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Öğe A reuse study from Nigde, Turkey: the conversion of industrial ash to geopolymer(TAYLOR & FRANCIS INC, 2016) Dogan-Saglamtimur, Neslihan; Bilgil, Ahmet; Demir, Merve; Yilmaz, Mehmet Lider; Polat, Serkan; Ozen, Erol; Dordu, HalilCoal is used to generate power for industrial operations. Two types of industrial ashes, including fly and bottom ash, which are solid residues arising from coal burning, are dumped to the landfill of Nide from a selected large-scale international firm named as Goknur A.S in Nide, Turkey with no care for reuse. Geopolymer production was chosen from different alternatives of productive reuse of these waste materials. The properties of the geopolymers are dependent on source materials. Therefore, the first part included elemental analysis of ashes, sieve analysis of them, compacted bulk density analysis of them, and reaction affinity of them. The chemical composition of industrial ash used in this study contained Si and Al accompanied by Ca and Fe. This character has important implications on the potential for productive reuse and reaction potential of these waste materials. The second part of the research is planned to include ashes analysis for calculation of efficiency of combustible matter, experiment of obtaining samples from ashes in different thermal processes, activation of ashes with sodium hydroxide and sodium silicate, activation of ashes with Portland cements, pressure and resistance evaluations for geopolymer samples, water absorption experiment to them, and porosity experiment for them. Considering pressure and resistance, water absorption and porosity experiments, by only a few studies in the literature, higher-strengthened geopolymer is produced at temperatures of 100 and 150 degrees C.Öğe An experimental study on desalination at vacuum environment under low pressure and low condensation temperatures(Elsevier Science Bv, 2017) Bilgil, Ahmet; Hirlakoglu, BurhanEarth's current lack of clean water has necessitated a search for new water sources; desalination of the sea water has been regarded as the best solution. Many techniques have been developed to make sea water into drinking and utility water. Recently, clean water production by the condensation of evaporated salt water at low pressure is one of the commonly applied techniques. Low pressure is obtained by a natural vacuum and renewable energy using a vacuum pump. In the study, system efficiency was examined for desalination at low pressure formed by vacuum pump at 0, -15 or -25 C-omicron condensation temperatures. The volume of desalinated water was measured for each evaporation temperature at 45, 50, 55 and 60 C-omicron, and the efficiency for a given volume of desalinated water at decreased temperatures at condensation temperatures below 0 C-omicron. In each experimental group, salt water could be purified by an average of 99.6%. However, according to the data obtained at 0, -15 or -25 C-omicron condensation temperatures, it was determined that decreasing the condensation temperature to -25 C-omicron was redundant: a similar efficiency could be obtained using less condensation energy at 0 C-omicron. (C) 2017 Elsevier B.V. All rights reserved.Öğe Application of numerical analysis for investigation of relationship between slump values and other rheological properties of fresh concrete(ACADEMIC JOURNALS, 2010) Bilgil, Ahmet; Ozturk, Baki; Samandar, AyhanThe main concern in working with fresh concrete is the workability during filling of formwork. In this study, the mechanism of segregation during the filling of fresh concrete into formwork is numerically investigated considering the rheological properties of fresh concrete. A mathematical model, which considers fresh concrete as a non-Newtonian fluid that, is used for the investigation of relationship between slump values and rheological properties of fresh concrete. The aggregates are considered as Lagrangian particles whose trajectories determine segregation. This study will provide an insight to the relationships between workability and various rheological parameters of fresh concrete that is, yield stress, segregation, viscosity during filling of fresh concrete into formwork. The relationships between workability and rheological properties during the fill of fresh concrete for both concrete mixtures with no admixtures (MC) and concrete mixtures with admixtures (MCS) are investigated. MCS concrete mixture includes super-plasticizers for the same composition of MC. Cylindrical formworks for three different heights of 50, 100 and 150 cm are employed. It is observed that MCS mixtures have higher slump values and less aggregate segregation (%) compared to MC mixtures for the same compositions of fresh concrete. It is found that, slump values decrease as yield stress increases for both MC and MCS fresh concrete mixtures. When MCS mixtures are used, there is a significant reduction in yield stress compared to MC mixtures.