Effect of high temperature on sepiolite – hydraulic lime mortar

Sepiolite is a natural clay mineral consisting of magnesium hydrosilicate. High surface area and micropores which form micro structure of sepiolite play an important role for the sepiolite to be used as a binder in the construction sector. The adsorbed water molecules, which are located in the chemical composition of sepiolite, move away from the structure while temperature goes up. When the temperature reaches 950°C chemical structure of sepiolite becomes impaired. This behavior under high temperature of sepiolite supports the use in the construction industry. Pozzolans such as sepiolite have little binding effect on their own. Therefore lime or cement is used together. The use of lime and sepiolite together in the repair mortars for restoration of historic buildings is one of the recent studies. However authors didn’t encounter a study on high temperature resistance of mortars added with sepiolite. In this study to determine the behavior of mortars at high temperature, mixtures are designed at different rates of sand/binder and sepiolite/hydraulic lime. Specimens were exposed to 400°C and 700°C. The effect of high temperature on the lime mortar was determined, with respect to the loss in unit weight, ultrasonic pulse velocity, compressive strength and bending strength. At the end of the test results, there wasn’t any significant change in physical and mechanical properties of mortars up to 400°C. However above 400°C, negative effects were observed

UTILIZATION OF CHROME ORE CONCENTRATION PLANT TAILINGS AS FINE AGGREGATE IN READY-MIXED CONCRETE

Large amount of the chrome ore concentration plant tailings was discarded during chrome ore mining process. The accumulation of the tailings takes large areas of land for the storage and causes environmental and safety problems. When the annual consumption of the ready mixed concrete per person (approximately 1.5 m3/person) in Turkey is considered, employment of the tailings in the ready-mixed concrete may be a solution for the recovery of the tailings. In addition, using chrome tailings as a substitution for sand to produce ready-mixed concrete is a possible way to solve the resource problem of sand deficiency. The aim of this study is to investigate the utilization of the tailings taken from a chrome ore concentration plant in Eskisehir, Turkey as fine aggregate in ready-mixed concrete production. For this purpose, the tailings were partially replaced with the fine aggregate by the weight at 0, 10, 20 and 30% proportions by weight in the ready-mixed concrete mixtures. Standard curing is applied until the time of test to the 15x15x15 cm cube specimens taken from the mixtures.  The unit weight, compressive strength and ultrasonic pulse velocity values of the cubic specimens were investigated in this study. Performed tests showed that replacing sand to chrome ore tailings has a potential for further investigations. 

Statistical Analysis of Chemical Admixtures Usage for Concrete: A Survey of Eskisehir city, Turkey

AbstractNowadays, the concrete admixtures are widely used in the construction projects. The main types of chemical admixtures can be summarized as plasticizers, accelerating/retarding agents, air entraining agents, waterproofing additives and others such as corrosion inhibitors and colouring agents etc. The benefits derived from the use of chemical admixtures include improved durability, strength, chemical resistance, colouring, reduction in water and cement requirement and enhanced working properties of concrete. Turkey is one of the major consumers in developing countries regarding chemical admixtures. Therefore, this study set out to determine general utilization and consciousness about admixtures through a survey in Eskisehir, Turkey. The survey was performed by 153 construction professionals. The questions about reasons for preference of admixtures, types of preferred admixtures and dosage, beneficial and adverse effects of admixtures, impacts on cost and judicious use of admixtures are included in the survey. A number of statistical analyses are carried out using SPSS on data obtained. According to results, chemical admixtures are used over 70% of the total annual concrete production. The initial expectation of the participants in the use of the admixtures is to improve the properties of the fresh concrete. Additionally, the most preferred admixtures are plasticizers. The ensuing types of admixtures are agents affecting the setting time of concrete. Although the participants’ interest to using chemical admixtures is very remarkable, the awareness on this subject is very deficient. The similar studies can be suggested to apply more comprehensively. Professionals, at any level in the construction sector, need to be informed about the accurate consumption of these agents in order to avoid inappropriate results

