Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleYalnız künye2026Mechanical 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.
- MakaleAçık Erişim2025Long-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.
- MakaleYayıncıda açık erişim2025Chrome 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.
- MakaleAçık Erişim2025Flexural 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.
- MakaleYayıncıda açık erişim2025Assessing 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.
- MakaleAçık Erişim2023Investigation 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.
- MakaleAçık Erişim2021Performance 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.
- MakaleAçık Erişim2020Beton Yol Uygulamalarında Derz Türlerine Göre Düşey Deplasman Oluşumlarının İncelenmesi ve Maliyet Analizi: Trabzon-Rize Örneği
Akpinar, Muhammet Vefa; Seferoğlu, Mehmet Tevfik; Güneş Seferoğlu, Ayşegül; Çelik, Muhammet
Türkiye'de beton yolların kullanımı her geçen gün artmaktadır. Özellikle Doğu Karadeniz Bölgesi'nde 10.000 km'nin üzerinde beton yol bulunmaktadır. Bu çalışmada, Trabzon ve Rize İllerinde yapılan beton yol uygulamaları incelenerek yaygın olarak kullanılan kaplama kalınlığı ve beton basınç dayanımı belirlenmiştir. Karadeniz Teknik Üniversitesi Hızlandırılmış Yol Tesisinde örnek kaplama modeli hazırlanmış ve gerçek trafik yüklemeleri altında beton kaplamaların düşey deplasman değişimleri incelenmiştir. Farklı derz türleri (hasır donatılı yarım derz, donatısız yarım derz, dolgulu tam derz ve dolgusuz tam derz) kullanılarak fayda ve maliyet analizi yapılmıştır. Elde edilen verilere göre, derzlerin yarım derz olması ve kaplamada donatı kullanılması, donatısız yarım derzlere göre 1.3 kat, dolgulu tam derze göre yaklaşık 4 kat, dolgusuz tam derzlere göre ise yaklaşık 9 kat daha az düşey deplasman oluşmasını sağlamaktadır. Ayrıca yapılan maliyet analizlerine göre kaplamalarda hasır donatının bulunması, beton kaplama maliyetine km’de 38.002,76 TL (%11,6) fiyat farkı oluşturmaktadır. Bu bilgiler ışığında, beton kaplamalarda yarım derz yapılmasının ve hasır donatının kullanılmasının kaplama derz bölgelerindeki faydasına oranla maliyetinin oldukça düşük olduğu sonucuna ulaşılmıştır. Ayrıca mevcut tam derzli beton yollarda %7'lik ilave bir maliyet ile derzlerin içinin bitüm esaslı dolgu malzemesi ve kauçuk levhalarla kaplanmasının, düşey deplasman değerlerini en az yarı yarıya azaltılabileceği ve bu sayede kaplama ömrünün uzatılabileceği tespit edilmiştir.
- MakaleYayıncıda açık erişim2019Investigating the mechanical behavior of reclaimed asphalt pavement (RAP) bases in large scale test box
Seferoğlu, Ayşegül Güneş; Seferoğlu, Mehmet Tevfik; Akpinar, Muhammet Vefa
The objective of this research was to assess the elastic deformations and permanent strains of reclaimed asphalt pavement (RAP) material as a base layer when it is treated or untreated with pozzolanic cement under cyclic loads. A large-scale cyclic plate loading testing (CPLT) device was developed for studying the mechanical characteristics of pavement base layer. The laboratory test results indicated that when the RAP percentage of the mixtures increased, elastic deformations and permanent strains increased, but the opposite was true when the cement percentage increased. It was concluded that 100% RAP material can be used in base layers with 3% pozzolanic cement. The obtained deformation values and strain rates can be used as reasonable default design input values by pavement designers when using RAP as a substitute for natural aggregate base layers.
- MakaleYalnız künye2018Experimental study on cement-treated and untreated RAP blended bases: Cyclic plate loading test
Seferoğlu, Ayşegül Güneş; Seferoğlu, Mehmet Tevfik; Akpinar, Muhammet Vefa
The asphalt surrounding the reclaimed asphalt pavement (RAP) aggregates decrease the performance characteristics of road layers. RAP material increases the permanent deformation potential of road layers under the traffic load. In this study, the performances of RAP-VA (Virgin aggregate) mixtures was tested using cyclic plate loading test by adding pozzolanic cement into mixtures in order to use RAP material at the rate of 100% and to minimize the permanent deformation in plant-mix base courses (PBC). The permanent surface deformations of base course were measured at different points throughout 100 loading cycles and all of the measurements were compared to that of base course prepared from 100% VA. The effect of RAP/cement rate of mixtures on the permanent deformations was examined and it was determined that the increase in RAP rate increased the permanent deformations but cement significantly decreased it. Moreover, considering the material costs of mixtures, the cost analysis was performed and the profit margins that using RAP and cement offers to constructors were computed.