SDG 9 · Sanayi, Yenilikçilik ve Altyapı · SDG · Erzincan Binali Yıldırım Üniversitesi

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ArticleYalnız künye2025/r/ebyu/11835
Integrated multi-manned disassembly line balancing problem with reverse supply chain design strategies by considering lot sizing
Öksüz, Elif; Yılmaz, Ömer Faruk; Öksüz, Mehmet Kürşat; Gürsoy Yılmaz, Beren
Due to strict governmental regulations, manufacturers have increasingly focused on recovering end-of-life (EoL) products through disassembly lines, aiming to achieve economic benefits while addressing the environmental aspects of supply chain sustainability. Disassembly line balancing (DLB) has become a key challenge for enterprises seeking to perform environmentally conscious manufacturing as part of a closed-loop supply chain policy. Therefore, designing a sustainable closed-loop supply chain requires analyzing interrelated problems by focusing on strategic-, tactical-, and operational-level decisions simultaneously. This study introduces an integrated problem that addresses multi-manned DLB, lot sizing, and reverse supply chain (RSC) design problems. To mathematically represent the problem, a generic optimization model is developed to minimize overall costs, including station opening, inventory holding, shortage, transportation, and collection center/facility opening costs. This study addresses several research questions to explore the impact of distribution strategies (centralized and decentralized) on multi-manned DLB and lot size decisions within the context of reverse supply chain design.
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ArticleAçık Erişim2025/r/ebyu/11804
Optimizing Bitumen Performance in Warm Mix Asphalt Using Cecabase RT BIO10: A Taguchi-Based Experimental Approach
Çakı, Mustafa; Baş, Fatih İrfan
Flexible pavements stand out as the most commonly used worldwide, compared to rigid and composite pavements, owing to their versatility and widespread application. The use of hot mix asphalt (HMA) in flexible pavements causes significant environmental concerns due to high CO2 emissions and energy consumption, whereas warm mix asphalt (WMA) technologies have gained popularity in recent decades, offering a more sustainable alternative by enabling asphalt production at lower temperatures. WMA technologies can be categorized into three main groups: foaming, organic additives, and chemical additives, with each offering distinct benefits for performance and environmental impact. One of the chemical additives used in WMA production is Cecabase RT BIO10. In this study, virgin bitumen with 50/70 penetration was modified by adding Cecabase RT BIO10 at four levels: 0%, 0.3%, 0.4%, and 0.5% by weight. The experimental design employed a Taguchi L16 orthogonal array to systematically evaluate the effects of various factors on modified bitumen performance. Binders were prepared at four temperatures (110 °C, 120 °C, 130 °C, and 140 °C), four mixing durations (15, 20, 25, and 30 min), and four mixing speeds (1000, 2000, 3000, and 4000 rpm), enabling an efficient analysis of each parameter’s impact. The prepared binders were subjected to a series of tests, including penetration, softening point, flash point, rotational thin film oven test (RTFOT), elastic recovery, Marshall stability, ultrasonic pulse velocity (UPV), and FTIR analysis. These tests were conducted to investigate the effects of various parameters and levels on the binder properties. Additionally, stiffness and seismic modules were evaluated to provide a more comprehensive understanding of the binder’s performance. The experiment results revealed that the penetration, elastic recovery percentage, and Marshall stability increased with increasing additive content while the softening point and RTFOT mass loss decreased. At a high service temperature of 40 °C, the stiffness modulus of the modified bitumen decreased slightly. At a low service temperature of −10 °C, it decreased further. Additionally, the incorporation of Cecabase RT BIO10 led to an increase in the seismic modulus. Through optimization using the Taguchi method, the optimal levels were determined to be a 0.4% Cecabase RT BIO10 ratio, 140 °C mixing temperature, 30 min mixing time, and 1000 RPM mixing speed. The optimal responses for each test were identified and integrated into a unified optimal response, resulting in a comprehensive design guide with 95% confidence level estimates for all possible level combinations.
