. It explains tests arrangement, their benefits and disadvantages. The conversion factors between detected strengths were quantified in experiments, depending on the particular composition of the composite.
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Gunasekaran, M., i T. Palanisamy. "Effect of fly ash and bagasse ash on the mechanical properties of light weight concrete". Cement Wapno Beton 27, nr 2 (2022): 72–101. http://dx.doi.org/10.32047/cwb.2022.27.2.1.
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Light weight concrete is an important part in the concrete technology. The use of mineral additives in light-weight concrete, to replace fine aggregate with fly ash and bagasse ash, helps to reduce the cement content. The present investigation aims to meet the performance of light weight concrete, by adding fly ash and bagasse ash, as fine aggregate replacement additives. The strength properties such as cube compressive strength, cylinder compressive strength and split tensile strength were investigated after different ages, to find the optimum addition of mineral additives such as fly ash and bagasse ash, in concrete. The strengths were compared and the optimal replacement level of cement with fly ash and bagasse ash was found. The cylinder compressive strength and split tensile strength of light weight concrete were measured, at the same replacement levels of mineral additives, at the age of 28 days curing. The mathematical equations were proposed to achieve cube compressive and tensile strengths, cylinder compressive and tensile strength and cube compressive and cylinder compressive strengths, concerning typical strength.
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Hemmati Pourghashti, Hamed, Malek Mohammad Ranjbar i Rahmat Madandoust. "Experimental investigation of recycled aggregate effect on the concrete properties". International Journal of Structural Integrity 9, nr 4 (13.08.2018): 560–71. http://dx.doi.org/10.1108/ijsi-10-2017-0057.
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Purpose The purpose of this paper is to conduct a laboratory investigation on measuring the tensile strength of recycled concrete using a double punch test. Furthermore, one of the main goals of this study is to compare the tensile and compressive strengths of recycled concrete samples. Design/methodology/approach Recycled concrete samples were made with variables such as aggregate type (natural stone and aggregate recycled concrete), different water-to-cement ratios and different treatment conditions in the first stage. In the next stage, the double punch test was performed on them, and finally the results obtained from experiments were analyzed and investigated. Findings According to the above tests, it was concluded that: first, according to the laboratory results, the strength of concrete containing recycled aggregates becomes closer to the strength of concrete containing natural aggregates whenever the water-to-cement ratio is higher. Second, upon investigating the treatment conditions, it was observed that the treatment had a greater effect on the strength of the recycled concrete. However, this effect was less tangible in tensile strength. Third, upon investigating the results of tensile strength, it can be said that the Barcelona test results were closer to the direct tensile test results compared to the Brazilian test results. This indicates the higher viability of Barcelona’s test results. Fourth, the results obtained from the Barcelona tensile test for recycled concrete were closer to the results of the direct tensile test compared to the concrete containing natural aggregates, which suggests that the Barcelona test is more suitable as a tensile test for recycled concrete. Fifth, the effects of various factors on tensile strength were somewhat less compared to the compressive strength, although very close. Sixth, the relationships provided by the regulation for concrete tensile strength on compressive strength were highly inconsistent with the results obtained from the direct tensile test, for which the consistency was higher for concrete containing natural aggregates compared to recycled concrete. Seventh, the dispersion of results obtained from tensile tests was higher for recycled concrete compared to concrete containing natural aggregates, but lesser of this dispersion was observed in the compressive strength. Originality/value According to the laboratory results, the strength of concrete containing recycled aggregates becomes closer to the strength of concrete containing natural aggregates whenever the water-to-cement ratio is higher. Upon investigating the treatment conditions, it was observed that the treatment had a greater effect on the strength of the recycled concrete. However, this effect was less tangible in tensile strength. On the basis on the results of the tensile strength, it can be said that the Barcelona test results were closer to the results of the direct tensile test compared to those of the Brazilian test. This indicates the higher viability of Barcelona’s test results. The results obtained from the Barcelona tensile test for recycled concrete were closer to the results of direct tensile test compared to the concrete containing natural aggregates, which suggests that the Barcelona test is more suitable as a tensile test for recycled concrete. The effects of various factors on tensile strength were somewhat less compared to the compressive strength, although very close. The relationships provided by the regulation for concrete tensile strength on compressive strength were highly inconsistent with the results obtained from the direct tensile test, for which the consistency was higher for concrete containing natural aggregate compared to recycled concrete. The dispersion of results obtained from tensile tests was higher for recycled concrete compared to concrete containing natural aggregate, but lesser of this dispersion was observed in the compressive strength.
