Browsing by Author "Aygun, Beyza Fahriye"

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Alternating Current Curing of Conductive Fly Ash-Slag Geopolymer Mortars: Performance, Characterization and Optimization
(Springernature, 2024) Aygun, Beyza Fahriye; Uysal, Mucteba; Bilir, Turhan; Cosgun, Turgay; Dilbas, Hasan
This research seeks to pinpoint the most robust series by subjecting geopolymer mortars (GMs) to electrical curing (AC) at 20 V based on different NaOH concentrations and GBFS/FA ratios. To enhance the electrical conductivity of GMs displaying optimal mechanical properties, carbon fiber (CF), steel fiber (SF), waste wire erosion (WWE) (0.25%, 0.50%, and 0.75%), and carbon black (CB) (1%, 2%, and 3%) were introduced into the chosen series. A comprehensive assessment encompassing compressive strength, flexural strength, ultrasonic pulse velocities, direct tensile strength and splitting tensile strengths were conducted on mixtures undergoing 24 h of AC. The study's findings indicated a substantial improvement in mechanical properties through electrical curing compared to ambient curing conditions. Notably, a correlation of up to 99% was established between direct and splitting tensile properties. The investigation revealed that the highest compressive strength, reaching 72.41 MPa at 1 day strength, was achieved through the thermal curing method with electric curing, particularly in the 100GBFS series. On the other hand, the optimum bending strength, approximately 19 MPa, was observed in the SFA075WWE series. These results highlight the efficacy of the thermal curing method with electric curing in enhancing the compressive strength of the 100GBFS series and the flexural strength of the SFA075WWE series, underscoring the potential benefits of specific curing methods for different series within the study.
An Investigation on Physical, Mechanical and Microstructural Properties of Electricity-Based Cured Gbfs-Fa Geopolymer
(Elsevier Sci Ltd, 2025) Aygun, Beyza Fahriye; Uysal, Mucteba; Bilir, Turhan; Cosgun, Turgay; Dilbas, Hasan
This paper aimed to investigate and develop curing process of geopolymer as a building material of the future. As well-known, the geopolymer may require heat while hardening and gaining strength. Application of heat treatment to the geopolymer on-site with heat sources are solutions, but it can be said that it is one of the most difficult processes of geopolymer. Thus, on-site electricity curing has been developed to overcome the difficulties in geopolymer curing. The developed curing process depended on application of AC voltage (10 V, 20 V, and 30 V) and the electrical resistance of geopolymer ensured a heat on geopolymer while curing process. In this experimental study, different NaOH and different GBFS/FA ratios were employed to seek the best solution. Also, the electrical resistance/conductivity of geopolymer was regulated with the addition of carbon fiber (CF), steel fiber (ST), waste wire erosion (WWE) (0.25 %, 0.50 %, and 0.75 %), and carbon black (CB) (1 %, 2 % and 3 %). Compressive strength (CS), flexural strength (FS), ultrasound pulse velocity (UPV), water absorption, void ratio, and unit weight were investigated parameters of geopolymer and were used to determine the best geopolymer mixtures. The internal and surface temperatures of geopolymer can be regulated by electricity-based thermal curing and it ensured a capability to set the optimum temperature on geopolymer. 20 V applications had the best efficiency in activating the geopolymerization reaction and the compressive strength positively affected, resulting the highest compressive strength as 78.02 MPa for SFA05WWE. Electricity-based thermal curing had a significant potential to surpass on-field-challenges in curing process of geopolymer and to obtain desired strength grade in not only indoor but also outdoor engineering applications.
Multi-Criteria Decision-Making Optimization-Based Fiber-Reinforced Waste Ceramic Powder-Based Geopolymer: Toward a Sustainable Net Zero/Low Co2 Emission Building Material
(Springernature, 2024) Kilic, Aysen Tahire; Uysal, Mucteba; Aygun, Beyza Fahriye; Nazir, Khizar; Canpolat, Orhan; Dilbas, Hasan
In this study, geopolymers (GMs) were produced using basalt fiber, polyamide fiber, and polypropylene fiber-reinforced and ground blast furnace slag (GBFS) waste ceramic powder (WCP). In the initial phase of the study, the optimal ingredient proportions were identified, and an ideal geopolymer was selected based on its highest compressive strength. Subsequently, at the second stage of the study, various fibers with differing proportions were incorporated into the ideal geopolymer, and the resulting properties were evaluated through laboratory testing. In the third stage, the optimal GMs were determined through a holistic approach, employing a multi-criteria decision-making method. A total of ten mixtures, comprising 23 properties (230 parameters in total), were subjected to a multi-criteria decision support method (TOPSIS). The optimal GM mixture with the proportions and suitable components was identified. The findings indicated that a 20% substitution of WCP with GBFS resulted in an optimal and cost-effective mixture in a 10 M NaOH solution, serving as a reference point or ideal unreinforced mixture in this research. With regard to the addition of fibers, all three types of fibers were observed to enhance the compressive, flexural, and splitting tensile strength of the WCP-GBFS-based GM. Maximum compressive strength was observed to be 60.15 MPa, while the flexural strength was 12.98 MPa and the splitting tensile strength was 3.45 MPa for the polyamide fiber (PA)-reinforced GM. Furthermore, all reinforced GMs exhibited enhanced abrasion resistance, with the inclusion of polypropylene fibers yielding the best results. Additionally, these fiber-reinforced GMs demonstrated significant resistance to high temperatures, even as temperatures increased. The TOPSIS results indicated that PA0.8 was the optimal GM, and its components with suitable components were recommended as a sustainable net zero/low CO2 emission building material.