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ArticleYalnız künye2025/r/ebyu/11797
Building resilient supply chains: unveiling the interplay of reflexivity, supply chain innovation and improvisation capability
Polater, Abdüssamet
Purpose – Drawing on the dynamic capabilities view (DCV), this study aims to examine the mediating role of supply chain innovation (SCI) in the relationship between reflexivity and supply chain resilience (SCR), as well as the moderating role of improvisation capability (IMPR). Design/methodology/approach – In this study, survey data were collected from 245 mid- and senior-level managers in Türkiye's top 1, 000 industrial firms using a structured questionnaire. Data were analyzed using SPSS, Amos and PROCESS macro. Analytical procedures included confirmatory factor analysis (CFA), evaluation of construct validity and reliability, as well as correlation, mediation and moderated mediation analyses. Findings – Our results reveal that reflexivity has a significant and positive relationship with SCR and that SCI partially mediates this relationship. Additionally, moderated mediation analysis reveals that IMPR not only moderates the relationship between SCI and SCR but also reinforces the indirect effect of reflexivity on SCR through SCI. Practical implications – Managers can strengthen SCR by embedding reflexivity, fostering innovation through SCI and enhancing IMPR. Developing these interrelated capabilities enables proactive adaptation, accelerates crisis response and sustains competitive advantage in volatile and disruption-prone environments. Originality/value – This study advances the current frontier of SCR research by integrating reflexivity, SCI and IMPR into a unified capability-based model. It offers academics a cognitive-process perspective (i.e., reflexivity) missing from current SCR literature, guides managers in operationalizing reflective learning into adaptive strategies and informs policymakers seeking systemic resilience in disruption-prone economies.
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ArticleYalnız künye2025/r/ebyu/11744
Traffic Impact Analysis of a Regional Shopping Center Using Microsimulation with the Analytical Hierarchy Process (AHP) Approach
Bayata, Halim Ferit; Baş, Fatih İrfan; Mengi, Gamze Şeyda
In today’s modern city life, shopping centers have become a part of the urban identity. Erzincanpark Shopping Center, which was put into service at the city’s western entrance in 2022 in Erzincan, created an additional traffic volume causing inadequacies and accidents in urban transportation. This study aimed to identify these problems and inadequacies and develop possible solutions and suggestions. To examine the importance of coordination between junctions, traffic flow, and phase arrangements, Erzincanpark was chosen as the study area, and the junctions on Halitpasa Street were examined. The study used the traffic impact analysis method to examine traffic counts at junctions, signal optimization, travel time, queue length, delay, CO2, NOx, VOC emissions, and fuel consumption values. The study results showed that Yildiz and Nedim Muratoglu junctions should be modern roundabouts to ensure the optimum situation. Furthermore, it was determined that there was no change in the parameters studied in the design of Ergan Junction in 3 different ways: signaled, 4-way (without an island), and modern roundabout. Analytical Hierarchy Process (AHP), one of the multi-criteria decision- approaches, was used to find the feasible result, considering safety and construction costs.
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ArticleYalnız künye2025/r/ebyu/11609
An experimental evaluation on structural performance level of corroded reinforced concrete frames
Turan, Ahmet İhsan; Ayaz, Yaşar; Yalciner, Hakan; Kumbasaroglu, Atila
A total of 5 full-scale Reinforced Concrete (RC) frames were tested to develop new models for predicting the structural behavior of corroded RC frames and to verify the accuracy of the models mostly developed for RC columns. Four corroded and one non-corroded RC frame were tested under cyclic loading. Corroded RC frames were tested under displacement-controlled cyclic loading at four corrosion levels and for a constant applied axial load ratio of 0.20, with the same concrete compression strength level and reinforcement bar layout. Actual corrosion ratios were obtained following the loading tests, breaking all RC columns and beams and extracting all reinforcement bars from concrete. The test results demonstrated that the corrosion level played an active role in the structural capacity of the RC frames. Initial corrosion crack widths had more significant effects on structural performance. Some models proposed for corroded RC columns can also be used for corroded RC frames in terms of yield and ultimate load capacities according to the corrosion levels of the columns and beam composing the RC frame. It was also concluded from the test results that the displacement-based ductility ratio for corroded RC frames could still be misleading if they were not computed according to energy-based or bilateral failure criteria. Structural properties such as initial/secant stiffness and energy absorption capacity calculated based on experimental measurements for RC frames had further disclosed corrosion effects.
