Journal articles on the topic 'Direct tensile strength'
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1
Liu, Jie, Gangyuan Jiang, Taoying Liu, and Qiao Liang. "The Influence of Loading Rate on Direct and Indirect Tensile Strengths: Laboratory and Numerical Methods." Shock and Vibration 2021 (November 29, 2021): 1–17. http://dx.doi.org/10.1155/2021/3797243.
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To investigate different responses of direct and indirect tensile strengths to loading rate, direct and indirect tension tests were performed on sandstone, rust stone, and granite specimens. Typical load curves indicate that a peak tensile stress frequently appears before the second peak stress, used to calculate the tensile strength in indirect tension tests. As expected, increase in the loading rate increases the tensile strength. In addition, the calculated tensile strengths of the indirect tension tests are frequently higher. Interestingly, the increase ratio of the tensile strength with the increase in the loading rate in indirect tension tests is higher. To verify the above results, crack propagation and stress evolution in direct and indirect tension tests were dynamically monitored using PFC 3D. For direct tension tests, specimens fail at the peak tension point, corresponding to the tensile strength. However, for indirect tension tests, minor cracks, composing of continuous microcracks, form before the peak stress and accompany with the decreased slope of the compression curve. At the peak point, tensile stresses significantly concentrate at the crack tips and further cause large-scale crack propagation. In addition, the initiation stress instead of the peak tensile stress is closer to the tensile strength, obtained from the direct tests for the same loading rate.
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Liao, Wen-Cheng, Po-Shao Chen, Chung-Wen Hung, and Suyash Kishor Wagh. "An Innovative Test Method for Tensile Strength of Concrete by Applying the Strut-and-Tie Methodology." Materials 13, no. 12 (June 18, 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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Kang, Su Tae, Jung Jun Park, Gum Sung Ryu, Gyung Taek Koh, and 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 (October 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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Li, Xiao Fen, and Ping Ren. "Experimental Research on Tensile Strength of Premixed Concrete at Early Ages." Applied Mechanics and Materials 556-562 (May 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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Khan, Mohammad Iqbal. "Direct Tensile Strength Measurement of Concrete." Applied Mechanics and Materials 117-119 (October 2011): 9–14. http://dx.doi.org/10.4028/www.scientific.net/amm.117-119.9.
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The evaluation of the tensile strength and determination of the tensile stress-strain curve using indirect tests becomes approximate hence there is a necessity for exploring direct tensile strength measurement. This investigation is part of ongoing research on the development of direct tensile strength measurement. In this paper direct tensile strength test has been proposed and the results obtained have been compared with compressive strength and flexural strength. It has been found that results obtained are well comparable and relationships are similar to that proposed in earlier findings.
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Gao, Min, Zhengzhao Liang, Shanpo Jia, and Jiuqun Zou. "Tensile Properties and Tensile Failure Criteria of Layered Rocks." Applied Sciences 12, no. 12 (June 15, 2022): 6063. http://dx.doi.org/10.3390/app12126063.
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Rocks are less resistant to tension than to compression or shear. Tension cracks commonly initiate compression or shear failure. The mechanical behavior of layered rocks under compression has been studied extensively, whereas the tensile behavior still remains uncertain. In this paper, we study the effect of layer orientation on the strength and failure patterns of layered rocks under direct and indirect tension through experimental and numerical testing (RFPA2D: numerical software of Rock Failure Process Analysis). The results suggest that the dip angle of the bedding planes significantly affects the tensile strength, failure patterns, and progressive deformation of layered rocks. The failure modes of the layered specimens indicate that the tensile strength obtained by the Brazilian disc test is not as accurate as that obtained by the direct tension test. Therefore, the modified Single Plane of Weakness (MSPW) failure criterion is proposed to predict the tensile strength of the layered rocks based on the failure modes of direct tension. The analytical predictions of the MSPW failure criterion agrees closely with the experimental and numerical results. In rock engineering, the MSPW failure criterion can conveniently predict the tensile strength and reflect the failure modes of layered rocks (such as shale, slate, and layered sandstone) with satisfactory accuracy.
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He, Xi Xi, and Ping Fang. "Influence of Concrete Strength Grade and Age on Three Tensile Strengths." Advanced Materials Research 450-451 (January 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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Gong, Fengqiang, Le Zhang, and Shanyong Wang. "Loading Rate Effect of Rock Material with the Direct Tensile and Three Brazilian Disc Tests." Advances in Civil Engineering 2019 (March 10, 2019): 1–8. http://dx.doi.org/10.1155/2019/6260351.
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A series of experimental tests were conducted to investigate the effects of loading rate on the tensile strength of sandstone by using four test methods, including a direct tensile method and three typical Brazilian disc methods (plate loading, circular arc loading, and strip loading). The loading rates used in these tests varied from 10−2 MPa/s to 100 MPa/s. The results show that the rate effects are clear for these test methods, and the tensile strength of sandstone will increase linearly with the logarithm of the loading rate. At the same loading rate, it is found that the tensile strengths of the sandstone specimens under plate loading and arc loading are relatively similar and are much greater than the direct tensile strength, while the tensile strength under strip loading is less than the direct strength. A comprehensive comparison suggested that the strip loading method can be adopted for the Brazilian disc test, while the obtained strength should be modified with a coefficient of 1.37 to obtain the direct tensile strength.
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Zhu, Yu Ting, Dong Tao Xia, and Bo Ru Zhou. "Experimental Study on Axial Tensile Strength of Low Volume Fraction of Ternary Hybrid Fiber Reinforced Concrete." Advanced Materials Research 906 (April 2014): 329–34. http://dx.doi.org/10.4028/www.scientific.net/amr.906.329.
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In this paper, according to the national standard and testing methods,the direct tension strength,splitting tensile strength and cubic compressive strength test were carried out for 8 different groups of hybrid fiber (containing steel fiber, macro-polypropylene fiber and dura fiber) reinforced HPC specimens.The results showed that when the volume proportion of ternary hybrid fiber was less than 1%, there was not obvious influence for the concrete compressive strength, but the splitting tensile strength increased by 26% ~ 69%; the ratio between splitting tensile strength and compressive strength for HFRC increased to 1/12~1/9. When added 0.7% steel fiber, 0.19% macro-polypropylene fiber and 0.11% dura fiber, the confounding effect was the best. Based on the advantages and disadvantages of tensile splitting strength and direct tensile strength test and the results of tests, the concept of equivalent tensile strength and calculative formula was put forward .