Utilization of ceramic waste in the production of Khorasan mortar

Khorasan mortar was used in almost all of the historical structures in the geographical area of turkey. It is still used in the renovation of these structures. Water, lime, baked clay is used in the production of Khorasan by breaking and grinding. Crushed brick and tiles are preferred as baked clay. In this study, the usability of ceramic wastes as baked clay was investigated. An important part of ceramic production is made especially in Eskişehir and its vicinity. 10% of ceramic production shows up as wastes because of various reasons. These wastes which are under 20 mm are crushed in the jaw breakers and these which are under 150 mm are grinned in grinders, transformed to powder and then mixed with hydrated lime and water in various proportions, in this way Khorasan mortars are obtained. In mortar production, crushed ceramic-ceramic powder ratio, ceramic-lime ratio were changed and the most suitable ratios were tried to be found. Samples taken from these mortars which are 4 cm x 4 cm x 16 cm in size are removed after a day from the mold and kept in humid environment. Physical and mechanical properties such as unit weight, ultrasonic pulse velocity, bending strength, compressive strength of the mortar were determined. As a result of the experiments, the unit weights range was between 1.5–1.65 kg/dm3, the ultrasonic pulse velocity rates range from 1.3–1.9 km/h, the range of bending strengths was from 0.25–1.05 MPa, and compressive strength has changed in the range of 7.5–10.5 MPa. With the work done, it is recommended to use a high percentage of lime while using ceramic wastes in the process of producing Khorasan mortar

ATIK ANDEZİT VE MERMER TOZUNUN ÇİMENTO HARÇLARININ DAYANIM ÖZELLİKLERİNE ETKİSİ

The sludge generated during cutting of andesite and marble stones is stored in powder form after drying. Due to the wide usage area and consumption of marble and andesite, the storage problem of these wastes arises. Therefore, it is important to eliminate the storage problems of these wastes and to recover them to the economy. For this purpose, in this study, mortar samples were produced using 5%, 10%, 15% and 20% of waste andesite and marble powder separately instead of cement. Ultrasound pulse velocity, flexural and compressive strength tests were carried out on the produced samples. The experimental results showed that the most suitable substitution rate of marble powder used in this study is 10% and andesite powder 15%. In addition, the highest flexural and compressive strength values were achieved in mortars with 15% andesite powder substitution instead of cement

A NEW APPROACH TO TENSILE TESTING OF GFRP BARS

Tensile testing is a critical procedure for evaluating the mechanical properties of Glass Fiber Reinforced Polymer (GFRP) bars, which emerged as an alternative to traditional steel reinforcement in reinforced concrete structures. While significant research has led to the development of testing standards for GFRP bars, their implementation often necessitates additional specimens and specialized equipment compared to their steel counterparts. This study proposes a new method for conducting GFRP tensile tests using standard equipment designed for conventional structural steel rebar testing. By employing existing devices, our approach offers a practical and cost-effective solution for assessing the tensile properties of GFRP reinforcement. This simplified testing method aims to enhance efficiency, facilitate wider adoption of GFRP bars in reinforced concrete structures, and contribute to the advancement of sustainable construction practices

Effects of sulfasalazine on lipid peroxidation and histologic liver damage in a rat model of obstructive jaundice and obstructive jaundice with lipopolysaccharide-induced sepsis

