Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Yilmaz, Ali Osman(3)
- Cavusoglu, Ibrahim(2)
- Yilmaz, Erol(2)
- Çavdar, Ahmet(2)
- Arslan, Metin(1)
- Aslı Bökü(1)
- Bingöl, Şinasi(1)
- Budak, Selahattin(1)
- Cullu, Mustafa(1)
- Durmuş, Gökhan(1)
- Ercikdi, Bayram(1)
- Kulekci, Gokhan(1)
- Külekci, Gökhan(1)
- Lermioğlu, Fatma(1)
- Seferoğlu, Mehmet Tevfik(1)
- Yakut, Yusuf(1)
- Yetgin, Şükrü(1)
- Yilmaz, Tekin(1)
- Yılmaz, Tekin(1)
- Çolak, Harun(1)
- Çullu, Mustafa(1)
Yayınlar
- MakaleAçık Erişim2025Scopus SJRQ4Long-term mechanical and physical behavior of rural concrete roads: A case study from Trabzon; [Kırsal beton yolların uzun vadeli mekanik ve fiziksel davranışı: Trabzon’dan bir vaka çalışması]
Seferoğlu, Mehmet Tevfik; Lermioğlu, Fatma
This study evaluates the long-term mechanical and physical performance of rural concrete pavements-defined as two-lane, unreinforced jointed plain concrete pavements constructed with a C25 mix design, an average slab thickness of 18–20 cm, serving low-to-moderate traffic volumes (<500 vehicles/day, <10% heavy vehicles), and built directly over compacted granular subgrade-using cylindrical core samples extracted from five neighborhoods in Trabzon, Türkiye: Çal, Gökçeler, Derecik, Çiğdemli, and Yolgören. Laboratory tests included compressive strength, splitting tensile strength, elastic modulus, capillary water absorption, and abrasion resistance. Yolgören exhibited the most severe deterioration, with a 34.84% loss in compressive strength, the lowest tensile strength, and the highest abrasion loss (0.088%), primarily attributed to poor drainage and heavy traffic. Derecik showed 22.18% strength loss and the lowest elastic modulus (14.9×103 MPa), likely due to weak subgrade and freeze-thaw cycles. Çal displayed moderate strength but had the highest capillarity coefficient and significant stiffness reduction (elastic modulus: 15.7×103 MPa), indicating high porosity and freeze-thaw damage. Çiğdemli performed best in surface durability, with the lowest abrasion loss (0.026%) and satisfactory elastic modulus. Gökçeler presented a rare case of strength gain (+0.85%) and retained acceptable stiffness, though minor surface wear (abrasion loss: 0.038%) was observed. These findings demonstrate that mix design alone does not guarantee long-term durability in rural pavements. Site-specific factors-such as curing effectiveness, drainage planning, subgrade preparation, and climate-must be considered in pavement design. A context-sensitive, performance-based approach is recommended for the sustainable development of rural road infrastructure.
- MakaleAçık Erişim2025Scopus SJRQ1Utilization of desiccant silica-gel wastes for the mechanical and microstructural performances of self-compacting mortars
Yılmaz, Tekin
The existing exploratory focuses to examine the effect of relocating ordinary Portland cement (OPC) by divergent proportions (2.5–15 %, by vol.) of desiccant silica-gel waste (DSGW) on the strength/durability/microstructural traits of self-compacting mortars (SCMs). A large experimental programme comprising unconfined compressive- (UCS: 7/28/56/90 days) and flexural-strength (FS: 7/28/56/90 days), freeze-thaw (F-T: 50/100 cycles), sorptivity (Sp: 28 days), porosity (PT: 28 days) and scanning electron microscope (SEM: 28 days) tests was conducted on the fabricated SCMs. From the gathered findings, the replacing OPC by 10 % DSGW, compared to the Control, was detected to signify the most efficacious contribution on SCMs' strength (UCS/FS = +15.2/12.3 %), durability (UCS/FS-losses after 50 and 100 F-T = −4.7/−6.1 % and − 10.0/−12.7 %) behavior, which is in tune with the ameliorated microstructure (Sp = −35.2 %, PT = −19.2 % and SEM = higher C-S-H gel, less micro-crack).
