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Öğe Assessments of Masonry Buildings and Historical Structures during the 2020 Sivrice-Elaz?? Earthquake(Budapest Univ Technology Economics, 2023) Ozmen, Alper; Maras, Muslum Murat; Ayaz, Yasar; Sayin, ErkutTurkey is located on a seismically active region. The active fault zones, primarily the North Anatolian Fault and East Anatolian Fault, constitute a center to the movements. On 24 January 2020 at local time 20:55, an earthquake of Mw = 6.8 struck Sivrice, Elazig located in eastern part of Turkey. After this main shock, 1185 aftershocks were recorded until February 8, 2020. The main event resulted in 41 human casualties and 1632 injured. Also, 45 people were salvaged from the debris. The earthquake mostly affected to Elazig and Malatya provinces. 633 buildings were demolished, 10492 buildings were severely damaged, 2161 buildings were moderately damaged, and 16046 buildings were slightly damaged in the affected region. This paper focus on evaluating the damages and failures of masonry, adobe, and historical structures in the affected areas around Elazig and Malatya provinces.Öğe Characterization of performable geopolymer mortars for use as repair material(Ernst & Sohn, 2021) Maras, Muslum MuratHeritage masonry constructions constitute an important percentage of the structures in many countries. These structures are highly vulnerable to environmental changes (such as earthquakes), and significant losses in masonry historical constructions occur even in a moderate earthquake. For this reason, damage assessment studies of these structures before earthquakes are of great importance. After an earthquake, historical buildings in Turkey were examined and it was found that many buildings underwent damage. In these structures, damage occurs during the earthquake due to the use of low-quality materials and a lack of sufficient connections between the layers. In these buildings, damage especially occurs in the parts that undergo restoration. Since low-strength repair mortars are generally used in the restored sections, wide cracks have occurred in the building elements under the effect of earthquakes. This study aimed to produce alternative materials that could be used as geopolymer binders in restorated buildings. The mechanical, physical, and microstructural characteristics of the geopolymer samples were investigated in detail using laboratory tests. As a result, the strength of geopolymer repair materials with 8 M and 5% calcium hydroxide (Ca[OH](2)) was very high when compared with other values. High-strength compatible alternative geopolymer repair mortars that could be used for restoration were produced. For this reason, mortar is considered a significant application for repairing and strengthening buildings.Öğe Experimental behavior of injected geopolymer grout using styrene-butadiene latex for the repair and strengthening of masonry walls(Sage Publications Inc, 2021) Maras, Muslum MuratUnreinforced masonry buildings in the historic centers of the world have often been overlooked for centuries without any protection. These buildings demonstrate low resistance under external effects, especially against earthquakes. Earthquakes cause serious damage to the buildings and even the collapse of structures as a result of seismic stimulation from the impact of pounding with structural impacts. For this reason, it is of great importance to repair and strengthen damaged masonry structures. This study investigated the testing of masonry wall specimens produced from different kinds of masonry units with various types of mortar. Then, geopolymer grouts with high mechanical properties were produced by using alkali activation and industrial products. The experimental performance of strengthened masonry wall samples was determined using the optimum geopolymer grout in vertical compression tests. The behavior, failure mode, and crack pattern of the masonry wall samples were determined under loading systems. Experimental results demonstrate that the use of additive styrene-butadiene (SB) latex geopolymer grouts on damaged walls increased the load-carrying capacity and ductility significantly compared to the corresponding values of samples before initial failure. All of the strengthened walls failed through the de-bonding failure mode, and no visible damage was observed on the samples. Consequently, geopolymer grouts displayed many advantages over conventional repair materials due to their high viscosity, compressive strength, eco-friendliness, and excellent resistance.