UÇUCU KÜLLERDEN SOĞUK BAĞLAMA YÖNTEMİYLE HAFİF-İRİ AGREGA ÜRETİMİ VE ATMOSFERİK ETKİLER ALTINDA PERFORMANSININ ARAŞTIRILMASI
Recently, several important studies focus on the recycling of industrial waste materials due to their storage problem. During last decade, usage of concrete that produced from low density natural or lightweight artificial aggregates have increased in construction sector. Considering the increases on supply and demand on lightweight aggregate included concretes along with limited resource of natural raw materials, researchers focused on producing artificial lightweight aggregate with low energy usages and environmentally friendly. Therefore, industrial wastes, such fly ashes, are being used on artificial lightweight aggregate production. In this study fly ashes, were obtained from Yatağan Thermal Power Plant, used in light-coarse aggregate production. For this aim, a mould was design that allow to produce aggregates with 18 mm diameter geometry between cube to sphere using cold binding method. Herewith, a new alternative resource for aggregate could use for the areas (e.g. construction sites) with unsuitable raw materials. Another advantage of the designed mould is to produce fly ash aggregate applying pressing method using without any binding agent or sintering. The aggregate production in this study based on homogenous mixture of mainly fly ash, Portland cement and water. The strength and availability of produced aggregates in concretes were tested several aging tests (freezing-thawing, wetting-drying, exposure external environment). Furthermore, aggregates were also produced traditional methods and the results show that fly ash aggregates have similar or quite high strength than limestone aggregates that used in conventional concretes. The fly ash aggregates that are produced by cold binding methods have approximately 5,9 MPa point load index, whereas limestone aggregates have 5,7 MPa point load index. Additionally, density of fly ash aggregates are approximately 1,83 g/cm3 and limestone aggregates are 2,69 g/cm3. The strength of fly ash included aggregate concretes (53,62 MPa) are higher than limestone aggregate ones (44,22 MPa). The density (dry and saturated), water absorption capacity and porosity of the fly ash aggregates are less than limestone aggregates. The freezing-thawing aging test, both 22 and 44 cycles, results show that the strength of concrete samples increased 1.73%. The wetting-drying test applied as 40 and 80 cycles and the strength of concrete decreased 4% after 80 cycles test. The physical characteristics and strength of both fly ash and limestone aggregates are more and less similar after 270 cycles exposure external environment test.