Öğe ATIK KAZAN ALTI KÜLÜ VE POMZA ELEK ALTI ATIĞINDAN GEOPOLİMER YAPI MALZEMESİ ÜRETİMİ(2018) Sağlamtimur, Neslihan Doğan; Bilgil, AhmetPomza üretimi sırasında elek altı olarak tarif edilen ince malzeme açığa çıkmaktadır ve atık malzemedurumundadır. Endüstrilerde kömür yakılması sonrası açığa çıkan kazan altı külü de depolanamaz bir atıktır. Buçalışmada atık değerlendirme amacıyla bu iki tip atık, alkali bir aktivatör olan sodyum hidroksit (NaOH) ileaktive edilerek geopolimer yapı malzemesi üretilmiştir. Deneysel çalışmada %50 atık kazan altı külü(AKAK)+%50 pomza elek altı atığı (PEAA) karıştırılarak oluşturulan atık dolgu malzemesine ağırlıkça %10, 15,20 ve 25 oranında NaOH ilave edilmiştir. Numuneler 70, 100 ve 150 °C’ye ayarlanan etüvde 24 saat süresincekürlenmiştir. Daha sonra numunelerin fiziksel ve mekanik özellikleri belirlenmiştir. Basınç dayanım değerlerinegöre optimum sonuç, %20 NaOH aktivatörlü 100 °C’de kürlenen numunede 16,5 MPa olarak bulunmuştur.Basınç dayanımlarında 28 günün sonunda 7 günlük değerlere göre %6-9 oranında artış gözlenmiştir. Su emmeve porozite değerlerinde, diğer yapı malzemelerine benzer sonuçlar elde edilmiştir. Atık malzeme esaslı NaOHaktivatörlü numunelerden dış tesirlere dayanıklı geopolimer yapı malzemesi üretilebilmiştir.Öğe Determination of Physical and Mechanical Properties of Porous Blocks (Bricks) Produced with Brick Clay(Gazi Univ, 2024) Bilgil, Ahmet; Ari Polat, Tuba; Simsek, Osman; Yesilyurt, ErguenClay brick has recently become a very inevitable product for the construction industry due to the being a sustainable and relatively cheaper material especially with the parallel of developments on foam-forming agents. These bricks have two main problems. These are high unit volume weight and thermal conductivity. In this study, an expansion agent was added to the brick raw material to reduce the unit weight of the brick and to increase the thermal insulation. Samples were produced by adding a mixture of expanding at certain rates. The produced samples were fired at 850, 900, 950, 1000, 1050 and 1100 oC to obtain 100x100x100 mm bricks. The unit volume weight, water absorption, void ratio, compressive strength, compressive strength after freezing-thawing and thermal conductivity properties of the produced bricks were investigated. According to the data obtained in the research, the optimum expansion chemical ratio is 15%. The most suitable firing temperature was determined as 1100 oC. The samples produced with 15% expander at 1100 degrees C, unit volume weight 744 kg/m3, water absorption 31.83%, void ratio 36.88 %, compressive strength 6.93 MPa, compressive strength after freezing-thawing 5.10 MPa and thermal conductivity 1,=0.16 W/mK.Öğe Eco-Friendly Fired Brick Produced from Industrial Ash and Natural Clay: A Study of Waste Reuse(Mdpi, 2021) Dogan-Saglamtimur, Neslihan; Bilgil, Ahmet; Szechynska-Hebda, Magdalena; Parzych, Slawomir; Hebda, MarekBottom ash (BA) is an industrial solid waste formed by the burning of coal. The environmental problems and storage costs caused by this waste increase with every passing day. In this study, the use of BA as an additive (clay substitute) in fired brick production was investigated. The study consisted of two stages. In the first stage, cylinder blocks were produced from clay used in brick production. The second stage was the examination of the experimental substitution of clay with 10, 20, 30 and 40% BA. Samples were fired at 900, 1000, 1100 and 1150 degrees C to produce fired brick samples. The unit weight, compressive strength (before and after freeze-thawing) and water absorption were analyzed for the samples. The unit weight values decreased in the samples containing BA. The mechanical properties met the conditions prescribed in the relevant standards; i.e., all of the samples fired at 1100 and 1150 degrees C had a sufficient compressive strength over 20 MPa. The high potential of fired bricks for the construction industry was proved. BA can be used as a clay substitute, while the developed protocol can be used to effectively produce fired bricks.Öğe Eco-Geopolymers: Physico-Mechanical Features, Radiation Absorption Properties, and Mathematical Model(Mdpi, 2022) Dogan-Saglamtimur, Neslihan; Bilgil, Ahmet; Erturk, Sefa; Bozkurt, Vakkas; Suzgec, Elif; Akan, Arife Gozde; Nas, PervinWaste ashes and radiation are hazardous environmental and health factors; thus, a lot of attention is paid to their reduction. We present eco-geopolymer building materials (GPBMs) based on the class F fly ashes (FFAs) from thermal power plants (TPPs) and their implementation as a barrier against radioactive radiation. Different methods of production, ratios of FFA to alkali activator, and temperatures of curing were tested. Small spherical particles and higher content of SiO2 resulted in developed surface area and higher reactivity of Isken TPP FFA than Catalagzi TPP FFA. Lower activator concentration (10% vs. 20%) and curing temperature (70 vs. 100 degrees C) caused an increase in GPBM compressive strength; the highest value was measured as 93.3 MPa. The highest RA was measured for GPBMs, provided alkali activator ratio (Na2SiO3/NaOH) was >2 and its concentration was 20%. The mathematical model developed in this study proved FFA quantity, and thus GPBM mechanical properties, as key factors influencing RA. In the light of these results, the lightweight GPBMs can be excellent materials for the construction sector dedicated to immobilization, storage, and disposal for radionuclides or barriers against radiation; however, multiple steps of their production require careful optimization.