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Pichugin, Dmitrii Alekseevich, Anastasiya Surikova i Vladimir Alekseevich Surikov. "Analysis of hydraulic concrete strength test methods". Vestnik of Astrakhan State Technical University. Series: Marine engineering and technologies 2022, nr 2 (31.05.2022): 33–43. http://dx.doi.org/10.24143/2073-1574-2022-2-33-43.
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Today, methods of determining the tensile strength of concrete are of considerable interest. These methods using the anisotropy of brittle materials and, in particular, concrete, with respect to compressive and tensile stresses, make it possible, based on the findings of the theory of elasticity, to determine the tensile strength when tested with a compressive load, which can be transferred to the sample much more easily than tensile forces. The results of tests of concrete by the method of compression of cylindrical samples and crushing of cube samples with hewn ribs between two round metal rods lying in the same plane closely match the tensile strength values obtained with direct tension. For all studied compositions, the value of the strength ratio increases as the water-cement ratio increases, both for concrete without additives and with additives of surfactants. Using additives of surface-active organic substances without changing the dependence of the strength ratio on the hardening time makes it smoother. It has been found that the fast decreasing value of the strength ratio, hardening period that corresponds to its minimum value, and further increase or stabilization of Rp / Rc depend on a number of factors of the cement used, storage conditions of surfactant additives, composition, etc. Under the influence of the different factors the position of the characteristic points on the curve of the strength ratio dependence on the hardening time can change and obey the general pattern. For concretes and mortars, the decrease in the strength ratios in the transition from 28 days to the age of 90 days makes up to 10–25% (and in some cases much more), which must be taken into account in appropriate cases when designing structures.
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Zhang, Ju, Chang Wang Yan i Jin Qing Jia. "Compressive Strength and Splitting Tensile Strength of Steel Fiber Reinforced Ultra High Strength Concrete (SFRC)". Applied Mechanics and Materials 34-35 (październik 2010): 1441–44. http://dx.doi.org/10.4028/www.scientific.net/amm.34-35.1441.
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This paper investigates the compressive strength and splitting tensile strength of ultra high strength concrete containing steel fiber. The steel fibers were added at the volume fractions of 0%, 0.5%, 0.75%, 1.0% and 1.5%. The compressive strength of the steel fiber reinforced ultra high strength concrete (SFRC) reached a maximum at 0.75% volume fraction, being a 15.5% improvement over the UHSC. The splitting tensile strength of the SFRC improved with increasing the volume fraction, achieving 91.9% improvements at 1.5% volume fraction. Strength models were established to predict the compressive and splitting tensile strengths of the SFRC. The models give predictions matching the measurements. Conclusions can be drawn that the marked brittleness with low tensile strength and strain capacities of ultra high strength concrete (UHSC) can be overcome by the addition of steel fibers.
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Liu, Guan Guo, Guo Rong Zhang, Yun Sheng Zhang i Lu Lu. "Study on Tensile Creep Characteristics of High Strength Concrete". Applied Mechanics and Materials 835 (maj 2016): 535–41. http://dx.doi.org/10.4028/www.scientific.net/amm.835.535.
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A set of concrete tensile creep testing apparatus was constructed. The tensile creep characteristics of concrete under different loading ages (1d, 3d and 7d), different water-binder ratio (0.29, 0.33 and 0.37) and different fly ash proportion (0%, 20% and 40%) were researched. The results show that tensile creep increases with increasing of water-binder ratio obviously as well as with decreasing of loading ages. The tensile creep is inhibited by addition of fly ash, and the inhibition effect increases with the increase of fly ash proportion. Free shrinkage is counteracted 42%~62% by tensile creep. The internal tension of concrete is effectively relieved so that the possibility of cracking of concrete is decreased at early ages.
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Liu, Xi Liang, Shao Feng Liu, Ben Dong Qin i Da Fang Yang. "Experimental Study on Mechanical Properties of Hybrid Fiber High-Strength Concrete". Applied Mechanics and Materials 204-208 (październik 2012): 3809–14. http://dx.doi.org/10.4028/www.scientific.net/amm.204-208.3809.
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Design 6 different dosages of C70 hybrid fiber high-strength concrete and a group of ordinary-strength concrete C70. By test of compressive strength and splitting tensile strength, discovery the high-strength hybrid fiber concrete compressive strength is not increasing trend; tensile strength increases significantly, average up to 5.12MPa, tension and compression ratio increased by 12%~40%; specimens eventually destroying the near ductility failure, in the case of 1.2% volume dosage of steel fiber and 0.10% volume dosage of polypropylene fiber, tension and compression ratio reach to 0.0683, hybrid fiber high-strength concrete showed good mixing effect, in the large-scale concrete construction has a certain spread value.
