本研究嘗試以重量比為變數來探討飛灰取代無機聚合物中變高嶺土的可行性。初期試驗首先直接將飛灰以0% ~100%的重量比例取代變高嶺土,測試其物理性能與抗壓強度等力學性能。但因飛灰取代量過多的材料流度會大增,不易灌模成形,故再嘗試以減少氫氧化鈉水溶液中水量的方式製作試體。最後則對所有配比材料皆進行減少水量試驗,以瞭解整體效應。試驗結果顯示當飛灰取代無機聚合物中變高嶺土重量比在50%至75%之間效果較佳,其抗壓強度較其他提升最多,比重、吸水率及乾縮量等性能亦屬良好。以工作度而言,流度值在63%至100%之間為適宜區間。減少氫氧化鈉水溶液中之水量有提高鹼濃度效果,對鍵結強度有正面影響,因此以飛灰取代無機聚合物中變高嶺土確實具有新材料的潛力。
The present study attempted to find the feasibility of replacing the metakaolin composition of the original geopolymer by fly ash. At first, portions by weight from 0% to 100% of metakaolin were replaced to test their physical as well as mechanical properties. However, it was found that the flowage of the new material was too much to form the test specimens if the fly ash was increased. Thus another attempt was followed by reducing the quantity of water of the NaOH solution. Finially, the procedure of reducing water was tested on all the formula to investigate the effect in a whole. The results revealed that the satisfactory proportions of replacing metakaolin by fly ash were 50% to 75%, which gave better compressive strength than the others, and the physical properties were also acceptable. The range of flowage 63% to 100% showed a suitable workability. Reduction of water in NaOH solution might increase the concentration of alkalinity and thus would help in strength. It is seen that replacing the metakaolin composition of the geopolymer by fly ash may be a potential material in the future.