本研究在混凝土新拌階段即注入二氧化碳氣體,使混凝土能與二氧化碳充分地進行反應,避免在試體表面堆積太多的碳酸鈣結晶物後,二氧化碳便難以與內部之水泥進行反應。研究中以不同的水灰比、加壓壓力與二氧化碳濃度製作混凝土試體,觀察比較這些參數對吸附二氧化碳效果的影響,最後於不同齡期檢視此方法對於混凝土的物理及化學性質上的影響。 結果顯示此研究方法確實能更有效率的吸附、儲存二氧化碳,能在短時間內充分的與二氧化碳進行反應,使水泥的凝結時間縮短;但通入二氧化碳後會造成混凝土工作性的嚴重降低,須以更高之水灰比拌合試體,以及在通入二氧化碳後其產生的化學反應會使水泥之膠結力減低,綜合這些原因使此項技術所製成的混凝土試體抗壓強度有所下降,但其強度結果依然在可接受之範圍。另外混凝土之中性化結果需要多加注意,因混凝土充分的與二氧化碳進行反應,會造成其酸鹼性的降低,未來若利用於鋼筋混凝土構造可能會引發鋼筋鏽蝕的問題,還需研擬討論,評估可行性。
In order to let concrete react with carbon dioxide sufficiently, the carbon dioxide was added to mixing concrete. The study used different W/C, CO2 pressure, and CO2 concentration to make concrete samples, and observed the effect of carbon dioxide adsorption in the above parameters. Finally, the concrete properties were tested after different curing time. The research showed that concrete could be more efficient to absorb carbon dioxide by using this method. The results found that the mixing concrete react with carbon dioxide in a short time, and shorten the initial setting time of concrete. But this method would greatly reduce the workability of concrete after mixing with carbon dioxide and it might be enhanced by the W/C or SP. The bond of cement would cut down after reacting with carbon dioxide. Based on the above, the compressive strength of concrete which was mixed with carbon dioxide would be impaired. However, the compressive strength is still acceptable. In addition, it must be noted that carbonation of the concrete and the ability of protecting reinforcement from being rusted will lost because pH value of concrete was reduced. This method needed to be assessed the durability if it is used for structure of reinforced concrete in further.