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Canseco-Tuñacao, H. A. R., K. Remoto, K. Melendres i I. M. Deguzman. "Recycled Coarse Aggregate from Concrete Waste Using DMDA for Concrete". IOP Conference Series: Earth and Environmental Science 999, nr 1 (1.03.2022): 012003. http://dx.doi.org/10.1088/1755-1315/999/1/012003.
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Abstract This study investigates the effect of the replacement of recycled concrete as coarse aggregates using the Densified Mixture Design Algorithm Method (DMDA) in unconfined concrete behavior. DMDA was applied to produce concrete with the least void. Compressive strength, flexural strength and split tensile strength tests were conducted on 7-, 14-, 28- and 56-day old specimens. Compressive strength test results showed that specimens with 20, 30, and 40% RCA replacements at 56 days are relatively lower compared to the control and with 10% RCA replacement specimens. The compressive strengths of the specimens with RCA replacements decreased as the amount of RCA increased. However, the 10% replacement specimens showed promising performance with an average strength of 3275 psi at 56 days with an 11.2% difference in compressive strength with the control with 0% replacement. A significant increase in compressive strengths between the 28- and 56-day specimens for all specimens was observed and accounted due to the pozzolanic activity of the type C fly ash used as filler. For flexural and splitting tensile strength, results showed that specimens with 40% replacement showed best performance with a 9.87% difference and roughly 1% greater with the control in terms of its flexural and splitting tensile strength, respectively.
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Yao, Weilai, Shiyong Jiang, Wei Fei i Tao Cai. "Correlation between the Compressive, Tensile Strength of Old Concrete under Marine Environment and Prediction of Long-Term Strength". Advances in Materials Science and Engineering 2017 (2017): 1–12. http://dx.doi.org/10.1155/2017/8251842.
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Compressive strength and tensile strength are important mechanical properties of concrete. The long-term strength of concrete under real service environment is an important parameter when evaluating existing buildings, which should also be properly considered in structural design. In this study, the relationship between compressive and splitting tensile strength of old concrete existing for long period under marine environment was investigated. At a deserted harbour, concrete cores samples were drilled by pairs in site. For each pair of samples, the two cores were drilled from the adjacent location and conducted to compressive, splitting tensile test, respectively. 48 compressive and splitting tensile strengths were finally obtained. From the test results, tensile strength presents general uptrend with compressive strength, and the two parameters are well positively correlated. Exponential model generally recommended by building codes or literatures is still capable of describing the relationship between compressive and tensile strength of old deteriorated concrete, when function parameters are properly determined. Based on statistical theory and the experimental result of this study, a method for predicting long-term tensile strength of concrete is developed and an example is given, which may provide a potential way to estimate long-term concrete strength under real marine environment.
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Nesvetaev, G. V., A. V. Dolgova, L. V. Postoj, M. N. Grigoryan i B. M. Yazyev. "Effect of Dosage of Redispersible Powders on the Properties of Fine Concrete". Materials Science Forum 974 (grudzień 2019): 413–18. http://dx.doi.org/10.4028/www.scientific.net/msf.974.413.
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The RPP introduction has been established up to 3% by weight of the dry concrete mix is accompanied by a decrease in the fine-grained concrete tensile strength in compression to 40% and in tension during bending to 15%. The relationship between the tensile strength limit in bending and compression for the studied materials is invariant to the cement and RPP type. With the concrete tensile strength in tensile bending increase, there is a weak tendency to a decrease in the adhesion ratio value to the concrete base and tensile strength. The adhesion amount to the concrete base with RPP increasing dosage can either increase or decrease after a certain limit, depending on the cement properties. The maximum increase in adhesion to the concrete base was 37%, while the decrease in the concrete elasticity initial modulus was 26%.
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Zhang, Lijuan, Jun Zhao, Cunyuan Fan i Zhi Wang. "Effect of Surface Shape and Content of Steel Fiber on Mechanical Properties of Concrete". Advances in Civil Engineering 2020 (21.07.2020): 1–11. http://dx.doi.org/10.1155/2020/8834507.
