Yazar "Benlioglu, Arif" seçeneğine göre listele

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    Assessment of Colemanite Waste in Hybrid Fiber-Reinforced Mortars Exposed to Elevated Temperatures
    (Springer Heidelberg, 2025) Altun, Muhammet Gokhan; Benlioglu, Arif; Ozen, Suleyman
    This study systematically investigates the effects of colemanite waste and hybrid fibers on the high-temperature performance of cementitious mortars, aiming to mitigate the negative impact of colemanite waste on mechanical properties through the use of various fibers, both individually and in hybrid combinations, and thereby providing critical insights for sustainable construction materials. In the study, cement was used as the binder, with colemanite waste substituted at rates of 3, 5, and 7%. Standard sand was used as aggregate, and fibers were incorporated at a volume of 0.4% each of steel fiber, basalt fiber, polypropylene fiber, as well as hybrid fibers (0.2% steel + 0.2% basalt and 0.2% steel + 0.2% polypropylene). The compressive strength, flexural strength, and water absorption rates of the produced mixtures were determined at 7 and 28 days. Additionally, to assess the mechanical performance of the mixtures under high-temperature effects, the 28-day mixtures were exposed to temperatures of 300 and 600 degrees C, and residual compressive and flexural strengths were evaluated. The results indicate that the use of fibers, whether separately or in hybrid forms, enhances the mechanical properties, water absorption capacities, and high-temperature performance of the mixtures, regardless of the substitution ratio of colemanite waste. Among the mortars subjected to high temperatures, the sample containing 7% colemanite waste exhibited the lowest results, whereas the sample, which contained 3% colemanite waste and 0.4% steel fibers, yielded the best results.
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    Effect of graphene oxide-coated jute fiber on mechanical and durability properties of concrete mixtures
    (Elsevier Sci Ltd, 2024) Ozen, Suleyman; Benlioglu, Arif; Mardani, Ali; Altin, Yasin; Bedeloglu, Ayse
    Various methods are applied in order to improve the mechanical properties of concrete and to provide ductility. The most common method is the addition of fiber to cementitious systems. The fibers used in cementitious systems are divided into two categories: artificial and natural. Natural fibers are preferred due to their lower production cost, lower environmental impacts such as lower carbon emissions and fossil fuel consumption, biodegradability, lower density and ease of manufacturing. On the other hand, graphene-derived materials have been proven to improve the mechanical and interface properties between fiber and matrix. In this study, the effect of surface treatment of jute fibers with various chemical treatments and graphene oxide coating on the mechanical and some durability performances of concrete mixtures was investigated. For this purpose, the surface of jute fibers was roughened with graphene oxide coating. Within the scope of the experimental study, different fiber concrete mixtures were prepared by adding jute fibers of 30 and 50 mm length to the mixture at 0.25 and 0.5 % of the total volume in addition to the fiber-free control mixture. The fiber was used in 2 different ways, both without any treatment and by coating the surface with graphene oxide. Slump tests were performed on the concrete mixtures produced. The 28-day hardened concrete specimens were tested for compressive strength, flexural strength, modulus of elasticity, ultrasonic pulse velocity and depth of water penetration under pressure. The resistance of the concrete specimens at 300 and 600 degrees C high temperatures and after 300 cycles of freeze-thaw was determined by examining their compressive strength. In addition, the microstructural properties of the jute fiber specimens were examined using Scanning Electron Microscopy (SEM).
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    High-temperature and drying shrinkage behavior of mortars containing colemanite and different fiber types with air-entraining admixture
    (Taylor & Francis Ltd, 2025) Benlioglu, Arif; Ozansoy, Ayse Irem; Ozen, Suleyman
    In recent years, the construction industry has become a major source of global greenhouse gas emissions, primarily because of the energy-intensive process of cement production. Turkey holds about 73% of the world's boron reserves, providing a significant opportunity to use boron-containing minerals such as colemanite as alternative binders. In this study, mortar mixtures were developed incorporating colemanite, air-entraining admixtures (AEAs), and various fiber types (steel, basalt, carbon and polypropylene). The AEA was used at 0.1% of cement weight, while colemanite replaced 3% and 5% of the cement, and each fiber type was added at 0.5%. The results indicated that mixtures containing 3% and 5% colemanite with steel fibers exhibited the highest performance after thermal exposure, showing up to 130% higher residual compressive strength and 60% higher flexural strength compared to the reference mixture. Moreover, the inclusion of colemanite and fibers generally reduced drying shrinkage, while their combined use significantly enhanced the high-temperature and shrinkage resistance of cement-based mortars. In contrast to previous studies, this work emphasizes the eco-friendly use of colemanite as a partial cement replacement and its synergy with fibers and an AEA, offering practical potential for sustainable and heat-resistant construction materials.
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    Influence of waste aggregate type on the mechanical strength and durability of slag-rice husk ash-based geopolymer composites
    (Taylor & Francis Ltd, 2025) Benlioglu, Arif; Demirel, Mertcan; Altun, Muhammet Gokhan; Ozen, Suleyman
    This study explores the utilization of construction and demolition waste (CDW), ceramic waste (CW), and marble waste (MW) as partial sand replacements in geopolymer mortars produced with granulated blast furnace slag (GBFS) and rice husk ash (RHA). Mortars were prepared with 75% GBFS and 25% RHA, activated using sodium silicate and 12 M sodium hydroxide, and cured at ambient conditions for 28 days. Waste aggregates were substituted at 10%, 20%, and 30%, while mix ratios were kept constant. Hardened properties, drying shrinkage, and high-temperature performance (300 and 600 degrees C) were evaluated, alongside microstructural analyses (X-ray diffraction, scanning electron microscopy, thermogravimetric analysis/derivative thermogravimetric). Results showed MW10 achieved the highest compressive strength with an increase of 27%, while CW20 exhibited the best flexural strength with an increase of 8%. CW and MW reduced drying shrinkage, whereas CDW increased it and caused significant strength loss at elevated temperatures. Combining waste aggregates with industrial by-products boosts sustainability and performance.