Öğe Fabrication of Novel Geopolymer Grout as Repairing Material for Application in Damaged RC Beams(Springer Int Publ Ag, 2022) Kantarci, Fatih; Maras, Muslum MuratIn this study, a new grouting composite, called geopolymer grout, with high compressive strength (> 107 MPa, cured at ambient conditions) was developed and injected into damaged reinforced concrete (RC) beam. This investigation was planned in two steps: (1) determination of optimum geopolymer grout composite depending on viscosity, compressive strength, and SEM findings; (2) injection of optimum geopolymer grout to damaged RC beam. Geopolymer grouts were fabricated with different NaOH concentrations (i.e., 8, 10, and 12 M) and Ca(OH)(2) contents (1, 3, 5 and 7% of slag weight). A remarkable advance in fresh and hardened characteristics of geopolymer grouts was acquired with changing of NaOH concentration and Ca(OH)(2) content. A reference RC beam was subjected to bending test and the load-displacement curve was obtained. The determined optimum geopolymer grout was injected into this damaged RC beam and exposed to reloading test. The strengthened RC beam specimen was compared with reference RC beam in terms of failure modes, load capacity and crack patterns. After damaged RC beam was strengthened, it showed higher mechanical performance compared to reference RC beam. The experimental findings revealed that geopolymer grouts could be a suitable alternative for repair and strengthening of damaged RC beam due to their low viscosity, eco-friendliness, good bonding and superior compressive strength.Öğe Fire resistance of geopolymer concrete produced from Elaz ferrochrome slag(Wiley, 2016) Turkmen, Ibrahim; Karakoc, Mehmet Burhan; Kantarci, Fatih; Maras, Muslum Murat; Demirboga, RamazanThis paper presents the effect of elevated temperatures up to 700 degrees C on compressive strength and water absorption of two alkali-activated aluminosilicate composites (one of them is river sand aggregate geopolymer concrete; the other one is crushed sand aggregate geopolymer concrete) and ordinary Portland cement based concretes. To obtain binding geopolymer material, Elaz ferrochrome slag was ground as fine as cement, and then it was alkali activated with chemical (NaOH and Na2SiO3). Geopolymer concrete samples were produced by mixing this binding geopolymer material with aggregates. At each target temperature, concrete samples were exposed to fire for the duration of 1h. Fire resistance and water absorption of geopolymer and ordinary Portland cement concrete samples were determined experimentally. Experimental results indicated that compressive strength of geopolymer concrete samples increased at 100 degrees C and 300 degrees C temperatures when compared with unexposed samples. In geopolymer concrete samples, the highest compressive strength was obtained from river aggregates ones at 300 degrees C with 37.06MPa. Water absorption of geopolymer concrete samples increased at 700 degrees C temperature when compared with unexposed samples. However, a slight decrease in water absorption of concrete samples was observed up to 300 degrees C when compared with unexposed samples. SEM and X-ray diffraction tests were also carried out to investigate microstructure and mineralogical changes during thermal exposure. Copyright (c) 2016 John Wiley & Sons, Ltd.Öğe Formulation of a novel nano TiO2-modified geopolymer grout for application in damaged beam-column joints(Elsevier Sci Ltd, 2022) Kantarci, Fatih; Maras, Muslum MuratThe aim of this study is to develop a nano TiO2-modified geopolymer grout and to confirm application in damaged beam-column joints (BCJs). The experimental study was planned in two stages: i) fabrication of an optimal geopolymer grout depending on compressive strength, viscosity, UPV and SEM investigations, ii) injection of the optimal geopolymer grout to damaged BCJ to confirm application. Geopolymer grouts were produced with different NaOH concentrations (8, 10, 12 M) and nano TiO2 contents (5, 10 and 15% of slag weight). The obtained optimal gopolymer grout was injected into the damaged BCJ and subjected to reloading test. Significant improvements in fresh and hardened properties of geopolymer grout samples were provided with modification of NaOH concentrations and nano TiO2 contents. It was also explored that the application of nano TiO2-modified geopolymer grout on the damaged BCJ increased load carrying capacity and ductility in comparison with the reference sample. As a result, a novel eco-friendly geopolymer grout with effective viscosity and high compressive strength was developed and confirmed for utilising in damaged BCJs.