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Sürdürülebilir Kalkınma Amaçları

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• MakaleYalnız künye2026/r/gumushane/13524
  Mechanical properties of polypropylene fiber-reinforced shotcrete based chromite flotation waste using a nondestructive testing method

  Aksüt, Yavuz Selim; Seferoğlu, Mehmet Tevfik

  This study examines the mechanical behavior and non-destructive assessment of shotcrete reinforced with polypropylene fibers (PPFs) and incorporating chromite flotation waste (CFW) as a partial substitute for fine aggregate. Shotcrete mixtures were prepared with four CFW replacement levels (0–30%) and four PPFs volume fractions (0–1%) and their compressive strength, splitting tensile strength and static modulus of elasticity were evaluated. Poisson's ratio and ultrasonic pulse velocity (UPV) were experimentally determined. The effect of fiber reinforcement and waste incorporation on the mechanical behavior was evaluated through statistical correlation, simple regression and multivariable predictive modeling approaches. The results showed that moderate PPFs contents (0.25–0.5%) generally enhanced compressive and tensile performance while excessive fiber dosage (1%) led to strength and stiffness reductions due to increased heterogeneity, fiber agglomeration and void formation at high CFW replacement levels. Increasing CFW content resulted in systematic reductions in UPV values with an average decrease of approximately 3–4% per 10% CFW replacement indicating changes in matrix continuity and internal structure. However, these UPV reductions were not directly proportional to losses in mechanical strength or elastic stiffness. Correlation analyses revealed weak to moderate relationships between UPV and mechanical properties confirming that UPV alone is insufficient to represent the complex behavior of fiber-reinforced, waste-based shotcrete systems. Simple UPV-based regression models exhibited limited predictive capability for both compressive strength (R2 ~ 0.16) and static modulus of elasticity (R2 ~ 0.002). In contrast, multivariable regression models incorporating normalized UPV, CFW replacement ratio and PPFs volume fraction together with their interaction terms, significantly improved prediction accuracy. The proposed models achieved high coefficients of determination (R2 ~ 0.86 for compressive strength and R2 ~ 0.97 for static elastic modulus) with substantially reduced root mean square error (RMSE) values. Finally, the findings demonstrate that UPV can be effectively used as a non-destructive indicator for estimating the strength and stiffness of PPFs reinforced shotcrete incorporating CFW only when material specific parameters are explicitly considered.

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• MakaleAçık Erişim2025/r/gumushane/19507
  Plentmiks Temel Tabakası Yapımında Krom Pasa Malzemesi Kullanımı ve Ekonomik Analizi

  Seferoglu, Mehmet Tevfik; Acı, Elif Nur

  Bu araştırmanın amacı, Karayolu Teknik Şartnamesi (KTŞ) standartlarına uygun tasarlanacak olan bir plentmiks temel (PMT) tabakası için Kop Dağı (Bayburt) krom maden sahasında cevher üretim faaliyetleri sonucu ortaya çıkan ve ekonomik değeri bulunmayan atıl durumdaki krom (Cr) pasa malzemesinin belirli oranlarda kullanımının sağlayacağı mali faydaların belirlenmesidir. Pasa karışım oranlarının maliyet analizleri yapılarak bir karayolunun PMT tabakası yapım maliyetleri de dahil olmak üzere krom pasasının temin noktasına olan mesafeye bağlı ekonomiklik değerlendirmesi yapılmıştır. Çalışma neticesinde %100 Cr içerikli karışımının PMT tip-1 tabakalarında kullanımının mümkün olduğu ve %100 doğal agrega (Da) ile tasarlanan tabakaya kıyasla en uzak mesafe için bile %18’in üzerinde mali kazanç sağladığı belirlenmiştir. Cr pasa malzemelerinin, PMT tip-1 tabakaları için Da yerine alternatif olabileceği ve çevresel faydaların yanısıra tatmin edici ölçüde ekonomik fayda da sağlayacağı sonucuna varılmıştır.

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• MakaleAçık Erişim2025/r/gumushane/14064
  Long-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.

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• MakaleYayıncıda açık erişim2025/r/gumushane/12550
  Chrome waste utilization in base layers: Mechanical strength and environmental risk assessment

  Seferoğlu, Mehmet Tevfik; Acı, Elif Nur

  This study investigates the partial substitution of natural aggregate (Na) with chrome mine waste (Crw) in highway base layers, focusing on mechanical performance and environmental safety. Crw-Na mixtures with contents from 0 % to 100 % were tested using CBR, cyclic plate loading, chemical, and leachate tests. The 15 % Crw-85 % Na mixture achieved the highest CBR (287.4 %) with limited deformation (37 mm). Although the 60 % Crw blend also met the required strength level (156.6 %), it showed higher settlement (50 mm) and three times greater vertical strain. SEM-EDX and chemical results indicated increased magnesium content and mineral changes at higher Crw ratios. Leachate tests confirmed compliance with TS266 and international water standards; all samples were categorized as neutral drainage with low metal risk. The findings show that Crw improves strength without causing environmental risk. Among tested mixtures, 15 % Crw offered the most balanced outcome in terms of field stability and performance.