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Steel fiber reinforced concrete (SFRC) has gained popularity in the last decades attributed to the improvement of brittleness and low tensile strength of concrete. This study investigates the effect of three shapes of steel fibers (straight, hooked end, and corrugated) with four contents (0.5%, 1%, 1.5%, and 2%) on the mechanical properties (compression, splitting tension, shear, and flexure) of concrete. Thirteen groups of concrete were prepared and investigated experimentally. Test results indicated that steel fiber had significant reinforcement on mechanical properties of concrete. When the steel fiber content increases from 0.5% to 2.0%, the compressive strengths increase about 4–24%, splitting tensile strengths increase about 33–122%, shear strengths increase about 31–79%, and flexural strengths increase about 25–111%. Corrugated steel fiber has the best reinforced effect on strength of SFRC, hooked end steel fiber takes the second place, and straight steel fiber is the least. Calculated formulas of compressive, splitting tensile, shear, and flexural strengths were established with consideration of the bonding properties between concrete and steel fiber. Influence factors of steel fiber αf and concrete matrix strength αc were put forward and determined by regression analysis of experimental data. Calculated results agree well with the experimental results.
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Yan, Chang Wang, Jin Qing Jia, Ju Zhang i Rui Jiang. "Compressive Strength and Splitting Tensile Strength of Polyvinyl Alcohol Fiber Reinforced Ultra High Strength Concrete (PFRC)". Advanced Materials Research 150-151 (październik 2010): 996–99. http://dx.doi.org/10.4028/www.scientific.net/amr.150-151.996.
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The marked brittleness with low tensile strength and strain capacities of ultra high strength concrete (UHSC) with compressive strength of 100 MPa can be overcome by the addition of polyvinyl alcohol (PVA) fibers. The compressive strength and splitting tensile strength of ultra high strength concrete containing PVA fibers are investigated this paper. The PVA fibers were added at the volume fractions of 0%, 0.17%, 0.25%, 0.34% and 0.5%. The compressive strength of the PVA fiber reinforced ultra high strength concrete (PFRC) reached a maximum at 0.5% volume fraction, being an 8.2% improvement over the UHSC. The splitting tensile strength of the PFRC improved with increasing the volume fraction, achieving 46.7% improvements at 0.5% volume fraction. The splitting strength models were established to predict the compressive and splitting tensile strengths of the PFRC. The models give predictions matching the measurements.
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Lim, Myunghwan, i Changhee Lee. "Flexural Performance of Reinforced Concrete Members with Steel Bars". Applied Sciences 11, nr 10 (15.05.2021): 4512. http://dx.doi.org/10.3390/app11104512.
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The use of high-tension bars to strengthen flexural members is gaining increasing interest. However, the applicability of current standards to such bars is uncertain, because there may not be a definite yield strength and it may be unclear whether the tensile or compressive failure mode dominates. Determining the balanced–destruction steel ratio is particularly difficult. We measure the bending behaviour of flexural members containing high-tension bars with different yield strengths and tensile steel ratios. We conclude that the maximum-steel-ratio regulation and nominal -strength equation in the current standard remain applicable.
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Mishutin, Andriy, Kos Zeljko, Grynyova Iryna i Lucia Chintea. "Durability of Modified Fiber Concrete for Rigid Pavements". Croatian Regional Development Journal 2, nr 1 (1.06.2021): 30–40. http://dx.doi.org/10.2478/crdj-2021-0006.
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Abstract Modified concretes and fiber concretes for rigid pavements have been investigated. Four-factor experiment was conducted. The amount of Portland cement, polypropylene fiber, metakaolin and polycarboxylate superplasticizer varied in the experiment. All mixtures had the same mobility S2. The active mineral additive metakaolin increases the compressive strength of concrete and its tensile strength in bending. The amount of metakaolin at the level of 15.20 kg/m3 is rational. Due to a decrease in W/C with an increase in the amount of superplasticizer Coral ExpertSuid-5 to 0.9.1%, the compressive strength of concrete increases by 5.7 MPa, the tensile strength in bending increases by 0.5.0.6 MPa. Due to the introduction of polypropylene fiber, the tensile strength of concrete in bending increases by 0.6.0.9 MPa, the frost resistance of concrete increases by 50 cycles. Due to the use of a rational amount of superplasticizer and metakaolin, the frost resistance of concretes and fiber concretes concrete increases by 50-100 cycles. The use of a rational amount of modifiers and fiber reduces the abrasion of concretes by 40.45%. The developed modified fiber concretes of rigid pavements, depending on the amount of Portland cement, have compressive strength from 55 MPa to 70 MPa, tensile strength in bending from 8 MPa to 9.5 MPa, frost resistance from F350 to F450, abrasion from 0.30 to 0.40 g/cm2. Such strength, frost resistance and abrasion resistance allow the use of fiber concretes in pavements with the greatest load and ensures high durability of the material and corresponds to the directions and tasks of the state scientific and technical program “National Transport Strategy of Ukraine for the period up to 2030”
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Shakir Muwashee, Rawa, Hamid Athab Al-Jameel i Qusay Abdulhameed Jabai. "Investigating the Behavior of Concrete and Mortar Reinforced with Aluminum Waste Strips". International Journal of Engineering & Technology 7, nr 4.37 (13.12.2018): 211. http://dx.doi.org/10.14419/ijet.v7i4.37.24103.