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ArticleAçık Erişim2025/r/ebyu/11535
Predictive Modeling of Urban Travel Demand Using Neural Networks and Regression Analysis
Çolak, Muhammed Ali; Bayrak, Osman Ünsal
Urban transportation systems are increasingly strained by population growth, changing mobility patterns, and the need for sustainable infrastructure planning. The accurate modeling of urban trip generation is critical for effective and sustainable transportation planning, especially in the context of rapidly growing urban populations and evolving travel behaviors. This study investigated the application of advanced statistical methods and artificial intelligence-based techniques for forecasting urban travel demand. Erzincan, with a population of approximately 200,000, serves as a representative mid-sized city, offering valuable insights for transportation planning and traffic management. Data collected from various user groups, including households and university students, provide a comprehensive understanding of local travel behavior. Four predictive modeling techniques, linear regression, Poisson regression, negative binomial regression, and artificial neural networks (ANNs), were applied to the dataset, followed by a comparative performance evaluation. Additionally, a macro-level simulation was conducted using VISUM (Release 18.2.22) software to evaluate the current transportation network and assess the potential impacts of proposed improvement scenarios. The results show that the ANN model provided the highest predictive accuracy for household-based data (R2 = 0.62), while the linear regression model yielded the best results for dormitory-based data (R2 = 0.95). Furthermore, Poisson regression proved most effective in estimating the minimum trip generation time, which was estimated to be 22.77 min under simulated conditions. The study offers practical insights for transport planners and policymakers by demonstrating how predictive analytics and simulation tools can be integrated to address urban mobility challenges.
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ArticleYalnız künye2025/r/ebyu/11533
Deep learning and adaptive boosting for hydroelectric power prediction using hydro-meteorological data: Insights and feature importance analysis
Karakoyun, Yakup; Katipoğlu, Okan Mert; Dogan, Ahmet
This study explores the use of modern artificial intelligence (AI) models such as Adaptive Boosting (AdaBoost), Autoencoder Based Regression Model (Autoencoder), Deep Neural Network (DNN), Echo State Network (ESN), Light Gradient Boosting Machine (LGBM) Residual Neural Network (ResNet) and feature importance techniques to predict energy production. Daily rainfall, streamflow, temperature and energy production data between 2016 and 2019 were used in the study. According to the feature importance analysis performed using the LGBM model, streamflow, temperature, and precipitation were identified as the most critical parameters influencing energy production. This structured AI-driven approach provided robust model evaluation and reliable performance measurements. As revealed by the analysis, the LGBM model showed the most accurate result with the values of root mean square error (RMSE: 98.27), mean absolute error (MAE: 73.93), Akaike information criterion (AIC: 17,100), Nash–Sutcliffe efficiency coefficient (NSE: 0.69), Kling–Gupta efficiency (KGE: 0.77), coefficient of determination (R2: 0.69), mean bias error (MBE: −5.23), bias factor (BF: 1.02), and percent bias (PBIAS: 1.51), while the DNN model came in with the second-best results. These findings emphasize both the effectiveness of deep learning and ensemble AI models and their practical application in improving hydroelectric power generation forecasting. Furthermore, the study underscores the importance of accurately monitoring and managing streamflow for the optimization of hydroelectric systems.
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ArticleAçık Erişim2025/r/ebyu/11518
Efficient Soft-Switching Snubber Cell Design for PWM DC-DC Boost Converters: Enhanced Load-Independent Performance
Sahin, Yakup; Ting, Naim Suleyman
Soft-switching (SS) boost converters are extensively utilized in applications such as renewable energy systems, electric vehicles, and high-efficiency power supplies, as they offer reduced switching losses and enhanced overall efficiency. Zero-voltage transition (ZVT) snubber cells that used SS operation perform poorly in zero-voltage switching (ZVS) turn-off at light load, although they perform well at heavy load. This study proposes a novel SS snubber cell for the PWM-DC boost converter, ensuring excellent ZVS turn-off performance under all load conditions. The main switch is turned off with ZVS at heavy and light load, so the turn-off performance is independent of the load conditions. In addition, the main switch is switched on with ZVT, and the main diode is switched with SS. The main and auxiliary semiconductor components do not expose additional voltage. In addition, the semiconductor switches are switched on with zero-current switching (ZCS) and switched off with ZVS, whereas the auxiliary diode is switched with SS. The theoretical analysis of the converter is presented, and an experimental study is conducted to demonstrate the analysis. The proposed converter is operated with an output power of 500 W and a switching frequency of 100 kHz.