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• MakaleAçık Erişim2025/r/gumushane/12431
  Flexural Behavior and Sustainability of Dual-Waste Fiber-Reinforced Concrete Designed for Pavement Applications

  Seferoğlu, Mehmet Tevfik; Aksüt, Yavuz Selim; Seferoğlu, Ayşegül Güneş

  This study evaluates the mechanical performance and sustainability potential of fiber-reinforced concrete incorporating mine tailings as the fine aggregate and waste tire wire as the reinforcing fiber. The concrete mixtures contained 0.2%, 0.4%, and 0.6% waste tire wire with the natural fine aggregate replaced entirely with Pb-Zn-Cu tailings. The mixtures were tested for porosity, water absorption, compressive strength, splitting tensile strength, flexural strength, toughness, fracture energy, and ductility to assess their mechanical performance and durability. The mine tailings improved the microstructure and reduced water absorption, particularly with tire wire. Using waste tire wire improved the compressive, tensile, and flexural performance; in particular, W-6 showed a 18.2% rise in compressive strength and a more than twofold increase in flexural strength relative to the control mix. The flexural toughness and fracture energy rose by up to 161%, while the ductility peaked at a fiber content of 0.2%. These gains were attributed to fiber crack-bridging and post-cracking energy absorption. The dual-waste system also reduced porosity, improved durability, and demonstrated strong potential for rigid pavement applications such as highways, industrial yards, and airport runways that require high fatigue resistance and a long service life. Beyond technical performance, this approach offers a sustainable solution that lowers maintenance, reduces life-cycle costs, and aligns with circular economy principles.

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• MakaleYayıncıda açık erişim2025/r/gumushane/12336
  Assessing the reliability of the lightweight deflectometer test for compaction control in highway subbase layers through SPSS analysis

  Seferoğlu, Mehmet Tevfik; Seferoğlu, Ayşegül Güneş; Akpınar, Muhammet Vefa; Iribagiza, Divine

  The condition of the highway base/subbase layers is critical for the durability and performance of the road pavement. Compaction control plays an important role in determining the ability of these layers to support traffic loads, their strength and stability. Various methods are used to evaluate the compaction rate of subbase layers; such as nuclear density gauge (NDG) and sand cone. These methods also have their own limitations and difficulties. While the NDG test is used to determine the compaction percentages, the lightweight deflectometer (LWD) test is used as a relatively more practical, portable and non-destructive method to measure the surface stiffness modulus (Emod). In this study, the possibility of using the surface stiffness modulus obtained by the LWD test in the subbase layer instead of each other is investigated by establishing a correlation between the compaction percentages determined by the NDG test. To investigate how well the LWD results are in line with established methods, only correlation and regression analysis of SPSS software are focused on. Correlation analysis helped us assess the strength and direction of the relationships between LWD modulus values and compaction percentages, while regression analysis provided insights into the predictive capability of LWD in estimating compaction outcomes. These methods helped evaluate the reliability and accuracy of LWD as a compaction control tool, providing a deeper understanding of the role of LWD in highway subbase layer assessment.

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• MakaleAçık Erişim2023/r/gumushane/11995
  Investigation of the structural damage caused by blasting activities in tunnels to surrounding buildings: The case of Gümüşhane belt highway; [Tünellerde patlatma faaliyetlerinin çevre binalara verdiği yapısal hasarın incelenmesi: Gümüşhane çevre yolu örneği]

  Seferoğlu, Mehmet Tevfik; Seferoğlu, Ayşegül Güneş; Akaryali, Enver

  Tunnels are road transport structures that reduce traffic and expropriation problems, noise, and possible damage to animals and plants, and provide safer, more comfortable, and faster transportation for vehicles compared to highways. However, some environmental problems occur during tunnel construction. These problems such as vibration, noise, rock throwing, etc. caused by the blasting process used during tunnel excavation on buildings and people should be well investigated. In this study, two buildings located close to the exit and entrance of two tunnels (T2 and T3 tunnels) on the Gümüşhane belt road were chosen to investigate. Firstly, the existing damages in the first building, which is 7 m away from the T2 tunnel exit, and the second building, which is 60 m away from the T3 tunnel entrance, were analyzed by considering criteria such as the geological and ground condition of the land and the building materials used during the construction of those building. In addition, the negative effects on the buildings were evaluated by calculating the vibrations after the blasting process in the tunnel with the help of various empirical formulas. Investigation on site showed that building 1 was built of masonry and building 2 was built of reinforced concrete, and that deep cracks had formed in the bearing systems of both buildings, spills occurred in the walls, and fractures in the windows. Also, calculations with empirical formulas showed that the vibration rates caused by blasting process in the 1st and 2nd buildings were as 385.68 mm/sec and 6.91 mm/sec, respectively, and these vibration values were above the standard values. The data obtained through examination on-site and empirical approaches show that it would be dangerous for people to be resident in both buildings.