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Zhang, Shu, Yubin Lu, Xiquan Jiang, and Wei Jiang. "Inertial effect on concrete-like materials under dynamic direct tension." International Journal of Protective Structures 9, no. 3 (March 29, 2018): 377–96. http://dx.doi.org/10.1177/2041419618766156.
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The inertial effect on the dynamic strength enhancement of concrete-like materials has been widely concerned and its influence on the dynamic tensile strength is particularly controversial, causing great disturbance to dynamic measurement. Therefore, both the experimental and the numerical analyses on the tubular specimens of concrete-like materials are conducted to further investigate the degree of inertial effect under dynamic direct tension. The inertial effect is one of the structural effects, and therefore the tubular specimens with different inner diameters are employed to demonstrate the different influences of inertial effect on the dynamic tensile strength of concrete-like materials. The experimental and numerical results indicate that the inertial effect has some influence on dynamic tensile strength, which increases with strain rate. In addition, the surface area of concrete-like materials will be greatly affected by inertial effect under dynamic tensile loading.
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Závacký, Martin. "A COMPARISON OF TESTING METHODS FOR DETERMINATION OF SPRAYED CONCRETE TENSILE STRENGTH." Acta Polytechnica CTU Proceedings 23 (July 30, 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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Nafisi, Ashkan, Douglas Mocelin, Brina M. Montoya, and Shane Underwood. "Tensile strength of sands treated with microbially induced carbonate precipitation." Canadian Geotechnical Journal 57, no. 10 (October 2020): 1611–16. http://dx.doi.org/10.1139/cgj-2019-0230.
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During large earthquake events where bending moments within soil cements are induced, the tensile strength of cemented soil may govern the deformational behavior of improved ground. Several studies have been conducted to assess the tensile strength of artificially cemented sands that use Portland cement or gypsum; however, the tensile strength of microbially induced carbonate precipitation (MICP)-treated sands with various particle sizes measured through direct tension tests has not been evaluated. MICP is a biomediated improvement technique that binds soil particles through carbonate precipitation. In this study, the tensile strength of nine specimens were measured by conducting direct tension tests. Three types of sand (coarse, medium, and fine) were cemented to reach a heavy level of cementation (e.g., shear wave velocity of ∼900 m/s or higher). The results show that the tensile strength varies between 210 and 710 kPa depending on sand type and mass of carbonate. Unconfined compressive strength (UCS) tests were performed for each sand type to assess the ratio between tensile strength and UCS in MICP-treated sands. Scanning electron microscopy (SEM) images and surface energy measurements were used to determine the predominant failure mode at particle contacts under tensile loading condition.
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Lin, Wei Ting. "Effect of Fiber Length on Direct Tensile and Impact Strength of Cmentitious Materials Containing Silica Fume." Applied Mechanics and Materials 764-765 (May 2015): 37–41. http://dx.doi.org/10.4028/www.scientific.net/amm.764-765.37.
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This study is aimed to evaluate the tensile strength and impact resistance of cementitious materials which comprise steel fibers and silica fume in the mixes. Material variables include water-binder ratio, dosage of silica fume, steel fiber length and dosage. A designed tensile strength was used to perform the direct tensile in this study. Test results indicate that the compressive strength, splitting tensile strength and direct tensile strength of specimens for fiber length of 60 mm are higher than that of 35 mm. The inclusion of fibers in specimens containing silica fume has higher compressive and tensile strength; and lower impact resistance than the specimens made with silica fume. Incorporation of steel fiber and silica fume in composites achieves significantly higher increase in compressive strength, splitting tensile strength, and direct tensile strength than only individual use of steel fiber or silica fume and decrease in impact resistance than only individual use of steel fiber. Finally, the proposed direct tensile testing method is suitable for determining the tensile strength of fiber reinforce cementitious materials and generating the tensile stress-strain curves easily.
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Tomiczek, K. "A study of rock response to failure in the context of the bending properties and comparison with uniaxial tensile and compression behaviour." IOP Conference Series: Earth and Environmental Science 1049, no. 1 (June 1, 2022): 012010. http://dx.doi.org/10.1088/1755-1315/1049/1/012010.
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Abstract The phenomenon of rock bending occurs during underground exploitation, construction of underground excavations and tunnels, and even rising heading – shafts. It is also common in building engineering, e.g., in the case of floors. Rocks and concretes as granular materials on the aggregate scale are fractured as a result of exceeding shear and tensile strength. In a complex state of stress – bending, crack propagation occurs from tensioned to compressed fibres. Three-point bending tests of medium-grained quasi homogeneous and isotropic sandstone were tested for strength and deformation properties of rocks. The E deformability modules for compressed and tensioned fibres as well as strains at failure were determined. The results of three-point bending were compared with the results of uniaxial compression and direct tension. Clear differences were found in the values of strengths, moduli of deformation and strains at failure. The bending strength B of about 9.5MPa is almost 3 times greater than the direct tensile strength σT of about 3.2MPa and is 1/10 of the ultimate uniaxial compression strength σC . With three-point bending, the values of the moduli E are equal to: for tensioned fibres about 6.7GPa, for compressed fibres 14.6GPa; in uniaxial compression tests about 13.0GPa and in direct tensile tests 4.8GPa. Rock material was also failure at various strains values at the ultimate strength. In the case of three-point bending tests, the strains at failure were equal to: for tensioned fibres about 0.125%, and for compressed fibres 0.065%; in uniaxial compression tests εz were equal to about 0.63% and in direct tension tests 0.07%.
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Lee, Hojae, Jang-Ho Jay Kim, Jae-Heum Moon, Won-Woo Kim, and Eun-A. Seo. "Evaluation of the Mechanical Properties of a 3D-Printed Mortar." Materials 12, no. 24 (December 8, 2019): 4104. http://dx.doi.org/10.3390/ma12244104.
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The mechanical properties of 3D-printed mortars are determined in terms of their compressive and direct tensile bond strengths. To determine such properties using existing methods, a preliminary experiment was conducted. The compressive strength of the printed mortar was compared to mold-casted specimens and it was found that the compressive strength decreased by ~30%. Among the fabrication variables, an increase in nozzle height negatively influenced the direct tensile bond strength. For the same conditions and age, the direct tensile strength decreased by as much as 16–29% when the number of layers increased from 2 to 6. When the specimens were fabricated using a specially designed stainless steel frame and core drill, followed by extraction and the application of physical impact, the 28 days compressive strength of the specimen decreased by ~50%.