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ArticleYalnız künye2025/r/ebyu/11420
Assessing the influence of green innovation and environmental policy stringency on CO2 emissions in BRICS
Çetinkaya, Ozlem Akguc; Çatik, Abdurrahman Nazif; Balli, Esra; Manga, Muge; Destek, Mehmet Akif
This article examines the effect of environmental policy stringency and green innovation on CO2 emissions in the BRICS nations, using annual data from 1990 to 2019 utilizing panel FMOLS and DOLS estimators and Method of Moments Quantile Regression (MMQR). To this end, we estimate an equation in which CO2 emissions are explained by GDP, trade openness, nonrenewable and renewable energy consumption, the environmental stringency index, and green innovation, as measured by the number of patent applications for environmentally related inventions. FMOLS and DOLS results reveal that GDP, nonrenewable energy consumption, and trade openness have a positive effect on environmental pollution, whereas improvements in renewable energy consumption and environmental regulations lead to a drop in CO2 emissions. However, green innovation does not have a significant effect on CO2 emissions. MMQR estimates demonstrate that the GDP has a positive effect on CO2 emissions across all quantiles, suggesting that a higher degree of economic growth is associated with higher emissions. Based on findings, empirical evidence suggests that BRICS countries should follow the policies encouraging the reduction of nonrenewable energy consumption in the region without harming the development of the economy. Besides, policymakers should promote renewable energy consumption and enhance investment in green innovation to achieve sustainable development and environmental quality.
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ArticleYalnız künye2025/r/ebyu/11363
Appropriate Intersection Design Type Based on TOPSIS Multiple Criteria Decision Method with AIMSUN Mesoscopic Simulation
Bayata, Halim Ferit; Baş, Fatih İrfan; Demircioğlu, Muhammed Sami; Çolak, Muhammed Ali
The increasing world population has also increased the demand for vehicles and brought along various problems such as traffic delays, accidents, and air pollution. In addition, the increase in the number of vehicles causes an increase in the time spent at intersections, negatively affecting people’s quality of life, distracting drivers, and unsafe driving practices. Moreover, greenhouse gas emissions, including CO2 and NOx from vehicles, cause climate change and deterioration of air quality. To solve these problems, in this study, seven signalized intersections on a corridor in the city center of Erzincan province were examined. Using the Aimsun traffic simulation program, factors such as CO2, VOC, NOx emissions, queue length, delay time, travel time, and speed were evaluated. Using one of the multiple criteria decision methods, the TOPSIS method, the ideal scenario was determined based on the simulation results, considering the construction costs. The study revealed significant improvements in several parameters. CO2 emissions were reduced by 10%, delay time by 35%, VOC emissions by 14%, NOx emissions by 13%, queue length by 35%, delay by 38%, and travel by 19%. Furthermore, the speed was increased by 15%.
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ArticleAçık Erişim2025/r/ebyu/11359
The Assessment of Corrosion-Damaged Reinforced Concrete Structures: A Case Study from Erzincan, Türkiye
Turan, Ahmet İhsan
Reinforced concrete (RC) structures constructed in accordance with earthquake regulations and design principles are subjected to numerous effects, including wind, dead, live, snow, rain, seismic loads, and environmental effects on their service life. One of the most common problems caused by environmental effects is corrosion that occurs in the reinforced concrete reinforcement bar. Concrete can protect the reinforcement bar with sufficient strength and durability properties and undamaged cross-section integrity from corrosion under normal conditions. However, poor concrete quality, high permeability, insufficient concrete cover thickness, and workmanship defects can lead to corrosion of the reinforcement bars. Corrosion in the reinforcement bars can weaken the mechanical properties of the material and shorten the service life of the structure. In this study, the deterioration of concrete and reinforcement in a reinforced concrete structure built in 1982 in Erzincan was investigated using both destructive and non-destructive methods. The aim of examining these materials together was to evaluate the parameters affecting corrosion mechanisms at the material level as well. The results were interpreted by evaluating the climatic data (precipitation, humidity, wind, and temperature) and air quality at the structure's location. Qualitative and quantitative analyses revealed that the increasing corrosion rate causes deterioration in the mechanical properties of the reinforcement bars and that this deterioration is closely related to the type of corrosion. Additionally, it was concluded that the temperature differences and air pollution in Erzincan caused structural deterioration in reinforced concrete elements and accelerated corrosion of the reinforcement bars.
