The effect of occupational choice on job satisfaction and occupational accidents in the construction sector: A case study on Rize and Çorum in Turkey

The construction sector is a sector that employs a significant amount of employees in Turkey and appeals to many branches of work and professions. In Turkey, the construction sector ranks first in the statistics of occupational accidents, with the highest fatality every year. In this study, how the construction workers choose their profession in Turkey, whether they have professional qualification certificates, the relationship between career choice and job satisfaction, and the perceptions of workers in the construction sector about occupational accidents were determined through questionnaires. The questionnaires were applied to 72 construction workers working at four different construction sites. The prepared questionnaires are determined how the construction workers' choice of occupation affected their job satisfaction using a fivepoint Likert scale (strongly disagree, disagree, undecided, agree, strongly agree). The average and standard deviation of the answers given by the construction workers to the questionnaires were found. The relationship between job choice and job satisfaction, between job satisfaction and occupational accident, was determined by correlation analysis. As a result of the study, it has been determined that other people choose a significant portion of the construction workers in Turkey. The job satisfaction of the construction workers who desire a profession is higher. Most of the construction workers working in Turkey perceive work accidents as death or severe injury that will require hospital treatment

The effect of the obsidian of the rize region on the hydrating heat of cement

Bu çalışmada, Rize yöresi obsidyeninin çimentonun hidratasyon ısısını nasıl etkilediği araştırılmıştır. Çimentoda yaygın olarak kullanılan mineral katkılardan uçucu kül ve yüksek fırın cürufunun çimentodaki hidratasyon ısısına etkileri ile karşılaştırılmıştır. Obsidyen, uçucu kül ve yüksek fırın cüruflu çimentoların basınç dayanımları ölçülmüştür. Çalışma sonucunda Rize yöresi obsidyeninin çimentonun hidratasyon ısısını düşürmekte, basınç dayanımı açısından olumsuz bir etkiye neden olmamaktadır. Obsidyen, çimentoda hidratasyon ısısı ve basınç dayanımı açısından uçucu kül ve yüksek fırın cürufuyla benzer etkilere göstermektedir.In this study, the effect of obsidian of Rize region on the hydration heat of cement was investigated. It was compared with the effects of fly ash and blast furnace slag on the hydration heat in cement. The compressive strengths of obsidian, fly ash and blast furnace slag cements were measured. As a result of this study, the obsidian of Rize decreases the hydration temperature of cement and does not cause a negative effect in terms of compressive strength. Obsidian shows similar effects with respect to fly ash and blast furnace slag in terms of heat and compressive strength of hydration in cement.

Estimating the compressive strength of fly ash added concrete using artificial neural networks

The aim of this study is to develop an artificial intelligence that predicts the compressive strength of fly ash substituted concretes using material mixing ratios. Within the scope of the study, 5 different fly ash mixed concrete samples were estimated. The strength values were estimated using artificial neural networks before the produced samples were subjected to the pressure test. In order to develop the artificial neural network, it is introduced as a dataset of 1030 different mixing ratios consisting of experimental results in the existing literature. In order to estimate the compressive strength, varying ratios of 8 different materials such as water, cement, fly ash entering the mixture are analyzed. As a result of the study, it has been observed that the predictions made using artificial neural networks are very close to the strength values obtained from the experiment

Pozzolanic effect on the hydration heat of cements incorporating fly ash, obsidian, and slag additives

Made up of an engineered mix of ordinary Portland cement (OPC) with artificial pozzolans such as trass, fly ash, and slag, the blended cements have been intensely employed within cementitious materials. The main reasons behind this intensive use can be clarified by enhanced workability/strength, the high resistance to chloride/sulfate, reduced permeability/alkali-silica reaction, and a drop in the heat generated by cement's hydration. The use of cementitious blends within concrete not only offers durable products but also cuts climate impact by energy saving and falling CO2 emissions. This study presents pozzolanic effect on the hydration heat of cements incorporating fly ash, obsidian, and slag additives. The blended cements were manufactured by three different replacement ratios of 20%, 30%, and 50%. The change in the hydration heat of obsidian-, fly ash-, and slag-based cements was observed by several Turkish standards (TS EN 196-8 and TS EN 196-9). Mortars were used for determining the uniaxial strengths of obsidian-, fly ash-, and slag-based cements. The results show that cement's hydration heat decreases as the rate of additives (e.g., obsidian) increases from 20% to 50%. The cement's fineness greatly affects its hydration heat. Increasing the refinement of pozzolanic material to a certain level (30%) leads to an increase in the hydration temperature. After reaching this level, there is no clear relation between the fineness and the replacement rate of pozzolans. As a result, the findings of this work will provide a good understanding of artificial pozzolans on performance and quality of obsidian-, fly ash-, and slag-based cements

Taşıyıcı sistem boyutlarının ve malzeme özelliklerinin birinci doğal titreşim peryoduna etkileri