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Hemmati Pourghashti, Hamed, Malek Mohammad Ranjbar, and Rahmat Madandoust. "Experimental investigation of recycled aggregate effect on the concrete properties." International Journal of Structural Integrity 9, no. 4 (August 13, 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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Rao, Qiuhua, Zelin Liu, Chunde Ma, Wei Yi, and Weibin Xie. "A New Flattened Cylinder Specimen for Direct Tensile Test of Rock." Sensors 21, no. 12 (June 17, 2021): 4157. http://dx.doi.org/10.3390/s21124157.
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In recent decades, researchers have paid more attention to the indirect tensile test than to the direct tensile test (DTT) of rocks, mainly due to difficulties in the alignment and the stress concentration at the end of an intact cylindrical specimen. In this paper, a new flattened cylinder specimen and a clamp device were designed to obtain the true tensile strength of the rock in DTT. Stress distributions of the specimen with different lengths (l) and cutting thicknesses (t) were analyzed, and damage processes of the specimen were monitored by the Digital Image Correlation (DIC), the fractured sections were also scanned. Different mechanical parameters were also obtained by the DTT of the flattened cylinder specimens and the intact cylinder specimens, as well as the Brazilian disc. Research results show that the tensile strength obtained by DTT is smaller than the Brazilian disc and is slightly greater than the intact cylindrical specimen. The flattened cylinder specimen with 0.20 ≤ 2t/D < 0.68 and 0.10 ≤ l/D ≤ 0.20 is recommended to measure the true tensile strength of rock material in DTT. This new shape of the specimen is promising to be extended in the uniaxial or triaxial direct tension test.
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Nguyen, Duy-Liem, Duc-Kien Thai, and Dong-Joo Kim. "Direct tension-dependent flexural behavior of ultra-high-performance fiber-reinforced concretes." Journal of Strain Analysis for Engineering Design 52, no. 2 (February 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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Li, Ping, Yong Chi Li, Shi Wei Duan, and Rui Yuan Huang. "A Contrast Experimental Study of C40 Concrete Tensile Strength." Advanced Materials Research 815 (October 2013): 700–706. http://dx.doi.org/10.4028/www.scientific.net/amr.815.700.
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In order to obtain the tensile strength of the C40 concrete accurately, the comparative study between Brazilian disc splitting experiment and the direct tensile experiment is conducted with a self-modified tensile loading device. The study shows that the tensile strength observed from the direct tensile experiments (3.64MPa) is lower than that from the experiments (5.44MPa). A comprehensive analysis of experimental results is conducted focusing on the perspectives of the specimen failure forms, energy dissipation, the correlation of strength and hydrostatic pressure etc. The study suggests that the main reasons for the differences between Brazilian tensile experimental strength and direct tensile experimental strength include the surface energy required by the specimen destruction, the bond strength between the aggregate, the hydrostatic pressure in the process of loading and other factors.
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Han, Ta Yuan, Wei Ting Lin, An Cheng, and Chin Cheng Huang. "A Direct Method to Evaluate the Tensile Strength of Polyolefin Fiber Cement-Based Composites." Advanced Materials Research 586 (November 2012): 99–102. http://dx.doi.org/10.4028/www.scientific.net/amr.586.99.
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This study is aimed to evaluate the tensile strength of cement-based composites which comprise polyolefin fibers and silica fume in the mixes. Material variables include water-cementitious ratio, dosage of silica fume, steel fiber length and dosage. Test results indicate that the compressive strength and direct tensile strength of specimens for fiber length of 25 mm are higher than that of 50 mm. The strength properties increase with increasing fiber content. Incorporation of fiber and silica fume in composites achieves significantly higher increase in compressive strength and direct tensile strength than only use of fiber or silica fume. In addition, the compressive strength, splitting tensile strength, direct tensile strength and impact resistance are fairly correlated. It contributes that the fiber content influences crack arresting ability and the silica fume influences interfacial bonding effectively.
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Chakrabarti, Srijib, and Jayantha Kodikara. "Direct tensile failure of cementitiously stabilized crushed rock materials." Canadian Geotechnical Journal 44, no. 2 (February 1, 2007): 231–40. http://dx.doi.org/10.1139/t06-102.
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Tensile behaviour plays a very significant role in the performance of cement-stabilized pavements under traffic, as well as under environmental loading. This paper reports the results of direct tensile strength tests undertaken using new equipment. The tests were performed on specimens of crushed basaltic rock stabilized with three binders, namely, general purpose Portland (GP) cement, general blended (GB) cement, and alkali activated slag (AAS), with application rates of 2%, 3%, and 4% by dry weight. Some tests were conducted by adding 6% and 15% highly plastic clay to crushed basaltic rock. The tests showed that while the tensile strength increased with curing time, the failure tensile strain decreased. The ratio of unconfined compressive strength to tensile strength decreased with curing time, but it stabilized within the range 8–12 after about 7 days of curing. For AAS and GB cement, the failure tensile strain decreased with curing time, stabilizing at about 50 microstrains after 7 days of curing, whereas for GP cement, the failure tensile strain did not change significantly during curing, displaying a value around 40 microstrains. The test results also indicated that the presence of reactive fine-grained soil may have had a significant adverse effect on the potential for cracking in the stabilized pavement materials.Key words: pavement materials, cement stabilization, tensile strength, cracking potential.
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Bouafia, Youcef, M. Said Kachi, Djamel Atlaoui, and Said Djebali. "Study of Mechanical Behavior of Concrete in Direct Tensile Fiber Chips." Applied Mechanics and Materials 146 (December 2011): 64–73. http://dx.doi.org/10.4028/www.scientific.net/amm.146.64.
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In this experimental study, we are interested in local fiber wavy chips derived from waste machining steel parts. This work has focused on studying the mechanical behavior of reinforced concrete, with this type of fiber, in direct tensile. Direct tensile tests were carried out on samples in free weights section and square (100x100) mm2. This test involves the design and the implementation of special mounting specimens on the tensile machine type Ibertest. Five (05) fibers percentages were retained in (W = 0.5%. W = 0.8%, W = 1%, W = 1.2%, W = 1.5% with W: volume fraction of added fiber) and two (02) concrete witness whose report on gravel sand is equal to: S / G = 0.8 and S / G = 1. The fibers have been characterized to the strength and tear by the tensile test. The interest lies in optimizing the fiber length and the number of undulations to use in a cement matrix, which will improve the mechanical properties especially tensile strength and post-cracking behavior. The comparison of different results obtained in direct tension on different percentages of fiber, as well as two reports showed that the fibers have conferred a significant ductility to the material after cracking of concrete for different percentages of fiber and a strength for improving the S / G = 0.8.
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Izumi, Hiroki, Juniti Arai, and Toshiaki Mizobuchi. "Study on Characteristics of Tensile Strength of Concrete Considering Temperature Dependence in Mass Concrete Structures." MATEC Web of Conferences 199 (2018): 11012. http://dx.doi.org/10.1051/matecconf/201819911012.