Öğe Mechanical and fracture behavior of geopolymer composites reinforced with fibers by using nano-TiO2(Springer Heidelberg, 2021) Maras, Muslum MuratMechanical and fracture behaviors of TiO2-added fiber geopolymer composites (TFGC) were investigated in this study. Mechanical properties of inorganic matrix composites, fiber-reinforced ceramic, and cement-based composites have been studied in different areas of engineering. However, studies about the use of TiO2-added geopolymer composites and the effects of the fiber-matrix interface of TFGC are quite rare in these areas. For this purpose, the compressive, flexural, and tensile strengths and microstructural characterizations of fiber-reinforced geopolymer composites were tested in this study. Results demonstrated that the compressive strengths of steel fiber-reinforced geopolymer composite increased for 0.5%, 1.0%, and 2.0% fiber content compared to the control sample by approximately 96.5%, 90.3%, and 79.2%, respectively. The research findings indicate the high tensile strength of TFGC due to better interface adhesion of fibers. It was also demonstrated that the macro-steel fiber volume fraction of 2.0% of the geopolymer sample exhibited strain hardening in the flexural test. Consequently, it is thought that geopolymer composites will be an important field of application in engineering areas.Öğe Mechanical properties and setting time of ferrochrome slag based geopolymer paste and mortar(Elsevier Sci Ltd, 2014) Karakoc, Mehmet Burhan; Turkmen, Ibrahim; Maras, Muslum Murat; Kantarci, Fatih; Demirboga, Ramazan; Toprak, M. UgurMany researches have been done to investigate using raw materials in the production of geopolymer cements. This paper presents the effects of alkali dosage and silica modulus when using sodium metasilicate solution at different curing conditions on the geopolymerization of ferrochrome slag (FS). As alkali activation for geopolymerization, NaOH and Na2SiO3 solution were used. Geopolymer cement was produced using FS as raw material with 3 different silica modulus (0.50, 0.60 and 0.70) and 4 different Na2O concentrations (4%, 7%, 10% and 12%). The setting time, hydration heat and compressive strength of geopolymer paste samples and compressive strength of geopolymer mortar samples were obtained. The setting time varied between 120 and 870 min, it showed variability depending on Na2O content. The highest 28 day compressive strength of the geopolymer paste samples was obtained from one with Na2O concentration of 7% and silica modulus of 0.70. Geopolymer mortars were prepared for the determination of compressive strength by adding FS:sand:alkali activator ratio 1:2:0.30, 035 and 0.40. The specimens were cured at 60 degrees C and 80 degrees C kept for 20 h and the other mortar samples were stored under laboratory conditions. Compressive strength of the material decreased, when w/b (water/binder) ratio increased. The highest 28 day strength of the geopolymer mortar was obtained at 0.30 w/b ratio and laboratory temperature curing conditions. The hydration heat of geopolymer paste samples was found to be less than normal Portland cements. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were investigated to study the microstructural properties of the geopolymers. (C) 2014 Elsevier Ltd. All rights reserved.Öğe Microstructural Characterization and Mechanical Properties of Volcanic Tuff (Malatya, Turkey) Used as Building Stone for the Restoring Cultural Heritage(Budapest Univ Technology Economics, 2021) Maras, Muslum Murat; Kose, Mehmet Metin; Rizaoglu, TamerOld stone buildings constitute a significant percentage of the residential buildings in many countries. These structures are highly vulnerable, and important losses in masonry structures occur even in moderate earthquakes. Therefore, safety evaluations of these structures have gained significant attention in recent years. In this study, the mechanical, physical and microstructural characteristics of tuff samples used in the old buildings were investigated in Battalgazi within the boundaries of Malatya Province during the Seljuk time. The characteristics of the building materials were examined in detail using in-situ and laboratory tests. Because adequate samples could not be obtained from the historical buildings, quarry areas with the same characteristics were identified. First, original building stone (OBS) used