Sürdürülebilir Kalkınma Amaçları
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- MakaleAçık Erişim2026Scopus SJRQ2Sustainable self-compacting mortars: mechanical, durability and microstructural evaluation with cement replacement materials under aggressive environmental conditions
Karabulut, Büşra; Yön, Merve Şahin; Karataş, Mehmet
The aim of this study is to assess the mechanical, physical and durability properties of environmentally friendly self-compacting mortars produced using materials containing industrial waste and natural stone. The test series were produced by substituting diatomite (D) and C class fly ash (F) with Portland cement (PC) up to 30% by weight. To evaluate the workability, mechanical and durability properties of self-compacting mortars (SCM), a total of 19 series, one of which was a reference sample, were prepared. The samples, whose mechanical properties and durability properties were investigated under sulphate attack and freeze-thaw effects, were prepared as 40 × 40 × 160 mm, and the series, whose physical properties were examined, were prepared as 50 × 50 × 50 mm. Also, SEM/EDS (Scanning Electron Microscope - Energy Dispersive X-Ray) and XRD (X-Ray Diffraction) analyses were carried out to evaluate the microstructural properties of the mixtures. When the 90-day compressive strength results were examined, it was determined that the highest decrease in compressive strength compared to the control sample occurred in the D20F10 sample with a rate of 61%, and the least decrease occurred in the D5 series with a rate of 10%. When the losses in compressive strength were evaluated after 50 freeze-thaw cycles, it was determined that there was a 100% reduction in the binary and ternary series containing D15 and D20. After six months of sulphate exposure, the D5F25 sample exhibited the most significant compressive strength reduction at roughly 40%, whereas the D15F15 series experienced the least compressive strength decline at around 5%.
- MakaleAçık Erişim2026Scopus SJRQ1Enhancing the mechanical and durability properties of fly ash/GGBS-based geopolymer mortars using dunite and polypropylene fibers
Cemalgil, Selim; Gülmez, Nihan; Yön, Merve Şahin; Karataş, Mehmet
Polypropylene (PP) fiber-reinforced geopolymer mortar reduces the high brittleness of conventional geopolymer made with natural aggregates. However, the effects of different precursor materials on the performance of PP fiber-reinforced self-compacting geopolymer mortar (SCGM) remain unclear. This study investigates the feasibility of using dunite (D), a magnesium-rich ultramafic rock with consistent mineralogy and low processing energy demand that enhances thermal stability and durability, as an alternative precursor for fly ash (FA)/ground granulated blast furnace slag (GGBS)-based geopolymers. The study examined the workability, flexural and compressive strengths, and sorptivity of mortars cured at 20 ± 2°C and 60 ± 5% relative humidity, as well as their durability under freeze–thaw cycles and high-temperature exposure. Interfacial interactions between aggregates and the geopolymer matrix, along with microstructural and morphological changes caused by fire, were analyzed using scanning electron microscopy (SEM). X-ray diffraction (XRD) and thermogravimetric analysis (TGA) were also performed for detailed material characterization. The mix containing 30% dunite exhibited the highest flexural strength, reaching 5.70 MPa at 28 days, the highest among all mixes. Under fire exposure, the mix containing 10% dunite significantly reduced mechanical strength loss and retained about 33.3% higher residual flexural strength than the FA–slag control mix at 600°C.
AtıfScopus1WoS1OpenAlex1
İncele - MakaleYalnız künye2026Scopus SJRQ1High-temperature, freeze–thaw, and sulfate resistance of mortars incorporating ternary blends of fly ash, chromite, and waste glass
Gülmez, Nihan; Kanellopoulos, Antonios
The demand for sustainable construction materials promotes the use of industrial waste in cement-based systems. This study examines mortars incorporating fly ash (FA) (0%, 7.5%, and 15%), waste glass, and chromite aggregates for mechanical and durability performance. Specimens underwent compressive strength, freeze–thaw, high-temperature, sulfate attack, and ultrasonic pulse velocity tests, while microstructure was characterized by x-ray diffraction, thermogravimetric analysis, and scanning electron microscopy–energy-dispersive spectroscopy. Mortars with 7.5% FA exhibited relatively high compressive strength and improved freeze–thaw resistance. The combined use of chromite and FA improved strength retention at 800°C, reaching 23 MPa with 7.5% FA and 50% chromite. The greatest sulfate resistance occurred in mortars containing 15% FA and 15% waste glass, maintaining compressive strengths of 61 and 70.9 MPa after MgSO4 and Na2SO4 exposure, respectively.