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It is important to grasp mechanical and thermal properties in order to verify the possibility of thermal cracking. In this study, for the purpose of improving the accuracy of analysis in prediction of cracking caused by thermal stress, it was investigated that the direct tensile strength and thermal properties considering temperature history inside concrete member may be applied as a design values for the analysis of prediction of cracking caused by thermal stress. From results of these experiments, in early age, the direct tensile strength under mass curing which is considered temperature history inside concrete member is higher than the splitting tensile strength under standard curing. Which is cured under water of 20°C. However, the direct tensile strength under mass curing is lower than the splitting tensile strength under standard curing after 7 days. At 28 days, the strength of former was about 20% lower than that of latter. In this study, the estimated formula on the strength development of the direct tensile strength was proposed. And the thermal expansion coefficient was estimated using measured values of strain and temperature. In this paper, it was reported that the test method of direct tensile strength considering temperature history inside concrete member was proposed and that the accuracy of analysis for the prediction of thermal cracking by using this method would be improved.
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Zhang, Qian, Zhihe Fang, Yiheng Xu, and Zhao Ma. "Calculation Derivation and Test Verification of Indirect Tensile Strength of Asphalt Pavement Interlayers at Low Temperatures." Materials 14, no. 20 (October 13, 2021): 6041. http://dx.doi.org/10.3390/ma14206041.
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When the direct tensile test is adopted to determine the interlayer tensile strength of the asphalt pavements, specimen separation or internal cracking often occurs at the bonding area of the loading head, rather than at the interlaminar bonding interface. In view of the tedious and discrete data of the direct tensile test, this paper attempts to introduce an indirect tensile test to determine the interlayer bond strength of asphalt pavement to solve this problem. However, the indirect tensile test method of a binder lacks the corresponding mechanical theory. This paper deduces the calculation formula of the indirect tensile strength of a binder based on elastic theory. A mechanical model of the test was established with the finite element method. In accordance with the two-dimensional elastic theory and the Flamant solution, an analytical solution of tensile stress in the indirect tensile test is proposed through the stress superposition. On this basis, the calculation formula for the indirect tensile strength of the interlaminar bonding is derived according to Tresca’s law. A low-temperature indirect tensile test was designed and conducted to verify the correctness of the formula. By comparing the results of the indirect tensile test and direct tensile test, it is found that the interlaminar strength of the mixture measured by them is similar, and the dispersion of indirect tensile test results is small. The results show that the indirect tensile test can replace the direct tensile test to evaluate the interlaminar tensile strength.
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Jaber, Ali, Iqbal Gorgis, and Maan Hassan. "Relationship between splitting tensile and compressive strengths for self-compacting concrete containing nano- and micro silica." MATEC Web of Conferences 162 (2018): 02013. http://dx.doi.org/10.1051/matecconf/201816202013.
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This paper describes the relationship between splitting tensile strength and compressive strength of self-consolidating concrete using data collected from laboratory specimens tested at standard conditions. The results were then compared with some expressions published in international literature. The investigated variables included: type of cement, percentage of nanosilica and percentage of microsilica as a cement replacement by weight. In spite of concrete not being designed to resist direct tension the knowledge of tensile strength is needed to estimate the cracking load. In the absence of test results an estimate of the tensile strength may be obtained by using the relationship proposed. The verification of the proposed formula based on experimental data was estimated by means of the integral absolute error (IAE). The output of this study has provided a better understanding of the correlation between splitting and compressive strengths of SCCs and the effect of some related variables on the resultant behavior, which has therefore, helped to generate new expression with better accuracy.
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Tüfekci, Kenan, Servet Demirdag, Nazmi Sengun, Tamer Efe, and Rasit Altindag. "An alternative approach to obtaining the direct tensile strength of the rocks from the indirect tensile strength." Pamukkale University Journal of Engineering Sciences 27, no. 6 (2021): 756–65. http://dx.doi.org/10.5505/pajes.2021.98479.
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Heru, Purnomo, Andhika Rizki Yuandry, and Elly Tjahjono. "Direct Tensile Strength of Lightweight Concrete Using Polypropylene Coarse Aggregate Coated with Sand." Key Engineering Materials 789 (November 2018): 131–36. http://dx.doi.org/10.4028/www.scientific.net/kem.789.131.
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Plastic waste used as coarse aggregates in structural concrete is part of efforts to minimizeenvironmental pollution. It can provide lightweight concrete but with a lower strength compared tonormal concrete. Accordingly, an experimental study of 12 concrete specimens using wastepolypropylene coarse aggregates coated with sand was carried out. Direct tensile tests were conductedto cylinder concrete specimens having diameter of 10 cm and depth of 20 cm respectively. Threemixtures of sand coated polypropylene coarse plastic aggregate, river sand as fine aggregate, waterand Portland Composite Cement with a water-cement ratio of 0.286 were conducted. The massproportion of cement and sand are the same but the mass of plastic coarse aggregates coated withsand is specific for each mixture. Direct tensile strength of the specimens in general shows that highertensile strength is found for specimens having higher compressive strength. From the test results, amodel of direct tensile stress-strain relation is proposed. Finally the direct tensile strength forlightweight concrete using polypropylene coarse aggregate coated with sand is found to be lower thanthe direct tensile strength for normal concrete.
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David Suits, L., TC Sheahan, H. Nahlawi, S. Chakrabarti, and J. Kodikara. "A Direct Tensile Strength Testing Method for Unsaturated Geomaterials." Geotechnical Testing Journal 27, no. 4 (2004): 11767. http://dx.doi.org/10.1520/gtj11767.
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Kim, Seungwon, Dong Joo Kim, Sung-Wook Kim, and Cheolwoo Park. "Tensile Behavior Characteristics of High-Performance Slurry-Infiltrated Fiber-Reinforced Cementitious Composite with Respect to Fiber Volume Fraction." Materials 12, no. 20 (October 13, 2019): 3335. http://dx.doi.org/10.3390/ma12203335.
