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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 mechanical properties of lightweight concretes with different lightweight aggregates(Dicle University, 2019) Oktay, Hasan; Aydın, Hüseyin; Işık, Mehmet Zerrakki; Argunhan, ZekiEngineers have to know mechanical characteristics of lightweight concretes which are better than normal concretes. In this study, experimental investigations are performed for obtaining new concrete types to investigate the effect of lightweight aggregates on mechanical properties and to evaluate the relationships between the measured values of these properties. For this purpose, different types of concrete samples were prepared with a constant w/c, and normal aggregates replaced by lightweight aggregates such as pumice, expanded perlite and rubber aggregates at different volume fractions such as 10 %, 20 %, 30 %, 40 % and 50 % of the total aggregate volume. 102 samples were produced, and their mechanical characteristics were tested in accordance with ASTM and EN standards. Moreover, in order to evaluate possible correlations among the tested properties, a multivariate regression analysis was performed. Based on the experimental results, the expressions are presented to determine the relation between the mechanical properties of concrete samples. The results showed that both the compressive strengths and bulk densities of lightweight concrete samples decreased with increasing the (%) percentage of lightweight aggregate content. In addition, the regression analysis results show that if one of the mechanical properties of a structure is known, the other important properties can be calculated easily utilizing those expressions.
