Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Punching Behavior of Hybrid Fiber Reinforced Concrete Panels(01. Izmir Institute of Technology, 2020) Naseri, Jamalullah; Saatcı, Selçuk; Saatçi, Selçuk; 03.03. Department of Civil Engineering; 01. Izmir Institute of Technology; 03. Faculty of EngineeringHybrid fiber reinforced concrete (HyFRC) is a more recent type of fiber reinforced concrete (FRC), which includes two or more different fibers types. HyFRC may result in a multifunctional material due to synergetic effects of the various type of fibers added in the mixture. In this study, punching behavior of HyFRC thin panels using three different types of steel fibers and polyvinyl alcohol (PVA) fibers were experimentally investigated. In total 13 panel specimens were cast with dimensions of 1700 x 1700 mm2 and thickness of 50 mm. The specimens were simply supported along the edges and loaded through a 150 mm circular steel plate at the center by a displacement-controlled hydraulic actuator. A load cell and fifteen displacement transducers were used to measure the applied load and vertical deflection of the specimens, respectively. All specimens that contained only steel fibers failed under punching. In hybrid fiber reinforced specimens with steel and PVA fibers, either a flexural failure or a punching failure followed by significant flexural deformations were observed. Test results confirm that fiber reinforced concrete has a very significant effect on thin panel's punching strength and displacement capacity. It was seen that hybridization of two different types of fiber, steel and PVA fibers, brings advantages in terms of punching load capacity, deformation characteristics and failure mode.Master Thesis Mechanical Behavior of Hybrid Fiber Reinforces Concrete Under Direct Tension(Izmir Institute of Technology, 2020) Çetin, Fatma Şirin; Saatcı, Selçuk; Erdem, Tahir Kemal; Saatçi, Selçuk; Erdem, Tahir Kemal; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyUsing different fiber types together, called hybrid fiber reinforced concrete, may cause a mutual synergic response between fiber matrixes. Due to these synergic effects of different fiber combinations, the mechanical behavior of concrete may perform differently than single fiber reinforced concrete. In this study, the effects of fiber hybridization in the direct tension behavior of concrete mixtures obtained by using three different types of steel fiber and polyvinyl alcohol (PVA) fiber were investigated. In this scope, total of 50 dog bone shaped, notched specimens were cast for 10 different mixtures and tested under direct tension. Average tensile stress-crack width responses of concrete specimens were investigated. It was found that the addition of PVA fiber to 35 mm long single hook end and 60 mm long double hook end steel fiber mixtures with a volume ratio of 0.75% did not considerably change the tensile behavior post cracking. As a result of adding PVA fibers to 60 mm single hook steel fiber mixtures with a volume ratio of 1.25%, cracking stresses were decreased and post cracking behavior was adversely affected. Addition of PVA fibers to 60 mm single hook steel fiber mixture with 0.75% volumetric ratio was found to increase post cracking stress levels.