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Öğe Engineering properties and thermal conductivity of lightweight concrete with polyester-coated pumice aggregates(De Gruyter Poland Sp Z O O, 2025) Tuncer, Metin; Bideci, Alper; Bideci, Ozlem Salli; Comak, Bekir; Durmus, GokhanPumice aggregates stand out with their low density and high porosity. However, their high water retention capacity and low mechanical strength are the primary disadvantages limiting their use in lightweight concrete production. In this study, pumice aggregates with particle sizes ranging from 4 to 16 mm were coated with polyester, known for its superior adhesion and insulation properties, to produce polyester-coated pumice aggregates. Subsequently, five different lightweight concrete mixtures were prepared using 450 kg/m(3) cement, incorporating coated and non-coated pumice aggregates as coarse aggregates at replacement ratios of 0, 25, 50, 75, and 100%. Aggregate tests included specific gravity and water absorption, while fresh concretes were evaluated for unit weight and slump. Hardened concretes were tested for dry unit weight, water absorption, ultrasonic pulse velocity (UPV), compressive strength, freeze-thaw resistance, and thermal conductivity. The results revealed that the polyester coating increased the specific gravity of pumice aggregates by up to 45% and reduced water absorption by 85%. The use of coated aggregates increased the unit weight of the concrete but resulted in a reduction in compressive strength and UPV. Despite a compressive strength reduction of up to 58% depending on the coated aggregate content, concrete specimens produced with polyester-coated aggregates exhibited the highest performance in terms of freeze-thaw resistance and thermal conductivity.Öğe Experimental Investigation of Durability Properties of Polymer Coated Pumice Aggregate Lightweight Concretes(Mdpi, 2025) Tuncer, Metin; Bideci, Alper; Comak, Bekir; Durmus, Goekhan; Bideci, Ozlem SalliPumice aggregates with low density and high porosity are widely used in lightweight concrete. The high water retention ability of pumice aggregates adversely affects the properties of fresh concrete. Additionally, pumice aggregates' inadequate mechanical strength and durability hinder concrete performance. In recent years, research on coated aggregates has gained traction to improve the physical properties, mechanical strength, and durability characteristics of concrete. In this study, coarse pumice aggregates were coated with polyester and partially substituted with uncoated aggregates at ratios of 0%, 25%, 50%, 75%, and 100% in lightweight concrete formulations. Specific weight and water absorption tests were performed on the aggregates, while slump and unit weight tests were performed on fresh concrete mixtures. SEM-EDX analyses, unit weight, water absorbing capacity, sorptivity, compressive strength, freeze-thaw resistance, and sulfate resistance tests were performed on concrete specimens. The results indicated that the polyester coating significantly increased the specific weight of the aggregates and decreased the water absorption rates by up to 85%. Despite the coated aggregates resulting in decreased compressive strength of concrete specimens, they demonstrated reduced water absorbing capacity and sorptivity characteristics relative to reference concrete. Moreover, concrete made with coated aggregates exhibited better results in freeze-thaw and sulphate resistance tests.Öğe Polimer kaplı agrega ile üretilen hafif betonların durabilite özellikleri(Düzce Üniversitesi, 2023) Tuncer, Metin; Çomak, BekirBu çalışmada, tane boyutları 4 mm ile 16 mm arasında olan pomza agregaları yüksek yapışma ve yalıtım özellikleriyle bilinen polyester ile kaplanarak polyester kaplanmış pomza agregaları elde edilmiştir. Polyester kaplanmış ve kaplanmamış pomza agregaları iri agrega, doğal kırmataş kum ise ince agrega olarak kullanılarak 450 doz çimentolu 5 farklı seri hafif beton numuneleri üretilmiştir. Beton karışımlarında, polyester kaplanmış pomza ve kaplanmamış pomza agregaları hacimce %0, %25, %50, %75 ve %100 oranlarında yer değiştirilerek kullanılmıştır. Çalışmada, agrega deneyleri olarak özgül ağırlık ve su emme deneyleri gerçekleştirilmiştir. Taze betonlar üzerinde birim hacim ağırlık ve çökme deneyleri, sertleşmiş beton numuneleri üzerinde ise kuru birim hacim ağırlık, su emme, kılcal su emme, ultrases geçiş hızı, basınç dayanımı, sülfatlara dayanım, donma-çözülmeye karşı dayanım ve ısı iletim katsayılarını tayin edecek deneyler gerçekleştirilmiştir. Çalışmada, pomza agregalarının polyester kaplanmasıyla birlikte özgül ağırlıklarının arttığı, su emme oranlarının ise ortalama %85 oranda azaldığı belirlenmiştir. Basınç dayanımları ve ultrases geçiş hızları açısından en yüksek sonuçlar kaplanmamış pomza agregalarının kullanımı ile elde edilmiş ve polyester kaplanmış pomza agregaları ile üretilen beton numunelerinin basınç dayanımlarında düşüş gözlenmiştir. Polyester kaplanmış pomza ile üretilen betonların sülfatlara karşı daha iyi performans sergilediği tespit edilmiştir. Donma-çözülme performansları ve ısı iletim katsayıları açısından en olumlu sonuçlar polyester kaplanmış pomza agregalarının %25 oranında kullanımıyla elde edilen beton serisinde görülmüştür. Sonuç olarak, polyester kaplanmasıyla elde edilen agregaların hafif beton üretiminde kullanılabileceği belirlenmiştir.Öğe The use of natural (coconut) and artificial (glass) fibers in cement - polymer composites: An experimental study(Elsevier Sci Ltd, 2024) Demirdag, Caner; Nodehi, Mehrab; Bideci, Alper; Bideci, Ozlem Salli; Tuncer, Metin; Gencel, Osman; Ozbakkaloglu, TogayFiber reinforced concrete composites are a group of high-performance materials with considerably enhanced stress-strain properties. Similar effects can also be achieved using polymeric binders whereby the inclusion of the polymers as binder can significantly enhance the physical-mechanical properties of the resulting concretes. In this regard, the following study investigates the impact of utilizing natural (e.g., coconut) versus artificially manufactured fibers (e.g., glass fiber) in polymer-cementitious composites. In doing so, 14 mixes were produced using various ratios of the two fibers. To evaluate the properties of the produced samples a series of tests including flow diameters, unit weights, water absorption values, compressive strengths, flexural strengths and ultrasound transmission rates were determined. Also, to evaluate the microstructural cohesion of polymercement and polymer-coconut samples, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) has also been used. The results show that the surface texture of fibers can play a key role in major engineering properties of the fiber reinforced concretes and that the natural fibers have great potential to be used as high-performance materials in cementitious composites. Also, it is found that the use of polymer as the main binder can provide higher adhesion with fibers containing smoother surface (e.g., glass fiber) at the interfacial transition zone (ITZ). In the end, recommendation for future studies is also included.
