| 초록 |
Ordinary Portland Cement (OPC) has been most widely used for building and construction materials, but it has been reported that the strength of OPC becomes deteriorated in the high temperature such as ≥ 600℃, while geopolymer cement formed with the co-polymerization of alumina and silicate species keeps better thermal durability than OPC because of its stronger compressive strength inducing inorganic framework. Hence, we manufactured coal fly (mean particle size=32.9 μm) and bottom (mean particle size=206.7 μm) ash hybrid geopolymer under the alkali activator of 14M NaOH solution with increasing the liquid to solid ratio from 0.18 to 0.26 by monitoring its not-a-gel state. The geopolymer paste samples in a 5cm cubic mold were demolded just before placing in a dry oven at 75℃ for 24 hours, and then the cured samples were irradiated in 700W microwave for 3 minutes before putting in a furnace where three kinds of test specimens were prepared by exposing at 300, 600 and 900℃, respectively, at an incremental rate of 8℃/min. The residual compressive strength was measured after cooled in ambient air. The test specimens were also analyzed by using SEM and XRD. |