Öğe EFFECT EFFECT OF FLY ASH CONTRIBUTION TO THE PHYSICAL AND MECHANICAL PROPERTIES OF CEMENTED PUMICE-BASED LIGHTWEIGHT WALL MATERIAL(Parlar Scientific Publications (P S P), 2017) Dogan-Saglamtimur, Neslihan; Bilgil, Ahmet; Yildirim, Gamze; Bay, Tugce; Doguc, Unal; Erkekli, KubraIn this study, using CEM I and CEM II type cements in different mixing ratios, pumice-based lightweight wall material with the contribution of fly ash (FA) was produced so as to evaluate the likely use of this waste material in the construction sector. Physical and mechanical properties were determined in the samples. This study consists of two stages. In the first stage, pumice in 0-4 mm size was used as coarse aggregate. The average axial compressive strength (ACS) values of samples obtained by using only pumice were 9.2 and 11.7 MPa for Bims Concrete 40 (BC40) and BC80 in CEM I, 5.05 and 10.6 MPa for BC40 and BC80 in CEM II, respectively. In the second stage, FAs were added (25, 50, 75 and 100% in weight) as fine aggregates. The ACS values of samples obtained by using FA additive in different ratios ranged from 4.15 to 5.2 MPa for BC40 in CEM I, 3.0 to 3.45 MPa for BC40 in CEM II, respectively, on the other hand, they ranged from 7.4 to 8.7 MPa for BC80 in CEM I, and 4.9 to 6.8 MPa for BC80 in CEM II, respectively. Turkish and European (TS-EN) standards were used to do experiments and interpret the results.Öğe Process Development of Fly Ash-Based Geopolymer Mortars in View of the Mechanical Characteristics(Mdpi, 2021) Oz, Hatice oznur; Dogan-Saglamtimur, Neslihan; Bilgil, Ahmet; Tamer, Aykut; Gunaydin, KadirThis study aimed to determine the effects of design parameters, including the liquid/solid ratio (L/S), Na2SiO3/NaOH weight ratio, and curing temperature, on class F fly ash-based geopolymer composites. For this purpose, two disparate sources of fly ash were supplied from catalagzi (FA) and Isken Sugozu (FB) Thermal Power Plants in Turkey. Two different L/S ratios of 0.2 and 0.4 were used. The Na2SiO3/NaOH ratios in the alkaline solutions were 1, 1.5, 2, 2.5, and 3 by weight for each type of geopolymer mixture. Then, 40 different mixes were cured at two specific temperatures (70 degrees C and 100 degrees C) for 24 h and then preserved at room temperature until testing. Thereafter, the physical water absorption properties, apparent porosity, and bulk density were examined at 28 days on the hardened mortars. Additionally, compressive and flexural tests were applied to the geopolymers at 7, 28, and 90 days. It was found that the highest compressive strength was 60.1 MPa for the geopolymer manufactured with an L/S of 0.2 and Na2SiO3/NaOH ratio of 2. Moreover, the best thermal curing temperature for obtaining optimal strength characteristics was 100 degrees C for the FB.Öğe Production of geopolymer composites by using different alkaline solution/material ratio(Iop Publishing Ltd, 2019) Dogan-Saglamtimur, Neslihan; Oz, Hatice Oznur; Bilgil, Ahmet; Suzgec, Elif; Vural, TurkanThis study reports an experimental program to optimize mix design parameters of fly ash-based geopolymer engineering composites. Fly ash (FA) supplied from Catalagzi Thermal Power Plant (Zonguldak, Turkey) and Rilem Cembureau Standard Sand were used together with a constant ratio of 0.50 for producing geopolymer. In the first step, two different alkaline solution/material ratio (FA+standard sand) (L/M) were determined as 0.20 and 0.40, respectively. After that, sodium silicate ((Na2SiO3) and 12M sodium hydroxide (NaOH) were utilized at a ratio of 1, 2, and 3, respectively. 6 mixtures obtained by using different design parameters were cured at 70 degrees C for 24 hours, respectively, and then they were stored at room temperature until testing age. While the physical properties of the samples were measured by the bulk density and water absorption tests at 28 days, mechanical properties were tested via the compressive and flexural strength tests at 90 days, respectively. The results indicated that the highest compressive strength for geopolymer materials was found as 36.5 MPa in the mixture produced with the ratios of L/M=0.2 and Na2SiO3/NaOH=2 (by weight). However, less alkali reaction caused by using excessive activator solutions decreased the strength characteristics of geopolymer.
