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Öğe Prediction of the thermal conductivity of lightweight building materials utilizing backpropagation neural network method(Fırat Üniversitesi, 2015) Oktay, Hasan; Polat, Süleyman; Fidan, ŞehmusThe growing concern about energy consumption of heating and cooling of buildings has led to a demand for improved thermal performances of building materials. In this study, an experimental investigation is performed to predict the thermal insulation properties of wall and roof structures of which the mechanical properties are known, by using backpropagation artificial neural network (ANNs) method. The produced samples are cement based and have relatively high insulation properties for energy efficient buildings. In this regard, 102 new samples and their compositions are produced and their mechanical and thermal properties are tested in accordance with ASTM and EN standards. Then, comparisons have been made between the determined thermal conductivity of the newly produced structures, which are obtained from experimental method and ANN method that uses mechanical properties as input parameters. From the test results, since the percentage errors in the thermal conductivity values between experimental data and neural network prediction vary from - 1.09% to 6.4%, It can be concluded that the prediction of the artificial neural network has proceed in the correct manner.Öğe Effects of natural hard shell particles on physical, chemical, mechanical and thermal properties of composites(SAGE Journals, 2021-05-31) Çelik, Yahya Hışman; Çelik, Kadir Serdar; Kılıçkap, ErolShelled herbal foods are widely consumed. The evaluation of the shells of these foods is important due to their features such as low cost, ease of recycling and environmental friendliness. In this study, hazelnut shell (HS), pistachio shell (PS), and apricot kernel shell (AKS) were brought to powder particles by grinding to dimensions of 300–425 µm. Some of the powder particles were converted into ash at 900°C. The amounts of cellulose, ash, humidity, and metal in these particles via chemical analyses were determined, while their structural properties via X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FT-IR) analyses. Composite materials were produced by adding 15 wt.% to the polyester matrix material from these powder particles and ashes. Compression strength, hardness, specific weight, and thermal conductivity of these composites were analyzed. The lowest and highest humidity, ash, cellulose, hemicellulose, and lignin ratios in powders showed differences depending on the type of powders. The amount of Sn and K in the HS, PS, and AKS powders were close to each other, while the amount of Ca, Na, Mg, Fe, Mn, Cu, Zn and Si was higher in AKS powder. The reinforcement adding to the polyester increased the compression strength, hardness, specific weight and thermal conductivity properties.Öğe Investigation of the thermal and acoustic performance of perlite- based building materials(European Journal of Technique (EJT), 2016-12) Oktay, Hasan; Argunhan, Zeki; Doğmuş, RecepPerlite is a siliceous volcanic glass that provides heat and sound insulation, whose volume can expand substantially under the effect of heat. Perlite ore is one of the most important mineral resources for Turkey where holds a large portion reserves in the world. Evaluation of perlite in building industry, which has advantages in terms of heat and sound insulation, will make an important contribution to the national economy. In this context, experimental investigations are performed for obtaining new concrete types with relatively high strength, low density and good thermal and acoustic properties for energy efficient buildings. For this purpose, 6 sets and different types of concrete samples were prepared with a constant watercement ratio, and normal aggregates replaced by expanded perlite aggregates at different volume fractions such as 10%, 20%, 30%, 40%, 50% and 60% of the total aggregate volume. Mechanical and thermal tests were all conducted and the hot disk method was used to establish thermal property values of concrete samples. The results of the experimental studies show that the compressive strength and density decreases, while highly increases the heat and sound insulation features with increasing in perlite content. As a result, it was found out that the reductions in thermal conductivity [Wm–1K–1] and ultrasonic pulse velocity [km/s] of the produced samples reached to 75% and 35%, respectively.Öğe Characterization of hazelnut, pistachio, and apricot Kernel Shell particles and analysis of their composite properties(Taylor & Francis, 2021-05) Çelik, Yahya Hışman; Topkaya, Tolga; Kılıçkap, Erol; Başaran, Eyüp; Yalçın, RojinIn this study, hazelnut, pistachio, and apricot kernel shells were ground size of 0–300 µm, 300–600 µm, and 600–850 µm. The cellulose, ash, humidity, and metal contents of these powder particles were chemically analyzed and structural properties were characterized using X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectrometer (FT-IR) analysis. Their composites were fabricated by adding 0%, 10%, 20%, and 30% by weight of these powder particles to the polyester matrix material. The effect of chemical and structural properties of the powder particles on the physical, thermal, and mechanical properties of the composites was analyzed. The XRD analysis revealed that cellulose structure observed in powder particles. The peaks observed in their surface functional structures with FT-IR were mainly caused by cellulose and hemicellulose structures. These structures effected humidity and ash ratios. Nitrogen, carbon, hydrogen, and oxygen elements were seen in the structure. In addition, heavy metals such as Sn, Ca, K, Na, Mg, Fe, Ni, Mn, Cu, Zn, and Si were found. Powder particles added to the polyester material adversely affected the tensile strength of the matrix material. However, powder particles added to the matrix material at low rates had a positive effect on bending and compressive strength.Öğe Mechanical and thermophysical properties of lightweight aggregate concretes(Elsevier, 2015-10-15) Oktay, Hasan; Yumrutaş, Recep; Akpolat, AbdullahIn this study, experimental investigation is performed for producing new cement-based with relatively high strength, low density and good thermal properties for energy efficient buildings. Different types of concretes containing silica fume (SF), superplasticizer (SP) and air-entrained admixtures are prepared with a constant water–cement ratio, and normal aggregates replaced by lightweight aggregates (LWAs) including pumice (PA), expanded perlite (EPA) and rubber aggregates (RA) at different volume fractions of 10%, 20%, 30%, 40% and 50%. 102 samples with different materials and compositions are produced, and their characteristics are tested in accordance with ASTM and EN standards. Based on the experimental results, equations are presented to determine the relation between the thermophysical properties of composite samples. The investigation revealed that the addition of PA, EPA and RA reduced the material bulk density and compressive strength, and improved the insulation characteristics of the composite concretes. Furthermore, it was found out that the reductions in thermal conductivity and diffusivity of the produced samples reached to 82% and 74%, respectively.Öğe Investigation of the thermal performance of high insulation building materials by using light-weight aggregates(Dicle University, 2016) Oktay, Hasan; Argunhan, Zeki; Doğmuş, RecepPerlite is one of the most important mineral resources in Turkey where a large part of world reserves was estimated to be found in. Perlite is a siliceous volcanic glass that provides heat insulation. When it is expanded, it's volume increases about 30 times of the original volume. Despite the fact that Perlite is used in different areas, the most common usage is seen in the construction sector. In this context, experimental investigations are performed for obtaining new concrete types with relatively high strength and good thermal properties for energy efficient buildings. For this purpose, 6 sets and different types of concrete samples were prepared with a constant water-cement ratio, and normal aggregates replaced by expanded perlite aggregates at different volume fractions such as 10%, 20%, 30%, 40%, 50% and 60% of the total aggregate volume. Mechanical tests were all conducted and the hot disk method was used to find thermal conductivity values of concrete samples. As a result of experimental study, it was found out that the reductions in thermal conductivity of the produced samples reached to 75%. As a result, with suitable ratio usage of expanded perlite aggregate was understood to be effective on the mechanical properties and thermal conductivity of perlite aggregated light weight concrete and the relations between the mechanical and thermal properties were determined.