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Composite concrete such as fiber reinforced concrete is widely used in structures because of its excellent properties such as compressive, flexural and tensile strengths and also high modulus of elasticity because it gives lower strain values under loading and too fewer cracks propagation. In this study, Aluminum strips was prepared by cutting the Coca- Cola cans as strips in concrete. The reason of using Aluminum strip is low density and good tensile strength (about 310 MPa) and also has a good ductility. The results of this study show good improvements in compressive, tensile and flexural strengths using 117 tested specimens for both concrete and mortar. In brief, about 22 % increment in compressive strength of Aluminum strip concrete and flexural strength increases from 3.31 MPa to 11.20 MPa when using Aluminum strips with 2.5 % by volume of concrete. The reinforced mortar with Aluminum strips demonstrates significant increments which are 27% for compressive strength and more than 100% for both flexural and tensile strengths comparing with reference mix.
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Tu, Nhung Hong, i Cong Thanh Nguyen. "ASSESSMENT OF TENSILE STRENGTH OF CONCRETE IN ACCORDANCE WITH ITS COMPRESSIVE STRENGTH". Scientific Journal of Tra Vinh University 1, nr 41 (29.12.2020): 86–96. http://dx.doi.org/10.35382/18594816.1.41.2020.647.
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Concrete is the primary material used in construction. The importance of concrete is shown through its strength criteria which are indispensable in all structural designs of the engineers. This article is to determine the tensile strength of concrete according to the compressive strength through an experimental study for thestrength grade B15, B20, B25 of concrete. In this study, tensile and compressive strength of concrete were determined by tensile test and compression test on the same sample. The experimental results show that the tensile strength of concrete is much smaller than its compressive strength. For concrete at 28 days, the tensilestrength is 12,0% to 12,8% of the compressive strength. The reliability of the above compressive strength value is ensured by the standard compression test. The results of this study are recommended for practical testing of concrete strength.
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Feng, Jin Cai, Ping Hua Zhu i Qun Xia. "Mechanical Behaviors of Structural Concrete Using Recycled Aggregates from Repeatedly Recycling Waste Concrete". Advanced Materials Research 450-451 (styczeń 2012): 1379–82. http://dx.doi.org/10.4028/www.scientific.net/amr.450-451.1379.
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This paper reports an expermiental study on mechanical behaviors of structural concrete using recycled aggregates from repeatedly recycling waste concrete. Five series of natural aggregate concretes with compressive strengths of 25MPa, 30MPa, 40MPa, 50MPa and 60MPa were used as recycled coarse and fine aggregates to produce recycled concrete with an objective compressive strength of 30MPa after they were cured for 28d. These recycled concretes were used as aggregates to produce concrete with the same objective compressive strength of 30MPa. The cycles were carried on until the indices evaluating the quality of recycled coarse or fine aggregate exceeded the tolerance. The mechanical behaviors of these concrete were tested. The results indicates that that with the increase of the cyclic number, the mechanical properties of recycled concrete, including compressive strength, tensile splitting strength, modulus of elasticity, gradually stabilize after obviously decreaing in the first instance.
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Choi, Yeol, Joo-Won Kang, Tae-Yeon Hwang i Chang-Geun Cho. "Evaluation of residual strength with ultrasonic pulse velocity relationship for concrete exposed to high temperatures". Advances in Mechanical Engineering 13, nr 9 (wrzesień 2021): 168781402110349. http://dx.doi.org/10.1177/16878140211034992.
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This paper presents the results of an experimental investigation on the relationship between strength and ultrasonic pulse velocity (UPV) of concrete exposed to high temperature, especially for a decision of building remodeling of concrete structures. The experiments were conducted at three different initial compressive strength levels for temperature up to 800°C. UPV, Compressive, and splitting tensile tests and UPV measurements were performed for unheated and heated concrete specimens. The measured UPV values in the present work were correlated with compressive and tensile strengths to estimate the strength of concrete. Based on the results, two linear equations for predicting compressive and tensile strength of concrete at elevated temperatures using UPV have been proposed. It is found that the difference of initial compressive strength of concrete does not have a significant effect on the strength reduction ratio after exposed to high temperatures. In addition, the reduction factors of compressive and tensile strengths in the present work do not well comply with the values of suggested by EN 1992-1-2.