AbstractBackground: Sulfasalazine, an inhibitor of cyclooxygenase, 5-lipoxygenase, and nuclear factor κB (NF-κB), has been found to alleviate oxidative damage, proinflammatory cytokine production, bile-duct proliferation, neutrophil infiltration, and fibrosis. Therefore, it may have a potential effect in attenuating lipid peroxidation and histologic liver damage in patients with biliary obstruction and biliary obstruction with sepsis.Objective: The aim of this study was to investigate the effect of sulfasalazine on lipid peroxidation and histologic liver damage due to obstructive jaundice (OJ) and to OJ with lipopolysaccharide (LPS)-induced sepsis in an experimental model.Methods: Male Wistar rats, weighing 150 to 220 g, were randomized into 6 groups: OJ; OJ + LPS; OJ + sulfasalazine; OJ + sulfasalazine + LPS (sulfasalazine administered before sepsis); OJ + LPS + sulfasalazine (sulfasalazine administered after sepsis); and sham. Liver malondialdehyde (MDA) and myeloperoxidase (MPO) activities were assessed to monitor lipid peroxidation and neutrophil infiltration in liver tissue. Histologic liver damage was evaluated with hematoxylin-eosin stained slides. Liver tissue NF-κB and caspase-3 expression were studied immunohistopathologically to evaluate lipid peroxidation, liver damage, and hepatocyte apoptosis.Results: Forty-eight rats were evenly randomized into 6 groups of 8. MDA (P = 0.001), MPO (P = 0.001), NF-κB (P = 0.003), caspase-3 expression (P = 0.002), and liver injury scores (P = 0.002) increased significantly in the OJ group compared with the sham group. Compared with the OJ group, MDA (P = 0.030) and MPO levels (P = 0.001), and liver injury scores (P = 0.033) were decreased significantly in the OJ + sulfasalazine group. In the OJ + sulfasalazine + LPS and OJ + LPS + sulfasalazine groups, MDA (P = 0.008 and P = 0.023, respectively) and MPO (both, P = 0.001) were significantly decreased; however, liver NF-κB, caspase-3 expression, and liver injury scores were not significantly different compared with the OJ + LPS group. There was no significant difference between the OJ + LPS + sulfasalazine and OJ + sulfasalazine + LPS groups in regard to all end points when comparing the effects of sulfasalazine administered before or after sepsis.Conclusions: Sulfasalazine was associated with decreased neutrophil accumulation and lipid peroxidation in these rats with OJ. Administration of sulfasalazine before or after LPS-induced sepsis was associated with a reduction in lipid peroxidation and neutrophil accumulation; however, it did not attenuate histologic liver damage. There was no difference between the findings when sulfasalazine was administered before or after sepsis in OJ

Bir vakıf üniversitesi tıp fakültesi hastanesi fiziksel tıp ve rehabilitasyon servisi’nin maliyet yapısı ve analizi

Bu araştırmanın amacı, geçmişte uzun yıllar idari ve mali açıdan kamu müessesesi niteliğinde hizmet veren, günümüzdeyse bir vakıf üniversitesine bağlı Tıp Fakültesi’nin Fizik Tedavi ve Rehabilitasyon (FTR) Anabilim Dalı’na ait bakım ve tedavi servislerinin maliyet yapısı ve analizidir. Çalışmada, Vergi Usul Kanunu ve diğer ilgili mevzuat gereğince tutulan kayıt ve raporlara dayalı muhasebe verileri kullanılmıştır. Bunlar, Microsoft Excel programı kullanılarak geleneksel yöntemlerle çözümlendikten sonra, bilgisayar istatistik programında Korelasyon (ilişki) testi yapılmış, veri güvenliğiyse Alfa testiyle yapılmıştır. ‘Toplam maliyet’in yarısından fazlasının ‘işgücü gideri’nden oluşmasına rağmen, bu iki değişken/gider arasında anlamlı bir ilişki bulunamamıştır

Syndrome of Inappropriate Secretion of Antidiuretic Hormone Cholestasis and Pericardial Effusion Due to Brucellosis Infection: A Case Report

Syndrome of inappropriate secretion of antidiuretic hormone (SIADH) is an extremely rare complication of infectious diseases. A rare case of brucellosis complicated by syndrome of inappropriate secretion of antidiuretic hormone (SIADH) cholestasis and pericardial involvement is reported. A 27-year-old woman was admitted for fever, abdominal pain, and scleral icterus. Her medical history revealed no recent use of diuretic agents. In addition to cholestasis and elevated liver enzymes, euvolemic hyponatremia, hypouricemia, low plasma osmolality, and high urinary osmolality were also detected. Surrenal and thyroid tests were also within normal range. Echocardiography revealed minimal pericardial effusion with normal cardiac functions. The final diagnosis was SIADH due to Brucellosis. Hyponatremia, cholestasis, and pericardial disease were resolved with effective antibrucellar treatment with streptomycine and doxycycline. After completing treatment of brucellosis, there was not any more evidence of cholestasis and pericardial fluid