AtıfScopus4WoS4OpenAlex3
İncele - MakaleAçık Erişim2023Effect of aging time and temperature on properties of AA7075 alloy; [Yaşlandırma süresinin ve sıcaklığının AA7075 alaşımının özelliklerine etkisi]
Budak, Selahattin; Çolak, Harun; Yakut, Yusuf
In this study, the effect of aging at different temperatures and times on the properties of AA7075-T6 alloy was investigated. The samples prepared for the experimental studies were subjected to the solution, quenching, and then aging heat treatment at 100 °C and 200 °C for different periods (42-66-90 hours). The properties of the experimental samples were investigated by hardness, compression test, and scanning electron microscope (SEM). As a result of the studies, it was determined that the aging heat treatment had a positive effect on the microstructure and mechanical properties of the AA7075 alloy compared to the reference sample. Especially as a result of the heat treatments at 100 °C, higher results were obtained in hardness and compression strength compared to the initial values.
AtıfScopus1
İncele - MakaleYalnız künye2021Scopus SJRQ1Sodium silicate effect on setting properties, strength behavior and microstructure of cemented coal fly ash backfill
Cavusoglu, Ibrahim; Yilmaz, Erol; Yilmaz, Ali Osman
Representing an engineered mixture of coal fly ash, cement and water, cemented coal fly ash backfill (CCB) is typically employed for filling the openings created after coal excavation in the earth. A high rate of productivity for coal mines requires a high early-age strength backfill design. Therefore, the use of admixtures in CCB is key for accelerating the backfill setting time and augmenting short-and long-term strength. This study offers the effect of sodium silicate (SS) as an accelerator on early age mechanical and microstructure properties of CCB. SS-based admixture was used for a dosage of 0.5, 1 and 1.5 wt% in CCB that contains 25 wt% ordinary Portland cement OPC and 75 wt% coal fly ash. Backfill setting time was done by using the Vicat system while its strength and pore structure were measured by using the uniaxial compressive strength test, and scanning electron microscopy and Hg intrusion porosimetry. Results display that use of SS in CCB increases its short-term strength gain up to 14% and shortens the mining cycle by cutting its setting time up to 58%. The microstructure analyses also indicate that CCB formulated with SS has a finer pore structure than that without admixture. The outcomes of the present study will be advantageous to evaluate both setting time and strength behavior of CCB used in coal mines, thereby causing the effective backfill plan in terms of money saving and easy operation.
AtıfScopus149WoS141OpenAlex146İncele - MakaleYalnız künye2021Scopus SJRQ1Additivity effect on properties of cemented coal fly ash backfill containing water-reducing admixtures
Cavusoglu, Ibrahim; Yilmaz, Erol; Yilmaz, Ali Osman
Cemented coal fly ash backfill (CCB), a flowable structure of coal fly ash, binding agent and mixing water, has been often employed in mining operations to offer ground support as well as waste disposal solutions. An appropriate CCB mass should have sufficient rheological (e.g., workability) and mechanical (e.g., strength and stability) characteristics. Chemical admixtures are well known to greatly enhance the pumpability and strength properties of cementitious materials. Thus, this work provides the effect of water-reducing admixtures (namely, Sikament MR 50 W and Sikament FFN) on characteristics of CCB materials manufactured at a constant slump value. The role of admixtures in CCB mix is to reduce the cement-related costs, to modify the properties of the hardened backfills, and to ensure the quality of the backfill during mixing, transporting, placing, and curing. These admixtures were used at a dosage of 1% and 2% by weight of anhydrous material on cement. Several laboratory tests including slump, setting time, uniaxial compressive strength, scanning electron microscopy and mercury intrusion porosimetry were undertaken on CCB samples to understand their fresh and hardened performance. Experimental results show that the admixtures used ensure the slump required to deliver CCB at low water/cement ratios, improve short- and long-term backfill strengths up to 33%, and decrease the total porosity of the tested CCB. The findings of this study also show that the admixture use in CCB leads to a significant decrease in the considered cement content and a remarkable increase in the mechanical strength. As a result, understanding the actual fresh and hardened properties of CCB remains crucial for the choice of the greatest acting backfill admixture and for a fruitful change from capable experimental results to the in-situ conditions.