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ArticleAçık Erişim2025/r/ebyu/11345
Investigation of the Impact of Intersection Designs, Signalization, and Directions of Intersection Arms on Microscopic Networks: The Case of Erzurum Province
Zirek, Zühal; Çolak, Muhammed Ali
Transportation has an important connection in many aspects such as economic growth, trade, tourism and social interaction. Today, the demand for transportation services is increasing with the rapid socio-economic development. This increase brings with it various traffic problems. Effective intersection design in preventing congestion, delays and accidents is of great importance in terms of ensuring traffic safety and sustainability. In this study, Gürcükapı Intersection and Taşhan Intersection were remodeled with Aimsun software in order to reduce the density at the intersections in Erzurum province and to meet traffic needs. Signalization was added to the modeled intersections, the directions of the intersection arms were changed and four alternative scenarios were created with these changes using current scenario. A total of five scenarios, including the current scenario and the developed alternatives, were evaluated and compared based on travel time, delay time, waiting time, speed, queuing, instant CO2, NOx, PM (Particulate Matter) and VOC (Volatile Organic Compounds) values. As a result of the comparison, the scenario in which the current intersection arm direction and Gürcükapı and Taşhan intersections are modernized and there is no signaling system was determined as the most effective scenario.
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ArticleYalnız künye2025/r/ebyu/11258
Enhanced soft-switched T-type neutral-point clamped (T-NPC) inverter with reduced component number
Ozgenel, Mehmet Cihat; Ting, Naim Suleyman; Sahin, Yakup
This paper presents an enhanced soft-switched T-type neutral-point clamped inverter featuring a compact active snubber cell that delivers zero-voltage transition turn-on and zero-voltage switching (ZVS) turn-off for the main switches, while auxiliary switches operate with zero-current switching turn-on and ZVS turn-off. Unlike prior designs, four auxiliary-path diodes are eliminated, reducing component count, conduction path length, and reverse-recovery losses, which in turn lowers cost, eases thermal management, and boosts power density. The proposed topology maintains full soft switching (SS) for all active devices without introducing additional voltage or current stress. The theoretical analysis of the inverter is clarified, and the operating modes for steady-state analysis are presented in detail. Experimental validation on a 400 V, 1 kW, and 100 kHz prototype demonstrates consistent SS across load conditions and a peak efficiency of 97.2%. The combination of higher efficiency, structural simplicity, and cost-effectiveness makes the proposed inverter a strong candidate for high-performance, compact T-type applications in renewable energy, and electric drive systems.
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ArticleYalnız künye2025/r/ebyu/11218
Fracture behavior of warm mix asphalt mixtures incorporating Cecabase and recycled concrete aggregate: An experimental and numerical assessment
Çolak, Muhammed Ali; Keleş, Ömer Faruk; Baş, Fatih İrfan; Demi̇ri̇z, Ahmet Oğuz
This study investigates the fracture performance of warm mix asphalt (WMA) mixtures modified with Cecabase RT BIO10 and various recycled concrete aggregate (RCA) proportions using laboratory tests and finite element modeling. Semi-Circular Bending (SCB) tests at –15 °C under Mode I loading were performed to measure fracture toughness (KIC), fracture energy (GF, pre-peak and post-peak), stiffness, and flexibility indices. Unlike many prior studies relying on a single approach, fracture toughness was calculated through all major analytical methods and validated with ANSYS finite element simulations. Results showed that increasing Cecabase content notably improved fracture resistance, while higher RCA levels reduced mechanical properties due to the porous nature of RCA. Fracture energy analysis indicated that post-peak deformation parameters correlated more strongly with GF than stiffness indices, highlighting the importance of ductility in asphalt performance. Correlation analyses revealed tensile strength (TS) and tensile stiffness index (TSI) largely evolve independently from post-peak flexibility indicators such as flexibility index (FI), toughness index (TI), and crack resistance index (CRI). Among mixtures tested, the combination of 0.50 % Cecabase and 10 % RCA exhibited the most balanced performance with high TSI, TS, and GF values. These findings emphasize the need to optimize both additive and RCA content to enhance WMA mixtures’ mechanical integrity and sustainability. The proposed approach offers a practical and environmentally friendly framework for designing durable asphalt mixtures suited to low-temperature pavements.