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Concrete has high compressive strength, but low tensile strength, bending strength, toughness, low resistance to cracking, and brittle fracture characteristics. To overcome these problems, fiber-reinforced concrete, in which the strength of concrete is improved by inserting fibers, is being used. Recently, high-performance fiber-reinforced cementitious composites (HPFRCCs) have been extensively researched. The disadvantages of conventional concrete such as low tensile stress, strain capacity, and energy absorption capacity, have been overcome using HPFRCCs, but they have a weakness in that the fiber reinforcement has only 2% fiber volume fraction. In this study, slurry infiltrated fiber reinforced cementitious composites (SIFRCCs), which can maximize the fiber volume fraction (up to 8%), was developed, and an experimental study on the tensile behavior of SIFRCCs with varying fiber volume fractions (4%, 5%, and 6%) was carried out through direct tensile tests. The results showed that the specimen with high fiber volume fraction exhibited high direct tensile strength and improved brittleness. As per the results, the direct tensile strength is approximately 15.5 MPa, and the energy absorption capacity was excellent. Furthermore, the bridging effect of steel fibers induced strain hardening behavior and multiple cracks, which increased the direct tensile strength and energy absorption capacity.
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Han, Seung Ju, Seok Joon Jang, Zhong Jie Yu, and Hyun Do Yun. "Tensile and Cracking Behaviors of Strain-Hardening Cement Composite (SHCC) with Fluosilicate Based Shrinkage-Reducing Agent (SRA)." Applied Mechanics and Materials 525 (February 2014): 473–77. http://dx.doi.org/10.4028/www.scientific.net/amm.525.473.
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This paper provides the results of direct tensile tests for strain-hardening cement composite (SHCC) to investigate the influence of fluosilicate based shrinkage-reducing agent (SRA) on the tensile and cracking behaviors of SHCC material under direct tension. The specified compressive strength of the SHCC material is 50MPa. The adding ratio of fluosilicate based SRA for SHCC material is 2.5 and 5.0%. Two mixitures of SHCC with 2.2% polyvinyl alcohol (PVA) fibers at the volume fraction were mixed; two mixtures with SRA and one mixture of conventional SHCC material. To evaluate the tensile and cracking behaviors of SHCC materials, two dumbbell-shaped tensile specimens for each mixture were manufactured and tested in direct tension. Test results show that the addition of fluosilicate based SRA improved direct tensile and cracking behaviors of SHCC materials with rich mixture. This phenomenon is noticeable for SHCC with higher volume of SRA.
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He, Shixin, Haibo Bai, and Zhiwei Xu. "Evaluation on Tensile Behavior Characteristics of Undisturbed Loess." Energies 11, no. 8 (July 30, 2018): 1974. http://dx.doi.org/10.3390/en11081974.
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Tensile strength is one significant parameter involved in tensile fracture in soil mechanics. In this paper, a stress-controlled, uniaxial, direct-tension test apparatus was developed to investigate the tensile properties of soils. A limited number of investigations have examined the impact of anisotropy and loading interval on the tensile strength of undisturbed loess. The deformation and strains generated were also examined during the tests. It was revealed that anisotropy was an important factor affecting tensile strength of undisturbed loess, and the effect of loading interval on tensile strength significantly depended on water content. It was negligible while the water content was below the plastic limit. However, when the water content was above the plastic limit, the loading interval not only affected the tensile strength, but also the failure displacement and stiffness response of the soil. Two patterns of tensile fracture were summarized and discussed. Moreover, an empirical constitutive relation was proposed to describe the stress-strain relationship of undisturbed loess and its robustness was validated by the experimental data.
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Duan, Junzhou, Yubin Lu, Shu Zhang, and Xiquan Jiang. "Comparative study of tensile tests based on Hopkinson bar for recycled aggregate concrete." International Journal of Protective Structures 10, no. 1 (July 19, 2018): 26–53. http://dx.doi.org/10.1177/2041419618788697.
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To comparatively study the tensile properties and fracture patterns of recycled aggregate concrete with various replacement percentages (i.e. 0%, 25%, 50%, 75%, and 100%) of recycled coarse aggregate, the dynamic direct tensile tests, splitting tests, and spalling tests of recycled aggregate concrete in the strain-rate range of 100–102 s−1 were carried out using large diameter (75 mm) split Hopkinson tensile bar and pressure bar. Test results show that for recycled aggregate concrete, the quasi-static direct tensile strength is more marvelous than its quasi-static splitting strength. When recycled coarse aggregate replacement percentage is 0%–75%, the replacement percentage impact minimally on the quasi-static tensile strength of recycled aggregate concrete. In dynamic tensile tests, there exists apparent difference between the dynamic direct tensile strength and dynamic splitting. The dynamic tensile strength of recycled aggregate concrete increases with the increase of average strain-rate in all three kinds of tests. The average strain-rate affects the damage form of recycled aggregate concrete, which indicates that the recycled aggregate concrete has obvious rate sensitivity. There shows no obvious regularity between the dynamic tensile strength and the recycled coarse aggregate replacement percentage. And the indirect tensile strength calculation method used in this article offers the theoretical basis for the engineering application of recycled aggregate concrete.
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Liu, Yang, Da Huang, Duofeng Cen, Zhu Zhong, Fengqiang Gong, Zhijun Wu, and Yongtao Yang. "Tensile Strength and Fracture Surface Morphology of Granite Under Confined Direct Tension Test." Rock Mechanics and Rock Engineering 54, no. 9 (June 15, 2021): 4755–69. http://dx.doi.org/10.1007/s00603-021-02543-7.
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Al Houri, Ausamah, Ahed Habib, Ahmed Elzokra, and Maan Habib. "Tensile Testing of Soils: History, Equipment and Methodologies." Civil Engineering Journal 6, no. 3 (March 1, 2020): 591–601. http://dx.doi.org/10.28991/cej-2020-03091494.
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Tensile strength of soil is indeed one of the important parameters to many civil engineering applications. It is related to wide range of cracks specially in places such as slops, embankment dams, retaining walls or landfills. Despite of the fact that tensile strength is usually presumed to be zero or negligible, its effect on the erosion and cracks development in soil is significant. Thus, to study the tensile strength and behavior of soil several techniques and devices were introduced. These testing methods are classified into direct and indirect ways depending on the loading conditions. The direct techniques including c-shaped mold and 8-shaped mold are in general complicated tests and require high accuracy as they are based on applying a uniaxial tension load directly to the specimen. On the other hand, the indirect tensile tests such as the Brazilian, flexure beam, double punch and hollow cylinder tests provide easy ways to assess the tensile strength of soil under controlled conditions. Although there are many studies in this topic the current state of the art lack of a detailed article that reviews these methodologies. Therefore, this paper is intended to summarize and compare available tests for investigating the tensile behavior of soils.
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Badarulzaman, Nur Azam, Siti Rodiah Karim, and Mohd Amri Lajis. "Fabrication of Al-Sn Composites from Direct Recycling Aluminium Alloy 6061." Applied Mechanics and Materials 465-466 (December 2013): 1003–7. http://dx.doi.org/10.4028/www.scientific.net/amm.465-466.1003.