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Del Savio, Alexandre Almeida, Darwin La Torre i Juan P. Cedrón. "Experimental Volume Incidence Study and the Relationship of Polypropylene Macrofiber Slenderness to the Mechanical Strengths of Fiber-Reinforced Concretes". Applied Sciences 12, nr 18 (11.09.2022): 9126. http://dx.doi.org/10.3390/app12189126.
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An experimental study was conducted to examine the mechanical strengths of concretes with straight high-strength knurled polypropylene macrofibers. Incidences of concrete mechanical strengths were determined for three different fiber dosages and lengths. In addition, compressive, indirect-splitting-test tensile, and flexural strengths were determined through testing. The results showed no statistically significant correlation between the volume and length of fibers with the compressive strength of polypropylene fiber-reinforced concrete (PPFRC). However, there was a statistically significant correlation between the split tensile strength, the volume, and the length of the fibers when the volume was greater than 0.80%, and the length of the fibers was greater than 50 mm. Furthermore, the modulus of rupture increased when the volume of fibers was greater than 0.80% and the length of the fibers was 60 mm. Finally, equations were proposed to determine the tensile strength by split test and the modulus of rupture as a function of the mixture’s resistance without fibers, the fibers’ volume and length.
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Yuan, Jian Song, Dan Ying Gao i Lin Yang. "Research on Strength of Steel Fiber Reinforced Concrete at Low Fiber Volume Fraction Based on Binary Variance Analysis". Advanced Materials Research 742 (sierpień 2013): 243–48. http://dx.doi.org/10.4028/www.scientific.net/amr.742.243.
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Based on the strength tests, including compressive strength, split tensile strength, shear strength , of steel fiber reinforced concrete (SFRC) with different concrete strength grades (C20~C50) at low fiber volume fraction (0~0.7%), the influences of concrete strength grades and steel fiber volume on concrete strengths were studied, and the effect significance levels of the two factors was analyzed through the binary variance analysis. The results show that when the concrete strength grades are amongst C20 ~ C50 and steel fiber volume rates lie in the range 0~0.7%,the strengths of SFRC rises as concrete strength grade and steel fiber volume ratio increase ; the influence of concrete grade is more significant than that of steel fiber volume ratio on compressive strength and split tensile strength of SFRC; the influence of steel fiber volume fraction is less significant than that of concrete strength grades on shear strength of SFRC.
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Asgarinia, Khashayar. "The Effect of Nanosilica and Steel Fibers on The Mechanical Behavior of Structural Lightweight Concrete". Journal of Cement Based Composites 4, nr 1 (17.02.2023): 1–4. http://dx.doi.org/10.36937/cebel.2023.5790.
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The low strength of lightweight aggregates diminishes the strength of lightweight concrete, and the concrete's fragility impedes the ductile behavior of structures subjected to seismic stresses. The use of reinforcing materials and fibers may increase the strength of lightweight concrete by compensating for the impact of reduced strength caused by the use of lightweight particles and preventing the rapid breakdown of concrete. The performance of the materials used is an effective determinant of structural member behavior. Therefore, for computational analysis of finite elements to accurately anticipate the behavior of structural parts, precise behavioral models of materials are required. This study studied the tensile behavior of lightweight structural concrete containing steel fibers (at a volume percentage of 1%) and nanosilica reinforcing pozzolan (at a weight percentage of between 1 and 3%), using tensile strength as one of the influencing factors. together with the strain corresponding to the maximal stress. The inclusion of steel fibers and nanosilica had the largest influence on enhancing the tensile behavior of lightweight concrete, according to the data. By adding 3% nanosilica and 1% steel fibers to light concrete, the direct tensile strength has risen by 74%. In addition, the indirect tensile strength is somewhat greater in all samples than the direct tensile strength.
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G, Mr Venkatesan, Poovadharani R i Neerkamali L. "Experiment Investigation On Concrete With Partial Replacement Of Cement By Cow Dung Ash". Journal of University of Shanghai for Science and Technology 23, nr 10 (12.10.2021): 439–46. http://dx.doi.org/10.51201/jusst/21/09698.
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Experimental investigations were carried out to study the cow dung ash on the strength of concrete. Cement was partially replaced with four percentages (5%, 10%, 15%, 20%) of cow dung ash by weight in M20 grade concrete mix. Test performed on the concrete mix are compressive strength, splitting tensile strength and workability. The compressive strengths of the concrete specimens were determined at 7 and 28 days respectively. The tests were performed on the moulds of size (150mm x150mm x150mm).Workability test is done using compaction factor apparatus. Workability Test shows that workability of concrete decreases as percentage of cow dung ash increases in concrete mix. When compared to normal concrete the concrete containing 10% of CDA has 17% increase in compressive strength and 15% increase in Tensile Strength. The Compressive Strength and Tensile strength tends to decrease after 10%. Thus 10% replacement of cement by CDA gives satisfactory result.