- MakaleAçık Erişim2024Scopus SJRQ2The Behavior of Ceramic Fiber Geopolymer Concrete under the Effect of High Temperature
Dalğıç, Aras; Yılmazer Polat, Berivan
Geopolymer concrete (GC), also known as green concrete, contains slag, silica fume, and fly ash as binders. The absence of cement in concrete is critical to protect the world from the environmental impacts of cement production. In addition, exposure to high temperatures is a critical parameter that causes loss of strength in concrete. In this study, Geopolymer concrete samples were prepared with 10 different samples containing different proportions of slag, silica fume, and porous ash and subjected to various physical, mechanical, and optical tests. The sample (GS90) with optimum workability and compressive strength, which also showed high performance in water absorption, freeze-thaw, and UPV tests, was used in high-temperature tests. Portland cement concrete (PCC) was used as a control sample. This study investigated the effect of high temperatures on the physical and mechanical properties of fiber-free GCs containing 2%, 5%, and 10% by volume of ceramic fibers. Therefore, fiber-reinforced, fiber-free, and PCC specimens were subjected to high-temperature tests at 100, 300, 600, and 900 °C. As a result of the observation of crack growth, color changes, and compressive strength parameters in the samples subjected to high-temperature tests, the thermal resistance of the 10% ceramic fiber geopolymer concrete sample was 2.5% higher than other samples. There is no study in the literature that examines the behavior of ceramic fiber-reinforced geopolymer concrete at high temperatures. This research revealed an important finding by proving that ceramic fiber reinforcement increases the compressive strength of geopolymer concretes at a remarkable rate after high-temperature impact.
AtıfScopus8WoS10OpenAlex8İncele - Yüksek Lisans TeziAçık Erişim2023Puzolan ve atık lastik agregası içeren çelik lifli betonların mekanik özellikleri
Tacettin Şahin
Bu çalışmada, Puzolan ve atık lastik agregası kullanımının çelik lifli beton özelliklerine etkisi araştırılmıştır. Bu amaçla C30 sınıfında, farklı çelik lif ve atık lastik oranlarına sahip numuneler imal edilmiştir. CEM I 42,5 R sınıfı portland çimentosunun kullanıldığı karışımda, puzolan olarak uçucu kül kullanılmıştır. Uçucu kül, karışımdaki çimento ağırlığının % 15'i (67,5 kg/m³) oranında ikameli olarak kullanılmıştır. Su/çimento oranı kontrol numunesi karışımında 0,48, akışkanlaştırıcı kullanılan lifli numune karışımlarında ise 0,40 olacak şekilde ayarlanmıştır. Bu amaçla % 1,5 oranında süper akışkanlaştırıcı kullanılmıştır. Karışımda, 35 mm uzunlukta 0,75 mm çapında galvanize, tutkallı çelik lifler 50 kg/m³ ve 30 kg/m³ oranlarında kullanılmıştır. 0-5 mm, 5-12 mm ve 12-22 mm çapında doğal agregalar sırasıyla % 45, % 30 ve % 25 oranlarında kullanılmıştır. Taze beton karışımları % 10 ve % 15 oranlarında öğütülmüş atık lastik, ince agrega yerine ikameli edilerek hazırlanmıştır. Hazırlanan karışımlar taze beton deneyleri yapıldıktan sonra kalıplara yerleştirildi. 24 saat sonra kalıptan alınan beton numuneler 28 gün laboratuarda kür tanklarında, daha sonra açıkta bekletilmiştir. Üretilen numuneler; basınç, eğilmede çekme, yarmada çekme, diyagonal yarma, ultrases geçiş hızı, kılcal su emme, donma çözülme ve aşınma deneylerine tabi tutulmuştur. Bu testler için 30 adet 100x100x500 mm boyutlarında kiriş, 135 adet 100x100x100 mm boyutlarında küp numuneler üretilmiştir. Deneyler sonucunda çelik lifli betonların neredeyse tamamının lif içermeyen kontrol numunesine kıyasla daha yüksek dayanıma sahip olduğu anlaşılmıştır. Ayrıca çelik lifli betonlar kendi aralarında kıyaslandıklarında; % 10 atık lastik ve 50 kg çelik lif içeren K1 ile % 10 oranında atık lastik ve 30 kg çelik lif içeren K3 beton numunelerinin diğer betonlara göre daha yüksek dayanıma sahip olduğu anlaşılmıştır. 150 ve 300 devir donma çözülme etkisine maruz bırakılan tüm lifli numuneler kontrol numunesinden yaklaşık % 50 oranında daha az etkilenmiştir. Kendi aralarında kıyaslandıklarında 50 kg lif ve % 10 öğütülmüş atık lastik içeren beton numunelerin 300 devir donma çözülme etkisine karşı daha dayanıklı olduğu anlaşılmıştır. Tüm deney sonuçları topluca değerlendirildiğinde, 50 kg/m³ çelik lif ve % 10 oranında atık lastik agregası içeren K1 betonunun en ideal oranlara sahip karışım olduğu tespit edilmiştir.