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Solid-state direct conversion method of recycled aluminium 6061 alloy to produce metal-metal composites was studied by using collected recycle chip. Different volume percent of stannum (Sn) matrix was studied to attempt the tensile strength and surface integrity of the aluminium composites product. Constant pressure was used to implement the cold forging process with constant sintering temperature. Single size of chip had been used which 2 mm length as suggested. The optimum result of yield strength and ultimate tensile strength is 3 Pa and 8.3 Pa for 20 vol% of Sn composition. Analysis shows that composites beyond 20 vol% Sn resulted in the tensile strength decreased.
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Wasil, Mariola, and Katarzyna Zabielska-Adamska. "Tensile Strength of Class F Fly Ash and Fly Ash with Bentonite Addition as a Material for Earth Structures." Materials 15, no. 8 (April 14, 2022): 2887. http://dx.doi.org/10.3390/ma15082887.
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The behavior of soils under tensile stress is of interest to geotechnical engineers. Tensile strength of soils is often associated with tensile fractures that can generate a privileged flow path. The addition of bentonite improves the plastic properties of the soil, therefore the study was conducted for the compacted class F fly ash and fly ash with various bentonite additions. An amount of bentonite was: 5, 10 and 15%, calculated in weight relation to dry mass of samples. The tensile strength of compacted clay was also established, for comparison. Laboratory tests were carried out using the direct method (breaking) on cylindrical samples and the indirect method (the Brazilian test) on disc-shaped specimens. For this purpose, a universal testing machine with a frame load range of ±1 kN was used. It is stated that bentonite considerably influences the tensile strength of the fly ash evaluated with both methods. The tensile strength values obtained with the Brazilian method are comparable or higher than those obtained with the direct method. The achieved tensile strength values of compacted fly ash, improved by 10−15% of bentonite addition, are comparable with the results obtained for clay used in mineral sealing, while the strain at maximum tensile strength is similar in the direct test and lower in the indirect test.
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Al Zahawi, Serwan. "Impact of Glass Waste on the Flexural, Compressive, and Direct Tension Bonding Strengths of Masonry Bricks." Journal of Engineering 28, no. 11 (November 1, 2022): 85–106. http://dx.doi.org/10.31026/j.eng.2022.11.07.
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The waste material problem in today's world has become a major topic affecting all sectors of human life. Researchers are interested in providing solutions for each kind of waste material. Waste glass is one of the waste materials whose amounts increase daily. This article deals with two types of modified cement mortar with glass granular in the masonry wall to find their effect on the wall's property (direct tensile, flexural, and compressive bond strength). Seven different mixes were prepared according to the used glass granular ratio (three mixes contained white glass with 15, 20, and 25% while three of them contained green glass granular 5, 10, and 15%, and the last mix was a controlled mix which contains no glass granular).Based on the obtained result, the used white glass granular provides optimum compression and direct tensile bond strength when 20% of sand is replaced with white glass granular; optimum direct tensile bond value was obtained, which increased by 1.4% and increased compressive strength by 13.08% compared to control mortar. Green glass granular provides optimum compression and direct tensile bond strength when 10% of sand is replaced, direct tensile strength by 1.02%, and increased compressive strength by 3.7% compared to control mortar. The increase of the used waste glass granular in the mortar decreases flexural bond strength, and the amount of decrease depends on the chemical glass compositions.
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Lin, Wei Ting, Yuan Chieh Wu, An Cheng, and Sao Jeng Chao. "Engineering Properties of Fiber Cementitious Materials." Applied Mechanics and Materials 764-765 (May 2015): 42–46. http://dx.doi.org/10.4028/www.scientific.net/amm.764-765.42.
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Fiber cementitious materials are composed of fibers, pozzolan and cementitious. Addition of fibers in cementitious materials may enhance its mechanical properties, particularly tensile strength, and ductility. This project is aimed to evaluate the mechanical properties of fiber cementitious materials which comprise fibers and silica fume in the mixes. Test variables include dosage of silica fume, mix proportions, steel fiber dosage and type. Compressive strength, direct tensile strength and splitting tensile strength of the specimen were obtained through tests. Test results indicate that the splitting tensile strength, direct tensile strength, strain capacity and ability of crack-arresting increase with increasing steel fiber and silica fume dosages. The optimum composite is the mixture with 5 % replacement silica fume and 2 % fiber volume. In addition, the nonlinear regression analysis was used to determine the best-fit relationship between mechanical properties and test parameters.
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Aljabbri, Noor Alhuda Sami, Mohammed Noori Hussein, and Ali Abdulmohsin Khamees. "Performance of Ultra High Strength Concrete Expose to High Rise Temperature." Annales de Chimie - Science des Matériaux 45, no. 4 (August 31, 2021): 351–59. http://dx.doi.org/10.18280/acsm.450411.
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Fire or high temperature is a serious issue to ultra-high-strength concrete (UHSC). Strength reduction of UHPCs may amount to as high as 80 percent after exposure to 800℃. A sum of four UHSC mixes was synthesized and evaluated in this study after getting exposed to extreme temperatures that reach 1000°C. Steel and polypropylene (PP) fibers were used in this experiment. A total of four mixes were made of UHSC without fibres as a control mix (UHSC-0), UHSC with 2% steel fibres (UHSC-S), UHSC with 2% PP fibres (UHSC-P) and UHSC with 1% steel fibres + 1% PP fibres (UHSC-SP). Workability, direct tensile strength, compressive strength, and splitting tensile strength were examined. Particularly, emphasis was devoted to explosive spalling since UHPCs are typically of compact structure and hence more prone to explosive spalling than other concretes. It was determined that the mixture UHSC-SP had high fire resistance. Following exposure to 1000℃, this mixture preserved a residual compressive strength of 36 MPa, splitting tensile strength of 1.62 MPa and direct tensile strength of 0.8 MPa. On the other hand, UHSC-P also had good fire resistance while UHSC-0 and UHSC-S experienced explosive spalling after heating above 200ᴼC. The incorporation of steel fibers in UHSC-S and UHSC-SP mixtures reveals higher tensile and compressive strength findings at different elevated temperatures as compared to UHSC-0 and UHSC-P. In addition, the result of direct tensile strength appears to be lower than splitting tensile strength at different raised temperatures.
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Hong, Geon-Ho. "Effect of Aspect Ratio in Direct Tensile Strength of Concrete." Journal of the Korea Concrete Institute 15, no. 2 (April 1, 2003): 246–53. http://dx.doi.org/10.4334/jkci.2003.15.2.246.
