Jeopolimer esaslı gözenekli hafif yapı malzemelerinin geliştirilmesi

Autoclaved aerated concrete, pumice blocks and clay-bricks are mainly preferred as construction materials in our country. Although clay-brick has superior mechanical properties among these three construction material, its thermal conductivity coefficient is higher. Aerated concrete and pumice blocks are new generation construction materials and their mechanical properties lower than clay-bricks. However, thermal conductivity coefficients of these materials are much lower than clay-bricks. Therefore, they are increasingly more preferred. In this study, fly ash from power plant was used for geopolymer production. Geopolymers were shaped using replication method. Therefore, an alternative construction material with lower thermal conductivity was investigated. Investigated geopolymers were subjected to three different temperatures (650, 850 and 1050°C). The effects of sintering temperatures on geopolymerization and thermal conductivity were investigated. In this study, Fly ash was supplied from Soma powerplant, in Manisa. NaOH was used for alcali activation. Metakolin was used for supporting geopolimerization and was supplied from Kaolin Endüstriyel Mineraller Co., in Istanbul. Metakalolin was also used as a source of Alumina- Silicate. Kuvars was supplied from Refsan Co., in Kutahya. Specimens were obtained by coating on polymer sponge by the dipping technique (replication method). Replication method provides increase in water absorption and porosity. Because sponge removed from body at 650ºC. The increase in porosity with removing of sponge ensures decrease in thermal conductivity of investigated geopolymers (J-650, J- 850 and J-1050) compared to standard geopolymer body. However, increases in sintering temperatures have negatively effect on thermal conductivity. As the sintering temperature increase, thermal conductivity increases, due to increased densification. Densification resulted in decrease in porosity of investigated bodies. Increase in sintering temperature was also responsible for new phase formations such as gehlenite and anorthite. New phases, gehlenite and anorthite, ensure an increase in mechanical strength. Microstructural analyses were conducted by scanning electron microscope and energy-dispersive X-ray spectroscopy (SEM-EDX). According to SEM and EDX figures of J-650, Quartz crystals embedded in a gel structure. Na+ was obtained from flyash and NaOH, Ca+2 was obtained from calcite and limestone, Al+3 and Si+2 were obtained from metakaolin. SEM and EDX figures of J-850 and J-1050 show quartz, gehlenite and anorthite crystals embedded in a gel structure. Ca+2 was obtained from gehlenite and anorthite. Gehlenite and anorthite was formed by decomposition of calcite and limestone. Therefore, this study shows that replication method for lightweight geopolymer construction materials is suitable. Alternative studies on foaming of geopolymers are important to decrease thermal conductivity of geopolymers. Studies are ongoing on the alternative materials (H2O2 and Aluminium powder) which will support the formation of foam.