AtıfScopus76WoS69OpenAlex78İncele - MakaleYalnız künye2021Experimental Investigation of Usability of Construction Waste as Aggregate
Kulekci, Gokhan; Yilmaz, Ali Osman; Cullu, Mustafa
The aim of this work is to obtain recycled aggregate (RA) from construction debris in order to reduce the rapid consumption of aggregate resources and the environmental impact of these resources. In order to fulfill this aim, the density, porosity, Schmidt hardness test, uniaxial compression resistance, carbonation depth, and ultrasonic p-wave velocity experiments were conducted on different construction debris transported by trucks from 9 different points in Turkey. In addition, the debris samples taken were broken down to the size of the aggregate and subjected to the tests of density, porosity, moisture content, freeze-thaw, and impact resistance. As a result of the conducted experiments, the lowest mass loss as a result of freezing-thawing was in GRA with 9.36%, the highest mass loss was in ORA with 22.58%, the highest ORA average aggregate impact strength index was 21.27%, and the lowest TRA aggregate impact strength index was found to be 18.26%. İt was determined that most of the physical properties of RA obtained from the construction wreckage was within the limit values specified in the literature and that the recycled aggregates could be used instead of natural aggregate. With this work and these results, RA obtained could be used in many areas such as concrete aggregate in the construction sector, underground filling in mining, filling material in gunned concrete, and filling materials on highways.
AtıfScopus15WoS12OpenAlex8İncele - MakaleYalnız künye2018Scopus SJRQ2A New Nomogram Proposal to Determine Concrete Compressive Strength by Combined Nondestructive Testing Methods
Bingöl, Şinasi; Çavdar, Ahmet
Concrete is the most widely used construction material in contemporary construction technology. In particular, it holds an important place in the building industry in the world. Since concrete is a nonhomogeneous material, determining the strength of concrete accurately is quite difficult. In this respect, to check the mechanical properties of concrete in-situ, nondestructive test (NDT) methods can be used. They are useful as they do not damage concrete; however, these test results are sometimes deceptive. To reduce these deceptive results, destructive test methods were proposed to increase the accuracy of nondestructive methods. The objective of this study is to determine the strength of concrete with different characteristic strengths using destructive and NDT methods, and to establish new relationships between the compressive strength of concrete and Schmidt rebound values, and ultrasonic wave velocities. For this purpose, 101 concrete cube samples were prepared. After 7 and 28 days of curing, Schmidt rebound and ultrasonic wave velocity tests were applied as NDT methods. New formulations and graphs were established by carrying out a multiple regression analysis between the ultrasonic wave velocities, Schmidt rebound values, and compressive strengths. Thus, a new combined NDT method was developed with a nomogram. Furthermore, the applicability and accuracy of the formula and graph obtained were investigated by comparing the results of core samples from existing structures. The most important findings obtained from the study are summarized below. The concrete strength can be determined with nondestructive formulas obtained with an accuracy of 85%. High strength concrete cube samples are obtained in-house with 1.6% deviation, and core samples in-situ can be obtained with 7.3% deviation with the newly developed NDT nomogram. These test results show that the newly developed NDT formulas in this study are a very good alternative for determining concrete strength in-situ.
AtıfScopus13WoS9OpenAlex11İncele - MakaleYalnız künye2015Scopus SJRQ1Utilization of granulated marble wastes and waste bricks as mineral admixture in cemented paste backfill of sulphide-rich tailings
Ercikdi, Bayram; Külekci, Gökhan; Yilmaz, Tekin
This study presents the utilisation of granulated marble wastes (MW) as an additive (10-30 wt%) and waste bricks (WB) as replacement and additive (15-45 wt%) to ordinary Portland cement (OPC) for cemented paste backfill (CPB) of sulphide tailings. OPC was used as binder at 7 wt% dosage. Pozzolanic activity tests showed that the fineness of the WB samples, not the chemical composition, is the major factor affecting their pozzolanic activity. Although they do not exhibit any pozzolanic activity, the use of MW samples as an additive to OPC improves acid buffering capacity of CPB samples and enhances their short and long-term mechanical performance. The UCSs of CPB samples increased with increasing additive rates and decreased with increasing replacement ratios. All CPB samples produced the desired strength and durability when MW and WB were used as an additive to OPC. However, a binder dosage of >7 wt% was required to produce the desired 28-day strength of ≥0.7 MPa when the OPC was replaced by 15-45 wt% WB samples. The durability (i.e. no loss of strength) of CPB samples is closely inter-related with the calcination temperatures and glass phase content of WB.