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Denesh, Mr K. C., i V. Senthilkumar. "Experimental Study on The Steel Fiber Reinforcement Concrete". International Journal for Research in Applied Science and Engineering Technology 11, nr 1 (31.01.2023): 710–13. http://dx.doi.org/10.22214/ijraset.2023.48670.
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Abstract: Concrete is one of the world most widely used construction material. However, since the early 1800’s, it has been known that concrete is weak in tension. Weak tensile strength combined with brittle behavior result in sudden tensile failure without warning. This is obviously not desirable for any construction material. Thus, concrete requires some form of tensile reinforcement to compensate its brittle behavior and improve its tensile strength and strain capacity to be used in structural applications. Historically, steel has been used as the material of choice for tensile reinforcement in concrete. Unlike conventional reinforcing bars, which are specifically designed and placed in the tensile zone of the concrete member, fibers are thin, short and distributed randomly throughout the concrete member.
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Guo, Chao, i Zhengran Lu. "A 3D FEM Mesoscale Numerical Analysis of Concrete Tensile Strength Behaviour". Advances in Materials Science and Engineering 2021 (12.07.2021): 1–14. http://dx.doi.org/10.1155/2021/5538477.
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A three-dimensional (3D) finite element method (FEM) based on an inserted cohesive element numerical analysis procedure was developed for concrete mesoscale systems on the ABAQUS platform with python scripts. Aggregates were generated based on dividing the existing geometrical element algorithms to randomize arbitrary spheres. Simultaneously, randomizations of the maximum aggregate size and uniform distributions of aggregate particles were also considered. An FEM for the mortar phase in concrete mesoscale systems was generated along with the interfacial transition zone (ITZ) by inserting a cohesive element. Numerical parameter analyses were performed for nine different concrete systems by varying the coarse aggregate volume fraction (α) and the ITZ tension strength (ITZ-S). The mechanical performance of concrete systems with the coupling effects of α and ITZ-S was evaluated for simulated tensile loading. The results of the numerical simulations for mechanical properties, such as the simulated tensile strengths and tension damage behaviour of concrete systems, were verified with experimental results. The proposed aggregate and ITZ generation approach and numerical simulation procedure can be used by researchers to better understand how aggregate volume fraction and ITZ strength affect the tensile behaviour of concrete mesoscale systems.
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Yu, Ziruo, Zhiguang Li, Yuran Jiang i Yue Wang. "Mechanical Behavior of Reactive Powder Concrete Subjected to Biaxial Loading". Advances in Civil Engineering 2022 (1.07.2022): 1–11. http://dx.doi.org/10.1155/2022/9246692.
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To investigate the biaxial mechanical characteristics of reactive powder concrete (RPC), RPC plate specimens and bone-shaped specimens were tested under compression-compression and compression-tension loadings, respectively. The strengths and strains of the specimens were recorded, and the crack patterns and failure modes in various stress states were examined. Based on the test data, the characteristics of biaxial strength were analyzed, and a biaxial failure criterion was established. The characteristics of major stress-strain curves and failure modes in different biaxial stress states were determined. The results show that the ratio between the biaxial compression strength and the uniaxial compression strength was 1.44–1.58 for RPC. When the stress ratio under compression-tension was −0.05, the tensile strength decreased by 48%. Under compression-compression, the proportional limit of RPC was about 95%, and its peak strain was high. Under compression-tension, as the compressive stress increased, the elastic modulus decreased, and the peak strain in the tensile direction increased. When the RPC specimens were under compression-compression, the failure mode of RPC was splitting failure. Under compression-tension, the failure mode changed from single-crack tensile failure to multicrack compressive failure with increasing confining stress.
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Akita, Hiroshi, Dariusz Alterman i Hideo Koide. "Size Effect of Concrete in Uniaxial Tension". Advanced Materials Research 41-42 (kwiecień 2008): 227–32. http://dx.doi.org/10.4028/www.scientific.net/amr.41-42.227.
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In order to investigate the size effect of concrete, four sizes of rectangular prisms were tested in uniaxial tension. The cross sections of the prisms were 50x100mm, 100x100mm, 200x100mm and 400x100mm. The concrete was an ordinary one with the compressive strength of 34 MPa and the maximum aggregate size of 20mm. Notches were applied on four side faces and secondary flexure was completely eliminated during the test in order to obtain the exact nominal tensile strength. The size effect was analyzed by four factors, namely tensile strength, fracture energy, critical crack opening displacement and tension softening curves. Clear size dependence was observed in critical crack opening displacement and initial convexity of tension softening curves, and a slight size dependence was observed in tensile strength. On the other hand, size effect was unclear in fracture energy and other part of tension softening curves because of their scatters.