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Pembele, Wilson, Yilin Gui, and Ross Stirling. "Laboratory Tensile Strength Testing of Clay Soils using Direct Measurement." Japanese Geotechnical Society Special Publication 7, no. 2 (April 30, 2019): 198–204. http://dx.doi.org/10.3208/jgssp.v07.030.
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Huang, Zhengjun, Ying Zhang, Yuan Li, Dong Zhang, Tong Yang, and Zhili Sui. "Determining Tensile Strength of Rock by the Direct Tensile, Brazilian Splitting, and Three-Point Bending Methods: A Comparative Study." Advances in Civil Engineering 2021 (June 2, 2021): 1–16. http://dx.doi.org/10.1155/2021/5519230.
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To accurately obtain the tensile strength of rock and fully understand the evolution process of rock failure is one of the key issues to the research of rock mechanics theories and rock mass engineering applications. Using direct tensile, Brazilian splitting, and three-point bending test methods, we performed indoor and numerical simulation experiments on marble, granite, and diabase and investigated the tensile strength and damage evolution process of several typical rocks in the three different tests. Our experiments demonstrate that (1) the strength is about 10% greater in the Brazilian splitting than in the direct tensile, while the tensile modulus is lower; it is the highest in the three-point bending, which is actually subjected to the bending moment and suggested as one of the indexes to evaluate the tensile strength of rock; (2) the strength in splitting tests is strikingly different, while the strain law is basically similar; the direct tensile test with precut slits is more attainable than that with no-cut slits, with an uninfluenced strength; (3) the failure modes of rocks using different methods are featured by different lithology, while their final modes are basically the same under the same method; (4) PFC and RFPA numerical simulation tests are effective to analyze the internal crack multiplication and acoustic emission changes in the rock as well as the damage evolution process of rock in different tests.
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Li, Yue Wen, and Xin Hua Chen. "Direct Reactive Compatibilization of GMA on PE/Wood-Flour Composite." Advanced Materials Research 378-379 (October 2011): 735–39. http://dx.doi.org/10.4028/www.scientific.net/amr.378-379.735.
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Reactive compatibilization between high-density polyethylene(HDPE) and wood-flour was achieved via direct reactive extrusion of glycidyl methacrylate(GMA), initiator, HDPE and wood-flour. Impact rupture surface of the composite was observed by scanning electron microscope(SEM), and its load deformation temperature(HDT) and mechanical properties were tested. Effect of GMA dosage and extrusion temperature on reactive compatibilization of the composite was analysed. The result indicated that the anchoring strength of interface in the composite was obviously strengthened, and its HDT, tensile strength, flexural strength, notched impact strength and elongation at break of the composite were distinctly improved due to the addition of GMA and dicumyl peroxide(DCP). When the composite was extruded at 180°C, the peak values of its HDT, tensile strength, flexural strength, elongation at break and notched impact strength respectively were 84°C, 40Mpa, 45Mpa, 11% and 6.6KJ.m-2, which respectively increased by 17°C, 74%, 36%, 83% and 69% than that of the composite without reactive compatibilization, and when the composite was extruded at 190°C, the peak values of its HDT, tensile strength, flexural strength, elongation at break and notched impact strength respectively were 84°C, 40Mpa, 44Mpa, 11% and 6.6KJ.m-2, which respectively increased by 20°C, 60%, 26%, 83% and 83% than that of the composite without reactive compatibilization. When GMA usage increased, the HDT and mechanical properties of the composite increased first, then descended, and the optimum usage of GMA was 1wt%-3wt%.
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Li, Yue Wen, and Xin Hua Chen. "Study on Direct Reactive Compatibilization of HDPE/Wood-Flour Composites." Advanced Materials Research 239-242 (May 2011): 2346–51. http://dx.doi.org/10.4028/www.scientific.net/amr.239-242.2346.
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Reactive compatibilization between high-density polyethylene(HDPE) and wood-flour was achieved via direct reactive extrusion of maleic anhydride(MAH), initiator, HDPE and wood-flour. Impact rupture surface of the composites was observed by scanning electron microscope(SEM), and its load deformation temperature(HDT) and mechanical properties were tested. Effect of MAH dosage, initiator activity and extrusion temperature on the reactive compatibilization was analysed. The result indicated that the anchoring strength of interface in the composites was obviously strengthened and its HDT, tensile strength, flexural strength, notched impact strength and elongation at break were distinctly improved due to the addition of MAH and dicumyl peroxide(DCP). When the composites were extruded at 180°C, the peak values of its HDT, tensile strength, flexural strength, elongation at break and notched impact strength respectively were 79°C, 34Mpa, 36Mpa, 30% and 10KJ.m-2, which respectively increased by 10°C, 62%, 33%, 200% and 150% than that of the composites without reactive compatibilization, and when the composites were extruded at 200°C, the peak values of its HDT, tensile strength, flexural strength, elongation at break and notched impact strength respectively were 78°C, 34Mpa, 36Mpa, 24% and 8KJ.m-2, which respectively increased by 12°C, 55%, 33%, 200% and 100% than that of the composites without reactive compatibilization. In the case of DCP and MAH as compatibilizer, there was an optimum dosage of MAH. The optimum dosage was shifted forward as extrusion temperature increased.
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Heins, Kira, Magdalena Kimm, Lea Olbrueck, Matthias May, Thomas Gries, Annette Kolkmann, Gum-Sung Ryu, Gi-Hong Ahn, and Hyeong-Yeol Kim. "Long-Term Bonding and Tensile Strengths of Carbon Textile Reinforced Mortar." Materials 13, no. 20 (October 10, 2020): 4485. http://dx.doi.org/10.3390/ma13204485.
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This paper deals with the long-term bonding and tensile strengths of textile reinforced mortar (TRM) exposed to harsh environments. The objective of this study was to investigate the long-term bonding and tensile strengths of carbon TRM by an accelerated aging method. Moisture, high temperature, and freezing–thaw cycles were considered to simulate harsh environmental conditions. Grid-type textiles were surface coated to improve the bond strength with the mortar matrix. A total of 130 TRM specimens for the bonding test were fabricated and conditioned for a prolonged time up to 180 days at varying moisture conditions and temperatures. The long-term bonding strength of TRM was evaluated by a series of bonding tests. On the other hand, a total of 96 TRM specimens were fabricated and conditioned at freezing–thaw conditions and elevated temperature. The long-term tensile strength of TRM was evaluated by a series of direct tensile tests. The results of the bonding test indicated that TRM was significantly degraded by moisture. On the other hand, the influence of the freezing–thaw conditions and high temperature on the tensile strength of the TRM was insignificant.
