YURDAKUL, Arife Dumlupinar University - Graduate School of Sciences - Materials and Ceramic Engineering Department, Turkey , GÜNKAYA, Göktuğ Anadolu University - Faculty of Fine Arts - Department of Glass, Turkey , KAVAS, Taner Afyon Kocatepe University - Engineering Faculty - Materials Science and Engineering Department, Turkey , DÖLEKÇEKİÇ, Emrah Anadolu University - Engineering Faculty - Materials Science and Engineering Department, Turkey , KARASU, Bekir Anadolu University - Engineering Faculty - Materials Science and Engineering Department, Turkey

Electron Microscopy Observations on Glass Fiber Reinforced Concrete (GFRC) Materials

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Doping concrete structure with glass fibers gives rise to superior mechanical and chemical properties in macro-scale constructional applications. This type of materials is also currently called a generic name: Glass Fiber Reinforced Concrete (GFRC). Despite the fact that numerous studies have been conducted to shed light on the structure-property relationship in GFRC materials, focusing on the microscopic features to gain a better understanding of fibers role in the concrete matrix is still a challenging task. The goal of present research is, therefore, to reveal the micro-scale behavior of commercially available glass fibers in resulting concrete structures through a scanning electron microscopy (SEM) technique. For this purpose, the fracture surfaces of GFRC samples were characterized using a high-resolution field emission scanning electron microscope (FESEM, Carl Zeiss Supra 50VP) equipped with an energy dispersive X-ray spectrometer (EDXS, Oxford Instruments 7430), operating at 30 kV in variable pressure (VP) mode. The back scattered electron (BSE) showed the general microstructure of GFRC material. As a result of this, the random distribution of Zr-rich glass fibers in mainly calcium-based silicate concrete matrix phases was clearly disclosed, which can be also confirmed by the EDX analysis. In addition, loose structure between the glass fiber and matrix phases was also observed. In fact, this unexpected micro-structural evolution can be considered as an apparent evidence of hydrophobic tendency of very thin polymer coating existing on the fibers’ surface determined with non-microscopic techniques, e.g., simultaneous differential thermal analysis (DTA)/thermal gravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR).

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GFRC , Investigation , Structure , SEM

Afyon Kocatepe University Journal Of Science an‎d Engineering

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