in construction was taken from fallen and unusable blocks. Then, the properties of the restoration building stones (RBS) brought from the quarries were investigated. The RBS samples were also examined using in the laboratory, and the mechanical and microstructural properties of the building components were determined. The dynamic and static moduli of elasticity were determined using ultrasonic pulse velocity and uniaxial compression test. The OBS and RBS samples yielded similar results after the microstructural analyses. Our results showed that the dynamic elastic modulus value was higher than the static elastic modulus value. The results revealed by both methods showed that the static and dynamic elastic moduli were closely linked. The OBS and RBS samples exhibited microlitic porphyritic and vesicular textures and nearly the same mineralogical and textural characteristics.Öğe Optimization of production parameters of novel hybrid fiber-reinforced geopolymer mortar: Application in masonry walls(Elsevier Science Inc, 2023) Buyuktapu, Merve; Maras, Muslum MuratEarthquakes cause heavy damages to occur in masonry walls, largely due to the use of low-strength mortar. The scope of this study aimed to produce a new mortar with higher strength, which does not use cement as a binder, instead of the mortars currently used as a binder. In the first stage, geopolymer mortar samples were prepared and the sample that gave the optimum results selected as the reference mix for fiber mixes. The highest compressive strength value was obtained in mixtures with Na2SiO3/NaOH (10 M) = 2 at mixing ratios. Then, seven different combinations were created for three different fiber types (carbon, glass and PP fiber). Among these mixtures, subjected to compression and flexural test with fiber combination in the produced samples, the mixture with the highest mechanical properties was used in masonry wall production. The compressive and flexural strength values of optimum fiber-reinforced o geopolymer mortar mixture under ambient conditions were obtained as 44.1 and 8.1 MPa, respectively. Significant increases were obtained in the compressive and flexural strengths with the increase in carbon fiber content in hybrid fiber ratios. Then, a uniaxial compression and diagonal test was applied to the walls produced with both normal mortar and geopolymer mortar. When the results are examined, the masonry wall prepared with fiber-reinforced geopolymer mortar (GPM) carried a load of 550 kN under vertical loading system, while the wall prepared with normal mortar carried a load of 147 kN under diagonal test. Through the experiments, it was determined that the walls produced using fiber-reinforced geopolymer mortar have higher shear and compressive strength values than the walls prepared with standard cementitious mortar. While the wall samples produced with cement-based standard mortar collapsed under the uniaxial compression test, the wall samples produced with fiber-reinforced geopolymer mortar showed ductile behavior and no sudden failures occurred under diagonal loading tests.Öğe Production parameters of novel geopolymer masonry mortar in heritage buildings: Application in masonry building elements(Elsevier, 2023) Kutlusoy, Erkay; Maras, Muslum Murat; Ekinci, Enes; Rihawi, BaraaThe aim of this study is to develop an innovative high-strength restoration mortar using recycled materials as an alternative to the mortars used in historical buildings. Compressive strength tests were carried out on the samples and, according to the results, the mortar giving the highest strength was determined as the optimum mixture. The compressive strength, shear strength, displacement and load-carrying capacity values of the masonry units were tested by using the geopolymer mortar with the highest strength among the mortar samples produced. The novelty of this research is that geopolymer repair mortars were produced as an alternative to standard mortars and applied in masonry building units. The results showed that blast furnace slag and brick powder can effectively improve the compressive and bond strength of the geopolymer. In the compressive strength tests performed on the samples, much higher strength results were obtained with geopolymer historical building mortar than standard historical building mortar. In the compressive and shear strength performed on the masonry units, the geopolymer historical building mortar showed higher mechanical properties compared to the standard historical building mortars. When the compressive