AtıfScopus191WoS180OpenAlex195İncele - Yüksek Lisans TeziAçık Erişim2013Kırmataş agregalı betonların basınç ve yarmada çekme dayanımlarının sınırlı oranda dere kumu karıştırılmasıyla dengelenmesi
Aslı Bökü
Beton malzemesinin basınç dayanımı yüksek olup çekme dayanımı ise bunun yaklaşık 1/10'u kadardır. Beton üzerine gelen yüklemeden dolayı şekil değiştirme yapacaktır; betonun çekme kuvvetinin uygulandığı kısımda şekil değiştirme uzama olarak gerçekleşir. Çekme gerilmesi yapısal hesaplamalarda özellikle bazı yapıların projelendirme aşamasında ihmal edilmemelidir; çünkü çekme etkisinde ortaya çıkan çatlakların sınırlandırılması da yine çekme dayanımının yükseltilmesiyle mümkün olabilmektedir.Bu çalışmada dere kumu ve kırmataş karışımlarıyla hazırlanan farklı tane dağılımına sahip beton karışımlarının basınç ve çekmeye karşı gösterdikleri dayanımlarını karşılaştırmak için, uygulanan deneme karışımlarında değişken olarak agrega granülimetrisi ve ince malzeme olarak dere kumu kullanılmıştır. Hazırlanan beton bileşimlerinde % 22 - % 28 - %34 - % 40 - % 46 - % 48 - % 50 - % 52 - % 54 oranlarında dere kumu karışıma dahil edilmiştir. Tanık beton olarak tasarlanan 6. ve 11. deney bileşimlerinde ise kum olarak da kırma taş kullanılmıştır. 6. beton bileşiminde % 50 kırma taş, 11. beton bileşiminde % 25 kırma taş % 25 dere kumu kullanılmıştır. Dere kumunun karışım içersindeki yüzdesi değiştikçe, 4 ? 12,5; 12,5 ? 20 mm arasında kullanılan kırmataşın karışımdaki oranı da değişmiştir. Deney sonuçlarının dere kumu eklenmesi ile değiştiği görülmüştür. Çalışma sonunda, 28 günlük basınç dayanımı dere kumu oranına bağlı olarak önce bir düşüş sonra da artış göstermiştir. Dere kumu oranındaki artışa göre yarmada?çekme dayanımında parabolik bir ilişki ortaya çıkmıştır. Böylece basınç ile yarmada?çekme dayanımı arasında ise matematiksel bir bağıntı kurulmaya çalışılmıştır.Çalışmada kırmataş agrega içerisinde yuvarlak ve kaygan dere kumu karıştırılmasıyla gerek basınç dayanımında, gerek çekme dayanımında, burada yarmada çekme dayanımında artış kaydedildiği görülmüştür. Böylece kırmataş sayesinde çekme bölgesinde oluşacak çatlaklar engellenmiş ya da sınırlanmış olurken dere kumuyla sağlanan, yerine yerleştirme kolaylığı sayesinde de betonun artan yoğunluğuna bağlı olarak basınç dayanımında da yükselme kaydedilmiştir.Anahtar Kelimeler: Basınç dayanımı, Dere kumu, Gerilme?şekil değiştirme,Kırmataş,Yarmada çekme dayanımı,
- MakaleYalnız künye2011Scopus SJRQ4The effect of antifreeze admixtures on compressive strength of concretes subjected to frost action
Arslan, Metin; Çullu, Mustafa; Durmuş, Gökhan
This study aims to determine the effect of antifreeze admixture used in the concretes subjected to frost action on the concrete compressive strength. Three groups of concrete samples of C30 class were prepared with antifreeze admixtures by using the mixture of 30% calcium nitrate and 5% hydroxy ethoxy amin (A), calcium nitrate (B), Polyhydroxy amine (C). Concrete samples are put in the freezer in a fresh state 15 min after the mixing. Samples are subjected to frost action in 0, -5, -10, -15 and -20°C degrees for 48 hours. On the concrete samples water cured after 48 hours, compressive strength tests of 28 day are conducted. Consequently, it is seen that with the increase of the set temperature that concrete is cured, compressive strength of concrete is decreased and among all types of antifreezes the maximum decrease is seen between 0 and -5°C while the decrease in compressive strength is relatively less for -10, -15 and -20°C.
AtıfScopus6WoS7İncele - MakaleYalnız künye2007Scopus SJRQ1Availability of tuffs from northeast of Turkey as natural pozzolan on cement, some chemical and mechanical relationships
Çavdar, Ahmet; Yetgin, Şükrü
At Northeast of Turkey, it is possible to find plenty of volcanic origin rocks and rich natural pozzolan beds. In this study, the pozzolanic activities of six types of different tuff samples taken from Trabzon and Bayburt regions (Northeast of Turkey) were examined according to the related standard and it was determined that the compressive strengths were varying between 6.7-11.0 MPa. In addition, the chemical compositions of these samples, except one, were consistent with the related standard. On the other hand, the results obtained from these studies were that increase in the proportion of SiO2 in the pozzolan increases the pozzolanic activity.
AtıfScopus74OpenAlex73İncele