Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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Subject: search.filters.subject.Fiber-reinforced concrete

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Now showing 1 - 5 of 5
  • Master Thesis
    Structural Behavior of Hybrid Fiber Reinforced Concrete Panels Under Blast Loads
    (01. Izmir Institute of Technology, 2021) Alkabbani, Mouhammed Jalal; Saatcı, Selçuk; Saatçi, Selçuk; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Terrorist attacks cause injuries and casualties not only due to direct effect of explosions, but also due to collapse of non-structural elements in buildings such as brick walls. Strengthening of non-blast resistant buildings to blast loads can be done using blast resistant cladding. In this study, structural behavior of panels manufactured using hybrid fiber reinforced concrete, composed of steel and synthetic polyvinyl alcohol (PVA) fibers, under blast loads was investigated and the potential use of such panels for the strengthening of existing buildings against blast loads was examined. For this purpose, 11 panels with 1900x1900x50 dimensions were tested under blast loads. Blast loads were applied on panels by a shock tube designed and manufactured within this project. As a result of the study, it was found that panels manufactured using hybrid fiber reinforced concrete had higher strength and energy absorption capacity under blast loads compared to panels manufactured by using steel fibers only. Using steel and PVA fibers provided a better control of micro and macro cracking and increased the panels' ductility. The study showed that hybrid fiber reinforced concrete panels can be used as a protective cladding for blast loads.
  • Master Thesis
    Bending Behavior of Hybrid Fiber Reinforced Concrete Beams
    (Izmir Institute of Technology, 2020) Aloui, Sarra; Saatcı, Selçuk; Aloui, Sarra; Saatçi, Selçuk; 03.03. Department of Civil Engineering; 01. Izmir Institute of Technology; 03. Faculty of Engineering
    Fiber reinforced concrete is widely used in various applications in concrete members. In this study, effect of fiber hybridization, using different types of fibers in concrete mix, on the bending behavior of concrete beams was investigated. For this purpose, eight beam specimens, 2500x500x50 mm in dimension, were cast in pairs with four different steel fiber content. One of the two specimens with the same steel fiber content had additional Polyvinyl Alcohol (PVA) fibers. The specimens were first tested under three-point bending. After these tests, failed specimens, which had a single crack at the midspan, were broken into two halves and the half with no visible damage was tested again under four-point loading to obtain the behavior for a constant moment region.The ultimate strength and the load-displacement behaviorwas investigated for each specimen. It was seen that fiber hybridization obtained by addition of PVA had an adverse effect for three-point bending tests. Specimens with additional PVA fibers had a lower ultimate load and deflection capacity compared to specimens with only steel fibers. However, fiber hybridization had a positive effect for same specimens under four-point bending test. It was concluded that hybridization of steel and PVA fibers had a positive effect on the bending behavior for loading conditions that result in a uniform moment distribution. However, for cases where a single crack dominates the behavior, such as a three-point bending case, hybrid fibers were not as effective or even had an adverse effect.
  • 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 Engineering
    Hybrid 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 Technology
    Using 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.
  • Master Thesis
    Impact Resistance of Steel Fiber Reinforced Concrete Slabs
    (Izmir Institute of Technology, 2015) Yaşayanlar, Süleyman; Saatcı, Selçuk; Saatcı, Selçuk; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    As rare as it may seem, impact loads can act on a structure in its lifespan. For structures such as nuclear energy facilities, industrial facilities, and military buildings design for impact loads may be required. Steel fibers are increasingly used in the design and construction of such reinforced concrete structures. However, studies on the effect of steel fibers on the impact resistance of reinforced concrete structures are rare in the literature. This study investigates the global behavior of reinforced concrete slabs with different ratios of steel fibers under static and impact loading. 10 steel fiber reinforced concrete slabs with dimensions of 2150x2150x150 mm were tested with varying steel fiber volume ratios of 0.5 %, 1.0 % and 1.5 %. Specimens were manufactured as twins, as one to be tested under static loading and one to be tested under impact loading. Static tests were carried out by applying a static load at the midpoint with a hydraulic jack, whereas impact tests were applied through free falling drop-weights. Observed behavior and collected data were compared with companion studies of Batarlar (2013) and Arsan (2014), as they have used the same test setup with different parameters. As a result, it was seen that even steel a fiber addition of 0.5 % in volume was sufficient to provide a ductile behavior both under static and impact loading. Steel fibers significantly enhanced the impact behavior by increasing the strength and resiliency of the specimens.