strength test results are compared, a strength of 1.8 times was observed in the masonry unit (GHB1) produced using geopolymer historical building mortar, compared to the masonry unit (HB1) produced with standard historical building mortar. As a result of the shear strength test, the masonry unit (GHK1) produced with geopolymer mortar demonstrated seven times more load carrying capacity than the masonry unit (HK1) elements produced with standard historical building mortar. Moreover, the masonry arch systems produced with standard historical building mortar showed close load bearing capacity with the geopolymer historical building mortar, but the masonry arch element produced with geopolymer mortar exhibited a more ductile behavior. It has been determined that the use of geopolymer mortars with recycled materials with increasing molarity in masonry arch elements improves the compressive strength and accelerates the geopolymerization mechanism. Innovative highstrength geopolymer mortars used in masonry walls provided good adhesion with the hollow brick, creating a compact structure.Öğe Seismic Assessment of the Historical Sutlu Minaret Mosque(Budapest Univ Technology Economics, 2022) Maras, Muslum Murat; Ozmen, Alper; Sayin, Erkut; Ayaz, YasarHistorical masonry structures that connecting the past to the present have great importance because they represent the experiences and characteristics of various cultures. Therefore, the protection of historical structures is important. In this study, the structural response of the historical masonry Mosque was evaluated through dynamic analyses. For this purpose, the Sutlu Minaret Mosque which is located in Malatya, Turkey, was investigated. The three-dimensional model of the historical mosque was generated with ANSYS software. The material properties of the mosque were obtained with experimental tests. The time history analyses were used to obtain the seismic behavior of masonry mosque. In the time history analyses, six different strong ground motion records, including the 2020 Elazig earthquake, were used. After the analysis, displacement and stress values in the mosque were given. The absolute peak displacement value among these earthquake records was obtained from the 1999 Duzce earthquake and the highest principal compressive and tensile stress values were determined for the 2010 Darfield earthquake. Also, the crack regions which occurred in the mosque after the 2020 Elazig earthquake were compared with the dynamic analysis result of the 2020 Elazig earthquake. The crack regions formed after the Elazig earthquake are similar to the possible crack regions formed after the dynamic analysis.Öğe Structural Behavior of Masonry Panels Strengthened Using Geopolymer Composites in Compression Tests(Springer International Publishing Ag, 2021) Maras, Muslum Murat; Kose, Mehmet MetinUnreinforced masonry panels are the most important supporting elements in many structures, but these building elements are very vulnerable to earthquakes, and serious damage occurs. Many researchers state that the seismic performance of the masonry samples is poor and that these elements should be strengthened. In this study, the structural behavior of the strengthened masonry prism was investigated using Geogrid Geopolymer Panels (GGP) in compression tests. Six stone masonry wallettes were built to characterize them under loading systems, and the behavior of the samples was determined with different geometric strengthening methods (cross, diagonal, and parallel). Samples UCT-M1 and DCT-M1 were unreinforced masonry walls. GGP material was applied across the entire surface of reinforced samples UCT-M2 and DCT-M2. Vertical and diagonal compression tests were applied to the samples according to ASTM C1314-10 and ASTM E519-02, respectively. A linear variable differential transducer was placed on the samples, and the load-displacement curves were determined. As a result, the reinforced masonry walls had higher mechanical strength and load-carrying capacity than the UCT-M1 and DCT-M1 samples. The geopolymer composites prevented the degradation of the UCT-M2 and DCT-M2 samples. Also, the strengthened specimens displayed more ductile behavior, which depends on the failure mode and cracks patterns under the loading systems.