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Iqbal, S., N. Ullah i A. Ali. "Effect of Maximum Aggregate Size on the Bond Strength of Reinforcements in Concrete". Engineering, Technology & Applied Science Research 8, nr 3 (19.06.2018): 2892–96. http://dx.doi.org/10.48084/etasr.1989.
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The bond between reinforcements and concrete is the only mechanism that transfers the tensile stresses from concrete to reinforcements. Several factors including chemical adhesion, roughness and reinforcement interface and bar bearing affect the bond strength of reinforcements with concrete. This work was carried out considering another varying factor which is maximum aggregate size. Four mixes of concrete with similar compressive strengths but different maximum aggregate sizes of 25.4mm, 19.05mm, 12.7mm and 9.53mm were used with the same bar size of 16mm. Compressive strength, splitting tensile strength and bond strength for each concrete mix were studied. Test results depict a slight increase in compressive and splitting tensile strength with decrease in maximum aggregate size. The bond strength remained at the same level with decrease in maximum aggregate size except at maximum aggregate size of 9.53mm when there was a drop in bond strength, despite better compressive and splitting tensile strengths. ACI-318 and FIB-2010 codes equation for bond strength calculation work well only when the maximum aggregate size is 12.7mm and above. Therefore, maximum aggregate size is critical for bond strength when smaller size aggregates are used.
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Kadhem, Ali Abbas, Hayder Abbas Al-Yousefi i Qusay A. Jabal. "Effects of Using Corn Cover Fibers on Some Mechanical Properties of Concrete". Key Engineering Materials 895 (3.08.2021): 41–49. http://dx.doi.org/10.4028/www.scientific.net/kem.895.41.
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This investigation aims to use corn cover as natural fibers in concrete mixes to improve some mechanical properties like compressive strength, tensile strength, and flexural strength. using any type of fiber in concrete, in general, can improve the tensile and flexural strength of concrete. Concrete is weak in tension, so using fibers such as natural fibers like trunk fibers or industrial fibers such as steel fibers can improve tensile, the flexural strength of concrete and that may be decreasing the use of steel reinforcement in concrete, and also fibers can improve toughness and ductility of concrete because of its work inside the concrete that can reduce the propagation of cracks under loading. This study shows slight improvement on compressive strength by using fibers, but high increments in flexural strength, the optimum ratio of corn cover fibers was 2.5% by weight of cement which gives the highest values in compressive strength and flexural strength. compressive strength increased from (31.2 to 35.9) MPa (about 15% increment), increment for flexural strength was 70.6% for the optimum fibers content and the failure by using corn fibers was a ductile failure compared with plain concrete that gives sudden failure under flexure load, also tensile strength increased by using fibers, more fibers content beyond or more than 2.5% give lower values for the mechanical properties.
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Adamu, I. M., J. M. Kaura, A. Lawan i A. Ocholi. "Effect of nanosilica on the mechanical and microstructural properties of a normal strength concrete produced in Nigeria". Nigerian Journal of Technology 39, nr 3 (16.09.2020): 710–20. http://dx.doi.org/10.4314/njt.v39i3.9.
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The failure of conventional concrete to have classical mechanical properties, reduced permeability and lead to sustainability in concrete production called for the use of supplementary Cementitious Materials (SCM) in concrete to improve its performance. This study investigates the effect of adding optimal dosage of an SCM called nanosilica (nS) on the tensile and compressive strengths, microstructural properties and cement hydration reaction for grade 30 concrete. The optimal dosage of the nS was determined to be 1.5% by weight of cement using compressive strength test. The influence of optimal nS dosage on the concrete properties was investigated using compressive strength test, splitting tensile strength test, Scanning Electron Microscopy (SEM) and Energy Dispersion Spectroscopy (EDS). Results revealed that optimal nS addition led to 30% and 23.3% respective increase in compressive and tensile strengths of conventional concrete at 7days of curing. SEM micrographs show better packing density in the nano-concrete at 90days of curing. EDS shows that addition of optimal nS dosage in concrete led to formation of more C-S-H gels at 90days curing period, and a corresponding reduction in Ca/Si ratio of the nano-concrete to 0.89; a ratio that is very close to that of 14Ǻ tobermorite reported in literature. The optimal nano-concrete can be used where strength improvement, especially at early age and reduction in concrete permeability are requirements.
Keywords: Compressive strength, Tensile strength, Normal strength nano-concrete, SEM, EDS.