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ArticleYalnız künye2025/r/ebyu/11174
A new approach for lightweight polymer concrete production: Determination of the influence of resin and perlite types on the mechanical performance of polymer concrete
Ciminli, Ahmet Taha; Bulut, H. Alperen
The interest in perlite is increasing significantly in the construction sector in terms of both energy and material in the construction of efficient buildings. This interest arises from the growing demand for environmentally friendly building materials that can mitigate the environmental impact of high cement production. In order for polymer concretes, which have many advantages over traditional concrete, to help reduce damages under earthquake loads and reduce costs, lightweight polymer concrete production should be done using lightweight aggregates. In this study, a new approach for lightweight polymer concrete production was presented for the first time, and the aim was to determine the effect of the compatibility of natural perlite and expanded perlite aggregates with polyester and vinylester resins on the mechanical performance of polymer concrete. For this purpose, natural and expanded perlites were used as fine aggregate in polymer concretes instead of quartz aggregate at the ratios of 0 %, 5 %, and 10 %. As binder materials, unsaturated polyester resin and vinylester resin were selected. Fresh density, compressive, flexural, and splitting tensile strengths, ultrasonic pulse velocity (UPV), modulus of elasticity, and toughness tests were performed on polymer concretes after 7, 28, and 90 days. Furthermore, scanning electron microscope (SEM) analyses were performed to investigate the changes in the microstructure of the polymer concretes. The compressive, flexural, and splitting tensile strength results of polyester resin polymer concretes produced with 5 % natural perlite aggregate were higher than the control concrete. Very high correlations were found between the strength results of polymer concretes and UPV values for all days. Modulus of elasticity and toughness values of vinylester resin polymer concretes with natural perlite aggregate were higher than those of polyester resin polymer concretes. SEM analysis results and experimental results were consistent with each other. Considering all the experimental results, it was revealed that the ideal perlite type and ratio is 5 % natural perlite aggregate. Unlike the literature, and in a unique way, lightweight polymer concretes with high mechanical performance polyester/vinylester resin, especially with natural perlite aggregate, could be produced with a much lower resin ratio (15 %). Thanks to perlite, more sustainable, environmentally friendly, and energy-efficient lightweight polymer concretes can be produced, offering alternative solutions to traditional construction materials.
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ArticleAçık Erişim2025/r/ebyu/11124
Enhancing the performance of bituminous hot mix pavements with graphene nanoplatelet additive using taguchi optimization
Işık, Suna; Baş, Fatih İrfan
Flexible pavement, where bitumen serves as the binding material, is the most widely used type of pavement due to its many advantages. Hot mix asphalt (HMA) pavements are often selected for their ability to create safe, comfortable, cost-effective, and sustainable roadways. However, HMA pavements deteriorate due to traffic, climatic conditions, and environmental influences. To improve their resistance to these challenges, bitumen is modified with various additives. This study utilized graphene nanoplatelet (GNP) to modify bitumen due to its strength, flexibility, and cost-effectiveness. Based on the experimental plan established by the Taguchi method, 16 different mixtures were prepared using four parameters, each with four levels: GNP rates of 0 %, 0.35 %, 0.70 %, and 1 %; mixing temperatures of 145°C, 160°C, 175°C, and 190°C; mixing times of 15, 30, 45, and 60 min; and mixing speeds of 1000, 2000, 3000, and 4000 rpm. A comprehensive set of tests, including penetration, softening point, flash point, elastic recovery, rotational thin film oven test (RTFOT), Fourier transform infrared spectroscopy (FTIR), and Marshall design experiments, were conducted on the mixtures to evaluate the influence of the selected parameters and levels on the properties of bitumen. The bitumen's temperature susceptibility and stiffness modulus were analyzed, providing insights into its behavior under varying temperature conditions. The results of the study indicated that the GNP additive led to a reduction in the RTFOT mass loss and softening point of pure bitumen, while increasing the penetration, flash point, elastic recovery, and Marshall stability. The multiple response performance index (MRPI) optimizations identified the optimal levels as a GNP rate of 0.70 %, a mixing temperature of 145°C, a mixing time of 15 min, and a mixing speed of 2000 rpm. GNP contributed to reduced energy consumption and ecological advantages by lowering the optimal mixing temperature to 145°C. It reduced the plastic deformation at high temperatures and improved low-temperature cracking behavior by decreasing the temperature sensitivity of bitumen.