Öğe Structural behavior of RC beams strengthened using fiber-reinforced polymer U-jackets(Ernst & Sohn, 2023) Maras, Muslum Murat; Kantarci, FatihThe study aims to identify flexural behavior of RC beams strengthened using three different fiber-reinforced polymers (FRPs) with differential cross-sections configuration (i.e., middle and support sections). The experimental and calculations results of strengthening methods for RC beams were investigated utilizing FRPs under flexural loading. The strengthening FRP materials (CFRP, AFRP, and GFRP) were externally attached to the surface of the samples with U-wrapped shape at the three different regions of the beams. The experimental results were compared with the fiber polymer systems of the American Concrete Institute according to the ACI 440.2R-08 standards. The results demonstrated that RC-9 specimen reinforced using AFRP exhibited higher load capacity performance than the others. The RC beams strengthened at both middle and support area exhibited more ductile behavior, which depends on the failure mode. Less crack formation was seen in the RC-10 beams reinforced with AFRP, both in the middle and in the support area, compared with reference sample. The experiment revealed that FRP U-jackets could be a promotive alternative to improve structural performance greatly and provide reliable and suitable solutions for sustainable buildings.Öğe Structural Performance of Reinforced Concrete (RC) Moment Frame Connections Strengthened Using FRP Composite Jackets(Springer Heidelberg, 2021) Maras, Muslum Murat; Kantarci, FatihThis study investigates structural behaviors of reinforced concrete (RC) moment frame connections strengthened using three different FRPs with different cross section configurations. The novelty of this research is the strengthening of a beam-column connection with FRP composites, where the joint consists of a weak column and a strong one that plays a vital role in the RC element. It is also rare in engineering to use inorganic composites in retrofit configurations (X shape, U shape, and T shape retrofit configurations). That is why we aimed to apply fiber-reinforced composite materials in different configurations (cross, diagonal, and parallel configurations). The experimental performance of strengthened samples was investigated using carbon fiber-reinforced polymer (CFRP), aramid fiber-reinforced polymer (AFRP), and glass fiber-reinforced polymer (GFRP) under loading systems. The strengthened RC specimens (SBWC-2-SBWC-7) were compared with a control specimen (SBWC-1) in terms of load capacity, ductility index, failure modes, and crack patterns. The strengthening of the SBWC-2 and SBWC-3 specimens using CFRP increased the ultimate loads up to 12.5% and 11.4% compared to reference sample, respectively. The first cracks in SBWC-4 and SBWC-5 beam-column joint specimens were found at loads of 35.4 kN and 33.8 kN, respectively. The results indicate that SBWC-2 specimen strengthened by AFRP displayed higher strength and ductile behavior than other specimens, as it depends on failure mode more than its counterparts. The reinforced X shape beam-column connection sample was protected from diagonal cracks. Strengthening with CFRP decreased visible-width shear cracks compared to control samples. The experiments revealed that CFRP composites could be a suitable alternative for greatly improving structural performance and providing suitable and reliable solutions for sustainable structures.Öğe Sulfate resistance of ferrochrome slag based geopolymer concrete(Elsevier Sci Ltd, 2016) Karakoc, Mehmet Burhan; Turkmen, Ibrahim; Maras, Muslum Murat; Kantarci, Fatih; Demirboga, RamazanThis paper presents the study of the performance of a new geopolymer binding material exposed to sulfate attack. Geopolymer binding material was obtained by alkaline activating FS with chemical materials (NaOH and Na2SiO3). Geopolymer concrete samples were produced by mixing this binding material with river sand and crushed sand aggregates. Test specimens were immersed in magnesium sulfate solutions (by weight 3%, 5% and 7%) for various periods of time and the durability of geopolymer concrete was investigated. The residual compressive strength (90 and 180 days), change in weight and length of samples, pH variation of solution and visual appearance of these samples were obtained experimentally. It was concluded that compressive strength of both geopolymer and Ordinary Portland Cement (OPC) based concrete samples decreases with increasing in MgSO4 content and exposure duration. After exposed to 7% MgSO4 solution for 180 days, the minimum decrease in compressive strength was seen 25% in geopolymer concrete samples with crushed sand aggregates. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