Bu tezin, veri tabanı üzerinden yayınlanma izni bulunmamaktadır.ÖZET Anahtar Kelimeler: Çerçeveler, Yapısal Analiz, Binanın birinci doğal titreşim peryodu. Bu çalışmanın amacı, çerçeveli binalarda sistem boyutlarının ve malzeme özelliklerinin binanın birinci doğal titreşim peryodu üzerindeki etkilerini araştırmaktadır. Birinci bölümde problemin tanıtımı, amacı, kapsamı ve çözümlerde kullanılan program hakkında bilgi verilmiştir. İkinci bölümde deprem etkisindeki yapılar, deprem yönetmeliği, yükler ve çözümde kullanılan metodlar belirtilmiştir. Üçüncü bölümde betonarme yüksek binalarda dinamik dış etki hali, genel hareket denklemleri ve serbest titreşim hakkında bilgi verilmiştir. Dördüncü bölümde sistem boyutlarının ve malzeme özelliklerinin değişmesi durumundaki binaların birinci doğal titreşim peryotları hesaplanmıştır. Beşinci bölümde binaların birinci doğal titreşim peryotları grafiklerle sunulmuştur. Altıncı bölümde hesaplanan değerler bağıntılarla ifade edilmiştir. Yedinci bölümde incelemede bulunan hususlar kısaca özetlenmiştir.XI THE AFFECTS OF THE BEARING SYSTEM DIMENSIONS AND MATERIAL SPECIFICATIONS ON THE FIRST NATURAL VIBRATION PERIOD OF THE BUILDING SUMMARY Key Words: Frames, Construction Analysis, First Natural Vibration Period of the Building. The aim of this study is to analyse the affects of the system dimmensions and the material specifications of the framed buildings on the first natural vibration period of the building. In the first section, knowledge regarding the introduction, aim and the scope of the problem, and the program used for the solution are given. In the second section, the buildings under the earthquake influence, earthquake regulations, charges and the methods used in solution are given. In the third section, knowledge regarding the dynamic external affect status of the reinforced concrete high buildings, general movement equations and free vibration are given. In the fourth section, the calculations -when the system dimensions and material specifications are changet- of the first natural vibration periods of buildings are made. In the fifth section, the graphics of the first natural vibration periods of buildings are given. In the sixth section, the calculated values are introduced with relations. In the seventh section, a summary of the issues explained are given

Pozzolanic properties of trachyte and rhyolite and their effects on alkali-silica reaction

The alkali-silica reaction (ASR) is a highly complex chemical reaction which causes damage to concrete and thus adversely affects the durability and service life. Significant damage can occur in concrete structures due to cracking because of the chemical reactions taking place. Various mineral and chemical additives have been used so far to mitigate ASR and/or to reduce its adverse effects. In this study, ground trachyte and rhyolite provided from Rize-Cagrankaya region, Turkey, were used to investigate their effectiveness in controlling ASR-induced damage by substituting them with cement at certain ratios. In this context, initially the possible use of trachyte and rhyolite as pozzolanas was determined in accordance with BS EN 450-1 and TS 25 standards by considering their pozzolanic activities and then their effectiveness in mitigating the ASR was evaluated as per ASTM C 1567-13. In experimental study, blends of trachyte and rhyolite were prepared by substituting them by cement at 25%, 35%, and 50% percentage. Totally 7 mixes were prepared and three samples of 25x25x285 mm mortar bars were prepared from each batch. The length changes of the mortar bars were determined at the end of 3, 7, 14 and 28 days of exposure. SEM, along with XRD analyses were performed to examine and elementally determine the ASR products that have been formed. The results obtained have shown that ground trachyte and rhyolite used in this study can be used as pozzolanas in concrete and they can also significantly mitigate ASR-induced damage as the substitution ratio increases

Determination of natural radioactivity levels of some concretes and mineral admixtures in Turkey

Sirin, Murat/0000-0001-6864-752XWOS: 000343763700041Nine concrete samples with or without mineral admixtures have been analyzed for their naturally occurring radionuclide of Ra-226, Th-232 and K-40 using HPGe gamma spectrometry. Also, concrete raw materials such as aggregate, cement, fly ash and blast furnace slag have been measured. the radioactivity values of Ra-226, Th-232 and K-40 in fly ash and those of Ra-226 in blast furnace slag are higher than the corresponding world mean specific activities values which are 50, 50 and 500 Bq kg(-1) for Ra-226, Th-232 and K-40, respectively. the concretes activity concentrations have been found to change with supplementary cementitious materials of the concrete samples. This may be attributed to containing different proportions of different mineral additives such as fly ash and blast furnace slag which were found to contain high natural radionuclide concentrations according to the rest of raw material samples. in addition, radium equivalent activities (Ra-eq), gamma-index (I-gamma), alpha-index (I alpha), absorbed dose rate in air (D) and annual effective dose associated with the natural radionuclide were calculated to assess the radiation hazard of the natural radioactivity in the concrete mixture samples. the concentration of the natural radionuclides and the radium equivalent activity obtained in the present study are compared with the previous results. From these results, it can be seen that these building materials do not pose significant radiation hazards

Determination of Natural Radioactivity Levels of Some Concretes and Mineral Admixtures in Turkey

Sirin, Murat/0000-0001-6864-752XWOS: 000343763700041Nine concrete samples with or without mineral admixtures have been analyzed for their naturally occurring radionuclide of Ra-226, Th-232 and K-40 using HPGe gamma spectrometry. Also, concrete raw materials such as aggregate, cement, fly ash and blast furnace slag have been measured. the radioactivity values of Ra-226, Th-232 and K-40 in fly ash and those of Ra-226 in blast furnace slag are higher than the corresponding world mean specific activities values which are 50, 50 and 500 Bq kg(-1) for Ra-226, Th-232 and K-40, respectively. the concretes activity concentrations have been found to change with supplementary cementitious materials of the concrete samples. This may be attributed to containing different proportions of different mineral additives such as fly ash and blast furnace slag which were found to contain high natural radionuclide concentrations according to the rest of raw material samples. in addition, radium equivalent activities (Ra-eq), gamma-index (I-gamma), alpha-index (I alpha), absorbed dose rate in air (D) and annual effective dose associated with the natural radionuclide were calculated to assess the radiation hazard of the natural radioactivity in the concrete mixture samples. the concentration of the natural radionuclides and the radium equivalent activity obtained in the present study are compared with the previous results. From these results, it can be seen that these building materials do not pose significant radiation hazards