大量二氧化碳排放導致全球二氧化碳濃度不斷上升，進而引發全球暖化和氣候變化，已成為當今時代最重要且迫在眉睫的議題之一。混凝土被廣泛應用於各種工程中，但生產水泥的過程卻釋放大量的二氧化碳。因此，若能夠利用混凝土將二氧化碳回收再利用並同時確保其良好的力學性質，將成為解決二氧化碳排放問題的一項有效方法。有鑑於此，本研究探討水泥漿體在新拌過程中輸入二氧化碳氣體之影響，主要可分為兩個部分。第一部分探討不同水灰比(0.4、0.5、0.6)下，不同二氧化碳流量、延後輸入二氧化碳時間及輸氣劑添加重量對抗壓強度之影響。第二部分探討各變數下之固碳效率。前者試驗結果發現，不同二氧化碳流量下，水灰比0.35試體的28天抗壓強度皆低於控制組17-25%。水灰比0.4試體的28天抗壓強度隨著流量增加而下降，流量為0.5 L/min之組別強度提升7%，流量為5 L/min之組別強度下降22%。水灰比0.5的抗壓強度與控制組接近，較無明顯影響。在不同延後輸入二氧化碳時間下，各水灰比試體的抗壓強度皆受到影響。當水灰比為0.35、延後輸入二氧化碳時間45秒時，28天抗壓強度與控制組強度接近。當水灰比為0.4、延後輸入二氧化碳時間45秒時，28天抗壓強度高於控制組強度5%。不同輸氣劑劑量添加下，當水灰比為0.4，輸氣劑添加重量從0.05%增加到1%時，28天抗壓強度從47.49 MPa降低到33.04 MPa。試驗結果亦發現，低水灰比組之碳化效率較高。在不同水灰比且流量及時間相同下，水灰比0.35的碳化效率為10.1%，而水灰比0.4、0.5的碳化效率為8.1%與5.5%。輸氣劑對於吸收二氧化碳有較好的影響。當水灰比為0.4，輸氣劑重量從0.05%增加到0.5%時，吸收效率從3.6%增加到4.5%。

Large amount of carbon dioxide emissions has led to a continuous increase in global carbon dioxide concentration, thereby triggering global warming and climate change and becoming one of the most important and urgent issues nowadays. Concrete is widely used in various engineering projects, but the process of cement production releases a significant amount of carbon dioxide. Therefore, if carbon dioxide could be captured and reused by concrete while ensuring favorable mechanical properties of concrete, it would become an effective method to resolve the issue of carbon emissions. In light of this, this study investigated the impact of introducing carbon dioxide gas into cement slurry during the mixing process, which can be mainly divided into two parts.
The first part examined the effects of different water-to-cement ratios (0.4, 0.5, 0.6), different carbon dioxide flow rates, delayed carbon dioxide introduction times, and air-entraining agent weights on the compressive strength. The second part investigated the carbon fixation efficiency under various variables. The results of the former experiments showed that under different carbon dioxide flow rates, the 28-day compressive strength of specimens with a water-to-cement ratio of 0.35 was 17-25% lower than the control group. For specimens with a water-to-cement ratio of 0.4, the 28-day compressive strength decreased as the flow rate increased. The group with a flow rate of 0.5 L/min showed a 7% increase in strength, while the group with a flow rate of 5 L/min experienced a 22% decrease in strength. The compressive strength of the specimens with a water-to-cement ratio of 0.5 was similar to that of the control group, showing minimal impact. Under different delayed carbon dioxide introduction times, the compressive strength of specimens with various water-to-cement ratios was affected. When the water-to-cement ratio was 0.35 and the carbon dioxide was introduced 45 seconds later, the 28-day compressive strength was similar to that of the control group. When the water-to-cement ratio was 0.4 and the carbon dioxide was introduced 45 seconds later, the 28-day compressive strength was 5% higher than that of the control group. With different weights of the air-entraining agent added, when the water-to-cement ratio was 0.4, the 28-day compressive strength decreased from 47.49 MPa to 33.04 MPa as the air-entraining agent weight increased from 0.05% to 1%. The results also indicated that the carbonation efficiency was higher in the low water-to-cement ratio group. Under the same flow rate and time conditions with different water-to-cement ratios, the carbonation efficiency was 10.1% for a water-to-cement ratio of 0.35, and 8.1% and 5.5% for water-to-cement ratios of 0.4 and 0.5, respectively. Air-entraining agents had a positive impact on carbon dioxide absorption. When the water-to-cement ratio was 0.4, increasing the air-entraining agent weight from 0.05% to 0.5% led to an increase in absorption efficiency from 3.6% to 4.5%.

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