Browsing by Author "Mydin, Md Azree Othuman"

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Citation - WoS: 13
Citation - Scopus: 15
Effect of Gbfs Ratio and Recycled Steel Tire Wire on the Mechanical and Microstructural Properties of Geopolymer Concrete Under Ambient and Oven Curing Conditions
(Elsevier, 2024) Celik, Ali Ihsan; Karalar, Memduh; Aksoylu, Ceyhun; Mydin, Md Azree Othuman; Althaqafi, Essam; Yilmaz, Fatih; Umiye, Osman Ahmed
In this study, the effects of waste steel wire ratios, granulated blast furnace slag (GBFS) ratios, and different curing methods on geopolymer concrete (GPC) were investigated. For this purpose, 12 mixtures were produced and eight of them were cured under ambient conditions and the remaining four were cured in an oven. Steel wire ratios and GBFS ratios were added to GPC as 0-1-2-3 % and 0-10-20 % by volume and weight, respectively. As a result of the mixtures, cubes, cylinders, and beams were obtained and these elements were subjected to compression, tensile, and flexural tests. As a result of the tests, the compressive strengths of the specimens were obtained as 8.5%, 19.7%, and 24.9% for ambient curing and 10.4%, 23.2%, and 32.2% for oven curing, respectively, as the steel wire fiber increased from 0 % to 3 %. The maximum compressive strength of the oven-cured specimen with 3% steel wire fiber was measured as 42.56 MPa. The tensile strength of GPC also increased as the steel wire increased. The highest tensile strength was obtained with 3 % steel wire. In addition, oven curing conditions increased the tensile strength more than ambient curing. The flexural strength (FS) increased by 21.3 %, 29.4%, and 33.8 % with increasing steel wire ratios of 1 %, 2 %, and 3 %, respectively. The FS was further increased by oven curing conditions and the maximum FS was achieved with 3 % steel wire. In ambient curing conditions, a successful geopolymerization was achieved due to the high calcium content in the samples containing 20 % GBFS. This allowed to obtain similar strengths between ambient curing and oven curing. Although the oven curing values were higher, similar results were obtained for the samples cured in an ambient containing 20 % GBFS. As a result of the study, mixtures containing 3 % steel wire and 20% GBFS provided sufficient strength without oven curing and increased the usability of GPC under ambient conditions.
Citation - WoS: 3
Citation - Scopus: 3
Shear and Flexural Performance of Reinforced Geopolymer Concrete Beams Cured Under Ambient and Oven Conditions With Environmentally Friendly Waste Steel Tire Wire Additives
(Nature Portfolio, 2025) Ozkilic, Yasin Onuralp; Celik, Ali Ihsan; Aksoylu, Ceyhun; Karalar, Memduh; Mydin, Md Azree Othuman; Althaqafi, Essam; Umiye, Osman Ahmed
In this study, the effects of Granulated Blast Furnace Slag (GBFS) and Waste Steel Wire (WSW) admixtures on the flexural and shear performances of Reinforced Geopolymer Concrete Beams cured under oven and ambient conditions were investigated experimentally and analytically in detail. The research used 100 mm and 270 mm stirrup spacings and changed GBFS and WSW with 0%, 10%, 20%, and 1%, 2%, and 3%, respectively. To evaluate flexural and shear strength of reinforced GPC, 100 x 150 x 1000 mm samples were made. The results showed how material proportions affect flexural, and shear beam mechanical performance and ductility. In flexural beams, increasing the GBFS ratio to 10% enhanced load bearing capability and preserved ductility. However, 20% of GBFS reduced load bearing capability and brittle fractures. It was found that mixtures with GBFS of 10% and WSW of 3% are optimum for flexural beams. For shear beams, brittle fracture was observed for all GBFS and WSW ratios and ductile behavior was not achieved. Increasing GBFS content to 10% boosted capacity from 2.05 to 19.37%, however increasing it to 20% dropped capacity from 2.72 to 15.10%. Increasing WSW content enhanced load bearing capability, however increasing GBFS content over 10% did not. It is emphasized that different materials and design methods should be investigated to ensure ductile behavior in shear beams. Increasing the WSW ratio from 0 to 3% boosted energy consumption capacity by 2.78 times. But raising the GBFS ratio to 20% reduced energy consumption capacity by 66%. In addition, AS3600 predicted beam damage more correctly in different conventional computations. This study shows that the GBFS ratio should be limited to 10% and the WSW ratio to 3%. This combination maintains ductility in flexural beams and gives a safe design limit in shear beams while increasing load bearing capability. The results obtained provide important information that will shed light on new designs.
Citation - WoS: 4
Citation - Scopus: 4
Use of Waste Steel Fibers From Cnc Scraps in Shear-Deficient Reinforced Concrete Beams
(Techno-Press, 2023) Kalkan, İlker; Özkılıç Yasin Onuralp; Aksoylu, Ceyhun; Mydin, Md Azree Othuman; Martins, Carlos Humberto; Hakeem, Ibrahim Y.; Işık, Ercan
The present paper summarizes the results of an experimental program on the influence of using waste lathe scraps in the concrete mixture on the shear behavior of RC beams with different amounts of shear reinforcement. Three different volumetric ratios (1, 2 and %3) for the scraps and three different stirrup spacings (160, 200 and 270 mm) were adopted in the tests. The shear span-to-depth ratios of the beams were 2.67 and the stirrup spacing exceeded the maximum spacing limit in the building codes to unfold the contribution of lathe scraps to the shear resistances of shear-deficient beams, subject to shear-dominated failure (shear-tension). The experiments depicted that the lathe scraps have a pronounced contribution to the shear strength and load-deflection behavior of RC beams with widely-spaced stirrups. Namely, with the addition of 1%, 2% and 3% waste lathe scraps, the load-bearing capacity escalated by 9.1%, 21.8% and 32.8%, respectively, compared to the reference beam. On the other hand, the contribution of the lathe scraps to the load capacity decreases with decreasing stirrup spacing, since the closely-spaced stirrups bear the shear stresses and render the contribution of the scraps to shear resistance insignificant. The load capacity, deformation ductility index (DDI) and modulus of toughness (MOT) values of the beams were shown to increase with the volumetric fraction of scraps if the stirrups are spaced at about two times the beam depth. For the specimens with a stirrup spacing of about the beam depth, the scraps were found to have no considerable contribution to the load capacity and the deformation capacity beyond the ultimate load. In other words, for lathe scrap contents of 1-3%, the DDI values increased by 5-23% and the MOT values by 63.5-165% with respect to the reference beam with a stirrup spacing of 270 mm. The influence of the lathe scraps to the DDI and MOT values were rather limited and even sometimes negative for the stirrup spacing values of 160 and 200 mm.