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Taiyab, Abu, Nazmun Islam, and Mokhlesur Rahman. "Desiccation characteristics and direct tension attributes of thin clayey soil containing discrete natural fibers." Soils and Rocks 45, no. 4 (September 21, 2022): 1–13. http://dx.doi.org/10.28927/sr.2022.074421.
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The use of thin clayey soil as a liner plays an important role in many geotechnical and geo-environmental engineering applications, such as open channel and reservoir sealant, contaminant barrier etc. Their functional performance and sustainability depend primarily on the desiccation characteristics of these liners and barriers. A number of studies have been undertaken to quantify the degree of improvement achieved by using natural and synthetic fiber reinforcement. However, there is a lack of studies to understand the desiccation behavior of reinforced clay. This study aimed to explore the desiccation and cracking behavior of clayey soil reinforced with two natural fibers (coir and jute fiber) in addition to the degree of improvement in tensile strength. A series of direct tension and desiccation cracking tests have been conducted in the laboratory on clay-coir and clay-jute fiber mixes. The results demonstrate that when coir and jute fibers are used, the tensile strength of fiber-reinforced soil rises by up to 475 percent and 215 percent, respectively, when compared with the tensile strength of unreinforced soil at the same moisture content. Desiccation test results also show that blending of fibers reduces the breadth and depth of cracks significantly. The characteristics of unreinforced and fiber-reinforced clayey soil under desiccation and direct tension are briefly discussed in this paper. Findings of the present study will be important for professionals dealing with clay liners and trying to reduce cracking problems associated with drying soil.
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Wang, Ru, Chun An Tang, Shu Hong Wang, Zhi Yuan Wang, and Tian Hui Ma. "Influence of Different Loading Modes on Rock Tensile Strength." Key Engineering Materials 353-358 (September 2007): 2553–56. http://dx.doi.org/10.4028/www.scientific.net/kem.353-358.2553.
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A typical mechanical character of rock is that the tensile strength is far less than the compressive strength. Meanwhile, the test data of tensile strength is very dispersive. Because the direct tensile tests always result in failure due to the difficulty in clamping the rock sample, the splitting test is used to determine the tensile strength of rock. There are four kinds of loading modes in the splitting test in actual laboratory test: angle pad splitting, round pad splitting, aclinic loading platen splitting, arc loading platen splitting. In this paper, the direct tensile test, the splitting test and the influence of different loading modes on rock tensile strength were studied. In order to study the stress distribution, the progressive splitting failure process was numerically modeled under the four kinds of loading cases by the Realistic Failure Process Analysis code (RFPA2D). Results show that the stress states under angle pad splitting, round pad splitting are similar to the stress states under diametrical compressive state. Regarding that the round pad splitting test is easy to implement, and its numerical results are also stable relatively, the round pad loading mode was suggested to be adopted.
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Madhlom, Shahad Q., Hussein A. Aziz, and Ammar A. Ali. "Direct Shear Strength of RPC Member." Engineering and Technology Journal 39, no. 1A (January 25, 2021): 22–33. http://dx.doi.org/10.30684/etj.v39i1a.1638.
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In this research paper, results are obtained from Reactive Powder Concrete (RPC) push-off specimens - double L shape subjected to direct shear loading. Different parameters considered are compressive strength, percentages of steel fiber, presence of aggregate and shear reinforcement. The results show that increasing in steel fiber content starting from 0.0% and ending with 1.5% leads to increases in the shear strength by (261%) and attempt to decrease its brittleness. The presence of steel fiber content enhances and improves the tensile strength and the shear strength. Using RPC in constructing the specimens enhances the shear strength by 29.6% compared with NSC specimen. Shear strength increased by 25% when the compressive strength increased from 75 to 90MPa. The presence of transverse steel rebar in the direction of shear line increased the shear strength by (108.3%) as compare with the specimen without shear rebar. The presence of small aggregate in RPC mix creates an increase in the shear strength by (9.1%).
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Kuddus, Suriyanti, Mohammad Sukri Mustapa, Mohd Rasidi Ibrahim, Shazarel Shamsudin, Muhammad Irfan Ab Kadir, and Mohd Amri Lajis. "Microstructures and Tensile Characteristics on Direct Recycled Aluminium Chips AA6061/Al Powder by Hot Pressing Method." Materials Science Forum 909 (November 2017): 9–14. http://dx.doi.org/10.4028/www.scientific.net/msf.909.9.
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This research aims to investigate the effect on tensile strength of the recycled chip AA6061 aluminium alloy metal by using powder metallurgy method. Material used is recycled aluminium Chip AA6061 and Al powder. The recycled AA6061 chips mixed together with various compositions of Al powder content were fabricated to form a specimen by hot compaction technique. The compaction using hot pressed at 30 tons with holding time of 60 minutes. The final product was analyzed by tensile test shown the specimen A5 have higher ultimate tensile strength (UTS) 156.404 MPa and yield strength (YS) at 107.399 MPa. Scanning Electron Microscopy (SEM) was conducted to observe the microstructure of fracture surface existing on the tensile specimens.
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Sarasook, Prattakon, Putinun Uawongsuwan, Anin Memon, and Hiroyuki Hamada. "Jute Fiber Reinforced Thermoplastic Composites Fabricated by Direct Fiber Feeding Injection Molding (DFFIM) Process." Key Engineering Materials 856 (August 2020): 268–75. http://dx.doi.org/10.4028/www.scientific.net/kem.856.268.
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In this research, jute fiber reinforced polypropylene and poly (lactic acid) composites were fabricated, respectively by Direct Fiber Feeding Injection molding (DFFIM) process. Jute spun yarns were directly fed into the barrel of molding process in order to eliminate the fiber breakage during extrusion compounding process. Mechanical properties of both composites were investigated by tensile testing and morphological properties were characterized by scanning electron microscopy (SEM). For jute reinforced polypropylene (PP) composites, tensile strength of composite decreased but modulus increased, compared with neat PP. The using maleic anhydride grafted polypropylene (MaPP) can improve interfacial bonding between jute fiber and PP matrix as observed by SEM, which resulted in the increasing of tensile strength. Therefore, in the case of jute/PLA composites, jute fibers surface treated with sodium hydroxide (NaOH) and silane coupling agent to improve interfacial adhesion. The tensile strength of untreated-jute/PLA composites are not different with PLA matrix but tensile modulus of untreated composites are higher than PLA matrix. In addition it is found that the tensile properties of NaOH-treated jute/PLA and NaOH+Silane-treated jute/PLA composites were improved, compared with untreated composites.