scholarly journals Influence of the Modulus of Elasticity of CFRPs on the Compressive Behavior of Confined Test Pieces and on the Flexural Behavior of Short Concrete Beams

2021 ◽  
Vol 11 (2) ◽  
pp. 491
Author(s):  
Daniela Brizuela Valenzuela ◽  
María de las Nieves González García ◽  
Alfonso Cobo Escamilla

In this study, we compare the behavior of confined compression-tested concrete test pieces and short concrete beams subjected to three-point flexural strength testing when they are reinforced with high-modulus, high-strength carbon fibers reinforced polymers (CFRP). The fabrics used have roughly the same mechanical capacity but very different rigidities. As such, the results make it possible to obtain the influence of the rigidity of the CFRP on the structural behavior of the elements tested. The results obtained show that the type of fabric used does not cause significant differences in the values of tension of rupture and the form of rupture of the test pieces subjected to compression and flexural strength testing, which suggests that the variable which determines the mechanical response of the elements which have been reinforced and subjected to these kinds of demands is the mechanical capacity of the reinforcement, not its rigidity.

2013 ◽  
Vol 680 ◽  
pp. 230-233 ◽  
Author(s):  
Yong Taeg Lee ◽  
Seung Hun Kim ◽  
Jong Hyeon Kim ◽  
Sang Ki Baek ◽  
Young Sang Cho ◽  
...  

Recently, many structures which were built about 30 years ago are watched by reconstruction. Demolished concrete is occurred in the process and these quantity increase about 10% more than the preceding year. Fortunately, recycled aggregates are produced from demolished concrete, whereas the recycled aggregates are not used often because there are not many researches which have been verified by experts or researchers about strength when reinforced concrete is made with recycled aggregates. In this paper, high strength reinforced concrete is valued with potential applications and check change of strength when it made by recycled aggregates. For this, flexural tests of 4 high strength reinforced concrete beams with recycled aggregates were performed, and the high strength reinforced concrete beams were tested within the limits such as compressive strength, flexural strength, ductility, strain, and curvature. The current test data were examined in terms of flexural strength, along with the data from previously tested reinforced concrete beams with recycled aggregates.


2018 ◽  
Vol 161 ◽  
pp. 587-597 ◽  
Author(s):  
Haitang Zhu ◽  
Shengzhao Cheng ◽  
Danying Gao ◽  
Sheikh M. Neaz ◽  
Chuanchuan Li

2019 ◽  
Vol 9 (6) ◽  
pp. 1241 ◽  
Author(s):  
Seung-Jung Lee ◽  
Doo-Yeol Yoo ◽  
Do-Young Moon

This study investigates the effects of hooked-end fiber geometry and volume fraction on the flexural behavior of concrete pedestrian decks. To achieve this, three different fiber geometries, i.e., three-dimensional (3D), four-dimensional (4D), and five-dimensional (5D), and volume fractions of 0.37%, 0.6%, and 1.0% were considered. Test results indicate that a higher number of hook ends can more effectively enhance the flexural strength and flexural strength margin at all volume fractions than a lower number, so that the order of effectiveness of hooked-end fibers on the flexural strength parameters was as follows: 5D > 4D > 3D. To satisfy the ductility index of 0.39, the amounts of 3D, 4D, and 5D hooked steel fibers should be in the range of 0.98%‒1.10%. Moreover, at a fiber volume fraction of 1.0%, only multiple cracking behaviors were observed, and the numerical results indicated that the volume fraction should be equal to 1.0% to guarantee a deflection-hardening response of pedestrian decks, regardless of the hooked-end fiber geometry. Consequently, a 1.0% by volume of hooked-end steel fiber is recommended to replace the minimum longitudinal steel rebars and guarantee a ductile flexural behavior with multiple cracks for pedestrian decks made of high-strength concrete.


2013 ◽  
Vol 5 (2) ◽  
pp. 76-81 ◽  
Author(s):  
Edgaras Atutis ◽  
Juozas Valivonis ◽  
Mantas Atutis

The current economic pressures on utilities to extend a service life of structural concrete mean that concrete structures may have to perform safety functions for a time period significantly greater than their initial design life. However, the structural design and construction requirements for concrete structures with non-metallic reinforcement are very unique and not complete. This paper aims to provide experimental investigations of concrete beams reinforced with GFRP (glass fibre reinforced polymers) based on flexural strength. Both reinforced and prestressed concrete beams have been tested. Together with the strength characteristics, the effect of pre-stress on deflection and cracking distribution has been mainly governed by the stress–strain laws of reinforced concrete. The work is resulted in design code equations for the prediction of the ultimate flexural strength. The influence of the effect of prestressing on the deflection and cracking was analysed. Santrauka Dėl dabartinės ekonominės situacijos vis labiau siekiama, kad konstrukcinis betonas būtų naudojamas kuo ilgiau. Ypač su sauga susijusioms gelžbetoninėms konstrukcijoms dažnai keliami reikalavimai, kad per eksploatacinį šių konstrukcijų laikotarpį pagrindinės betono savybės liktų nepakitusios, lyginant su projektinėmis vertėmis. Vis dėlto reikalavimai, keliami šių konstrukcijų eksploatavimui, yra unikalūs, tačiau nėra visiškai apibrėžti. Straipsnyje aprašomi sijų, armuotų stiklo pluošto armatūra, eksperimentiniai tyrimai, kuriuose buvo nagrinėjama šių sijų laikomoji galia statmenajame pjūvyje. Buvo bandomos sijos, armuotos išilgine iš anksto įtempta stiklo pluošto armatūra, ir sijos, armuotos neįtemptąja stiklo pluošto armatūra. Gautos statmenojo pjūvio laikomosios galios lyginamos su įvairiomis projektavimo normomis ir rekomendacijomis, analizuojama išankstinio įtempimo reikšmė sijų įlinkiui bei pleišėtumui.


2014 ◽  
Vol 601 ◽  
pp. 203-206 ◽  
Author(s):  
Lluís Gil ◽  
Christian Escrig ◽  
Ernest Bernat-Maso

This work presents a method of strengthening concrete structures based on textiles of high strength and mortars. The combination of textiles and mortars produces a new composite material with cementitious matrix. This material can be used for the reinforcement of concrete beams under bending loads. We tested several combinations of fibers: glass, Poliparafenil Benzobisoxazol (PBO), steel and carbon fibers with mortar and we used them to reinforce precast concrete beams. All the specimens were tested with a four-point load test. We discuss the performance of the specimens and we compare the ultimate results with the formulae from FRP codes.


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