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Öğe Effect of Colemanite Ore Wastes Utilization on Fresh Properties and Compressive Strength of Cementitious Systems(Springer Heidelberg, 2022) Ozen, Suleyman; Durgun, Muhammed Yasin; Kobya, Veysel; Karakuzu, Kemal; Mardani-Aghabaglou, AliIn this study, the usability of colemanite wastes (CW), in mortar mixtures, was examined in terms of compressive strength, while at the same time it was aimed to evaluate the effects of this waste on the rheological properties of mortar and paste mixtures. Mortar and cement paste mixtures were produced by substituting 1, 3, 5, and 7% of the cement with the CW. Marsh-funnel flow times, mini-slump values, rheological parameters, and setting times of cement paste mixtures containing CW were determined. The time-dependent slump-flow and 1-, 7-, 28-, and 56-day compressive strength values of the mortar mixtures were determined. The microstructures of the specimens were evaluated by using SEM images, and phase analyses were examined with XRD analysis. The results showed that the use of CW negatively affected the fresh state properties and rheological parameters of cementitious systems. However, CW addition decreased the 1-, 7-, and 28-day compressive strength. Only a slight increase was observed in the strength of mixtures containing 5 and 7% CW at 56 days.Öğe Effect of high temperature on polypropylene fiber-reinforced mortars containing colemanite wastes(Elsevier, 2021) Durgun, Muhammed Yasin; Özen, Süleyman; Karakuzu, Kemal; Kobya, Veysel; Bayqra, Sultan Husein; Mardani-Aghabaglou, AliIn this study, the effect of polypropylene (PP) fiber utilization ratio on the fresh and some hardened properties of mortar mixtures containing colemanite waste (CW), which mainly contains B2O3, SiO2 and CaO, containing mortar mixtures were investigated. The 17 mortar mixtures were prepared by replacing 0, 1, 3, 5, and 7 wt% of cement with CW and by adding 0, 0.5, 0.75, and 1% by volume of PP fibers to the control mixture. In all mixtures, water/binder ratio, sand/binder ratio and slump-flow values were kept constant as 0.485, 2.75 and 220 +/- 20 mm, respectively. Water reducing admixture requirement of each mixture was determined to provide the target slump-flow range in mortar mixtures. There was a change in the amount of admixture according to the amount of CW and fiber content in the mixture. The 28 and 56-day water absorption capacity, compressive strength and high temperature resistance of mortar mixtures were determined. Strength reduction of specimens exposed to 300 degrees C and 600 degrees C were compared. In addition, thermal and scanning electron microscopy (SEM) analyses were performed on the specimens. According to the test results, with the increase in the amount CW and PP fiber in the mixtures, the admixture demand to provide target flow value and the 28-day water absorption capacity of the mixtures increased, while the 28-day compressive strengths decreased. However, while there was no significant change in the 56-day water absorption capacity and compressive strength values of the specimens containing CW, the water absorption capacity increased and the compressive strength decreased upon the presence of fiber in the matrix. The specimens containing both of CW and PP fiber showed better performance in terms of high-temperature resistance.Öğe Effect of polypropylene fiber and shrinkage reducing admixture utilization on water absorption of Khorasan mortar(Elsevier, 2022) Kaya, Tugce Isafca; Karakuzu, Kemal; Ozen, Sueleyman; Dogangun, Adem; Aghabaglou, Ali MardaniIt is seen that lime-based mortars are frequently preferred in historical and monumental structures. It is known that damages occur depending on the materials used in the building over time. In restoration works, mortars compatible with the original material of the building should be used. For this reason, the use of lime-based mortars is common during restoration work. Accordingly, attention should be paid to the physical and mechanical properties of the mortar to be produced. This study aims to determine the effect of polypropylene (PP) fiber and shrinkage reducing admixture (SRA) on the water absorption properties, which is used to improve the strength and durability properties of Khorasan mortar. As a result, it was determined that PP fiber utilization increased the water absorption ratio due to the formation of voids in the mortars. However, the use of SRA decreased the water absorption ratio due to its effect on the drying shrinkage behavior of the mortars. In cases where both are used together, the effect of fiber use was more dominant. Copyright (C) 2022 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the Third International Conference on Aspects of Materials Science and Engineering.