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ArticleYalnız künye2025/r/ebyu/11123
Eco-Friendly Stabilization of Coarse-Grained Soil Using Gum Rosin and Natural Fiber
Akoğuz, Harun
Cement and its derivatives are frequently used as traditional construction materials for soil improvement. However, the most commonly used ordinary Portland cement can significantly affect the ecological environment. This study proposes an innovative alternative improvement method to stabilize soil by incorporating gum rosin (GR), a natural polymer, into the soil. For this purpose, the improvement of soil with different grain diameters (G1 and G2) by incorporating different proportions of sisal fiber (0.2%, 0.4%, 0.6%, and 0.8%) into different proportions of GR (5%, 10%, and 15%) was investigated. The focus of the study was the treatment of GR natural polymer to the soils by heating as an innovative method and to determine the characteristic changes in the strength and permeability of the soil. Firstly, the setting time of this method was determined. After that, unconfined compressive strength (UCS), ultrasonic pulse velocity (UPV), and permeability tests were performed on the samples subjected to different curing times (1, 7, and 28 days). According to the results obtained from the experiments, it was determined that the setting time of the samples reached a stable state after one day of curing. The average strengths of G1 and G2 soils were 3.72 MPa and 2.48 MPa, respectively, and it was observed that the decrease in grain diameter contributed positively to the increase in strength. In addition, it was determined that both the strength and the failure stress increased with the inclusion of fiber. Moreover, a high coefficient of R2 = 0.9428 was obtained from the variation of the UPV test and UCS test, and the usability of the UPV test results in estimating the strength was evaluated. According to the permeability test results, a negligible decrease in permeability was observed after the treatment, and in this case, it was evaluated that this method could be used in many different engineering fields, such as permeable asphalt pavements. The findings suggest that this natural polymer may have potential in certain engineering applications, though its wider use requires further exploration.
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ArticleAçık Erişim2025/r/ebyu/11088
Experimental study on compressive strength of clay soil stabilized with construction and demolition waste-based geopolymer
Isik, Adem
This study investigated soil stabilization on clay soil using construction and demolition waste (CDW) as a geopolymer binder. The mechanical performance of stabilized soil was investigated under various CDW-based geopolymer amounts, curing times, and alkali activator concentrations. Unconfined compressive strength (UCS) testing was conducted to determine the shear strength of soil samples. The UCS capacities of soil samples were approximately 8.1, 12.2, and 14.6 times higher than the unstabilized soil sample for 7, 28, and 91 days of curing. Moreover, it is observed that increasing the molarity of alkali activators, especially NaOH, enhanced the UCS capacity of geopolymer-stabilized soil. However, using Na2SiO3 in combination with NaOH had a negative impact on UCS capacity. Because the water in the Na2SiO3 content increased the water content of the soil sample and caused it to have a softer consistency, this was also observed with the increase in activator solution to binder (s/b) ratios. SEM–EDX and XRD tests were performed to investigate the microstructure of stabilized samples. These tests showed that there was agreement with the UCS test results. Finally, a Multiple Linear Regression (MLR) and Artificial Neural Network (ANN) analysis were performed to estimate UCS capacity of geopolymer-stabilized soils.