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• MakaleYalnız künye2022/r/gumushane/15891
  Investigating the Influence of Joint Reinforcements of Portland Cement Concrete Slabs Under Asphalt Concrete Overlays on Vertical Deflections Using Accelerated Pavement Testing

  Seferoglu, Mehmet Tevfik; Seferoglu, Aysegul Gunes; Çelik, Muhammet; Akpinar, Muhammet Vefa

  Joint gaps between slabs in underlying Portland cement concrete (PCC) pavements are critical factors in the life span of asphalt concrete (AC) overlays. Therefore, being informed about the vertical deflections that may occur around the joints is important. In this study the joints were reinforced with three different materials: ethylene propylene diene monomer (i.e., rubber joint filler [RJF] reinforcement), bitumen-based sealant (i.e., rubber plate [RP] reinforcement), and steel plate (SP) (i.e., SP reinforcement), to limit the vertical movement of the underlying PCC. Tests were conducted at the accelerated pavement testing facility for two different AC overlay thicknesses, 50 mm and 100 mm, during 100,000 passages to investigate the influence of AC overlay thickness variations on slab vertical deflections and to also evaluate types of joint reinforcement on slab vertical deflections. For 50-mm thick AC overlay, the most effective joint reinforcements to prevent deformations caused by loading were RP, RJF, and SP; for a 100-mm thickness, this was determined to be RJF, SP, and RP, respectively.

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• MakaleAçık Erişim2021/r/gumushane/14630
  Performance of AC overlays using geogrids on PCC contraction joints

  Çelik, Muhammet; Seferoğlu, Mehmet Tevfik; Akpınar, Muhammet Vefa

  It is widely known that vertical displacements and strains occur on the joints and these cause defects on the asphalt concrete (AC) overlays on existing Portland cement concrete (PCC) pavements. Various approaches were introduced to minimize these defects. In this study, the effect of joint support formed using the geogrid material with grout mortar on the vertical displacement of PCC and the strain at the bottom of the AC layer. Produced layers were exposed to 1,186,000 Equivalent Single Axle Load (ESAL) in an APT (Accelerated Pavement Test) facility and the results were monitored. According to the obtained results, the use of AC overlay reduces vertical displacement in the PCC by 75%. When geogrid reinforced AC overlay was used, an additional reduction in displacement by 41.2% was achieved. Geogrid reinforcement reduced strain values formed at the bottom of the AC layer from 29.5% to 92.5%. The use of geogrid at joints instead of increasing the thickness of the AC layer from 50 to 80 mm resulted a more significant reduction in both strain and displacement. Besides, the usage of a geogrid interlayer instead of increasing the thickness of the AC layer also provided a significant cost reduction of 57.9% in overall cost.

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• MakaleAçık Erişim2021/r/gumushane/14573
  Evaluation of Load-Transfer Efficiency of Steel Mesh Reinforced Contraction Joints in Concrete Pavement: Accelerated Pavement Test and FE Analysis

  Celik, Muhammet; Seferoglu, Mehmet Tevfik; Akpinar, Muhammet Vefa; Nasery, Mohammad Manzoor; Seferoglu, Aysegul Gunes

  Transverse contraction joints are by far the most common type of joint in jointed plain concrete pavements. Early loading of contraction joints can create a weakened vertical plane and later grow as a full-depth crack. In this study, load transfer efficiency (LTE) of steel mesh reinforced transverse contraction joints were studied at accelerated pavement tests (APT). 3D finite element (FE) model of jointed plain concrete pavement (JPCP) was developed to study deflections and crack propagation in just under the joint of the concrete pavement. The APT tests were focused on the LTE values before and after the crack initiation under the contraction joint region. Experiments were performed on three slabs in which two of these slabs were prepared without reinforcement and one of them was reinforced with steel mesh. Data generated by APT was used for verification of crack propagation modeling in the finite element analysis. Steel mesh reinforced slab gave the lowest vertical deflections (51μm) and highest LTE (91.56%). The LTE value in the reinforced slab after 25,000 passes was 13.63% higher than the average of unreinforced slabs. The findings suggest that the load transfer efficiency was found to be a complex parameter and should be interpreted together with average displacement values when contraction joints are evaluated at early traffic loadings.

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