Öğe Effects of Shrinkage Reducing Admixture and Polypropylene Fiber Utilization on Some Fresh State, Mechanical and Durability Properties of Khorasan Mortar(Taylor and Francis Ltd., 2024) İsafça-Kaya, Tuğçe; Karakuzu, Kemal; Özen, Süleyman; Mardani, Ali; Do?angün, AdemThis study aimed to improve the mechanical and durability properties of Khorasan mortar, a type of lime-based mortar, using polypropylene shrinkage reducing admixture (SRA) and fiber. In addition to the control mixture without fiber and chemical admixture, three series of mixtures were prepared. The first series contains 0.4–0.6-0.8% polypropylene fiber by total volume; the second series contains SRA at the 0.05–0.1-0.15% by binder weight; the third series consists of mixtures containing both fiber and the SRA. Within the scope of the study, some fresh state, mechanical and durability properties were determined. The results show that utilization of fiber and SRA reduced the length change depending on drying-shrinkage and mass loss due to abrasion compared to the control mixture. In addition, the 90-day flexural and compressive strength values for all mixtures were lower than the 28-day results. It was determined that the decrease in strength values is less than the control mixture with the utilization of fiber and SRA because of the degradation in drying-shrinkage. © 2022 Taylor & Francis.Öğe Influence of sulfonate and phosphate groups in polycarboxylate ethers on properties of fly ash blended cementitious systems(Elsevier Sci Ltd, 2025) Altun, Muhammet Gokhan; Karakuzu, Kemal; Ozen, Suleyman; Hatungimana, Daniel; Mardani, Ali; El-Mir, Abdulkader; Assaad, Joseph J.This investigation examines the effect of anionic monomer groups in polycarboxylate ether (PCE) superplasticizers on rheology, setting, compressive strength, and water absorption of cementitious systems containing fly ash additions. Five PCEs having the same backbone structure and different anionic groups are synthesized. The carboxylate functional group is replaced with 10 % or 30 % sulfonate or phosphate groups, while the total anionic monomer content, molecular weight, and side chain length are kept constant. Test results showed that the PCEs containing 30 % sulfonate or phosphate functional groups are effective in improving flow and reduce apparent viscosity, particularly in mixtures containing increased fly ash additions. Because of improved adsorption properties, setting times are extended, which consequently reduces the 1-day compressive strength when the carboxylates are gradually replaced by 10 % or 30 % sulfonate or phosphate functional groups. Yet, the late age strengths and water absorption are not affected by such replacements. Data reported in this paper can be of interest to admixture producers and concrete technologists seeking an efficient performance of PCE polymers in fly ash concrete mixtures.Öğe Single and Multi Effects of Polycarboxylate Main and Side Chain Lengths on Setting Time, Viscosity, and Yield Stress of Cementitious Mixtures Containing Fly Ash(Asce-Amer Soc Civil Engineers, 2023) Altun, Muhammet Gokhan; Ozen, Sueleyman; Karakuzu, Kemal; Mardani, Ali; Ramyar, KambizIn this study, polycarboxylate polymers having different main chain lengths, side chain lengths, and main chain and side-chain lengths at constant molecular weight were synthesized. Cementitious mixtures with 0%, 15%, 30%, and 45% fly ash substitution levels were tested with polycarboxylate based admixtures (PCEs). As the main and side chain length of the PCE increased up to a certain value, regardless of the fly ash content, the fluidity of the mixtures was positively affected. However, after a certain length, both the electrostatic and steric effects of the PCE decreased, as the polymers intercalated and flocculated, adversely affecting the flow properties of the mixtures. Regardless of the PCE structure, the use of fly ash adversely affected the setting times and rheological properties of the mixtures.Öğe The Effect of Sulfonate and Phosphate Anionic Monomers of Water Reducing Admixtures on Fresh State and Mechanical Properties of Self Compacting Concrete(Bursa Uludağ Üniversitesi, 2022) Altun, Muhammet Gökhan; Özen, Süleyman; Karakuzu, Kemal; Mardani, AliIn this study, the effect of anionic monomer content of polycarboxylate-ether based water reducing admixture on various fresh and hardened state properties of self-compacting concrete (SCC)mixtures was investigated. For this purpose, in addition to the control admixture whose anionic monomer is 100% carboxylate, 5 different water reducing admixtures were synthesized by replacing the anionic monomer of the control admixture with 10% and 30% sulfonate and phosphate. According to the results, the substitution of the water reducing admixture anionic monomer with sulfonate increases the admixture requirement of the mixtures; had a positive effect on time-dependent flowing performances. In the case of phosphate substitution, the admixture requirement of the mixtures decreased, while the time-dependent flowing performance was adversely affected. The best performance among all mixtures was obtained with 10% sulfonate substituted admixture. The anionic monomer change did not cause any significant changes in the compressive strength, water absorption rates, ultrasonic pulse velocity (UPV) and dynamic elasticity modules of the SCC mixtures.