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ArticleAçık Erişim2025/r/ebyu/11083
Experimental Investigation of Metamaterial-Inspired Periodic Foundation Systems with Embedded Piezoelectric Layers for Seismic Vibration Attenuation †
Oz, Mehmet Furkan; Kumbasaroglu, Atila; Yalciner, Hakan; Korozlu, Nurettin; Babacan, Yunus; Çatır, Fulya Esra Cimilli; Sayarcan, Done
Seismic metamaterial-inspired periodic foundations have emerged as promising vibration-mitigation concepts capable of attenuating seismic wave propagation within specific frequency bands. This study presents an experimental investigation on the dynamic response of periodic foundation configurations, with and without embedded piezoelectric layers, to evaluate their vibration-attenuation characteristics. The experimental program employed a shake table driven by a 0.75 kW servo motor and included excitation step counts of 3000, 4000, and 5000. Accelerometers mounted on the specimen surfaces recorded vibration data at 80 ms intervals. Three foundation configurations were tested: (i) a conventional reinforced concrete block, (ii) a one-dimensional periodic foundation composed of alternating concrete and rubber layers, and (iii) a periodic foundation incorporating piezoelectric modules. Time-domain and frequency-domain analyses showed that the periodic foundations achieved notable reductions in both peak and RMS accelerations, especially near resonance frequencies. The configuration, including piezoelectric layers, exhibited similar attenuation performance while also generating measurable instantaneous voltage outputs under vibration. However, these voltage peaks—reaching a maximum of 1.64 V—represent only a laboratory-scale, proof-of-concept demonstration of electromechanical coupling rather than a practical or continuous form of energy harvesting, given the inherently sporadic nature of seismic excitation. Overall, the results confirm that the tested system is not a full metamaterial in the classical sense but rather a metamaterial-inspired periodic arrangement capable of inducing band-gap-based vibration attenuation. The inclusion of piezoelectric elements provides auxiliary sensing and micro-energy-generation capabilities, offering a preliminary foundation for future multifunctional seismic-protection concepts.
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ArticleAçık Erişim2025/r/ebyu/11077
Performance evaluation of waste glass in soil improvement: Influence of particle size of waste glass on mechanical, microstructural, and durability characteristics
Akoğuz, Harun
The accumulation of waste glass (WG) from construction and demolition waste is detrimental to the environment due to its imperishable nature; therefore, it is crucial to investigate a sustainable way to recycle and reuse the WG. To address this issue, this study examined the mechanical strength, microstructural characteristics, and environmental durability—specifically under wet-dry (WD) and freeze-thaw (FT) cycles—of WG obtained from construction and demolition waste, with a focus on its suitability as a binding material for soil improvement applications. Firstly, sand and WG were mixed, and an alkali solution was injected into the mixture, considering various parameters, including WG particle size, mixing proportions, sodium hydroxide (NaOH) concentration, and curing time. Subsequently, the effect of WG grain sizes on micromorphology characteristics and mineralogical phases was evaluated before and after the treatment through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and ultrasonic pulse velocity (UPV). The results revealed that reducing the WG particle size and increasing the WG/S ratio significantly improved the strength of the WG-treated samples. Additionally, decreasing the NaOH concentration and extending the curing time also positively influenced their strength. The UCS test results indicate that the particle size of WG significantly influenced the strength development of the samples, as the maximum compressive strength increased from 1.42 MPa to 7.82 MPa with the decrease in particle size. Although the maximum UCS values of the samples varied with different WG particle sizes, the values exceed the minimum criterion of 0.80 MPa required for use as a road substructure, as specified in the ASTM D4609 standard. Moreover, as WG grain size decreased, more geopolymer gels formed, continuing to fill the voids and making the overall structure denser, and the changes during geopolymerization were confirmed by XRD, SEM, FTIR, and UPV analysis. The optimum WG/S ratio was found to be 20 %, with strength increasing by approximately 3.88 times higher as the WG/S ratio shifted from 5 % to 20 %. In addition, the optimum NaOH concentration was determined to be 10 M, as higher molarities led to a decrease in strength. Moreover, UPV results indicate that WG-treated sand soils exhibited UPV values 9.4–13 times greater than untreated soils. The WD and FT test results indicate that WG-treated samples experienced more rapid disintegration in the WD cycle than in the FT cycle; however, a decrease in WG particle size resulted in reduced disintegration effects in both WD and FT conditions. In both the FT and WD cycles, the declining trend exhibited a stable tendency around the eighth cycle. Nevertheless, the WD cycling damage considerably intensified disintegration, causing a profound deterioration in the structural integrity of the samples. As a result, repeated WD cycles lead to the formation of microcracks, which progressively weaken soil aggregation and reduce the overall strength of the samples. Consequently, this green and simple soil improvement technique can provide more inspiration for reducing waste and building material costs through efficient use of construction and demolition waste.
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