| Abstract: | 為了因應國際綠色環保潮流，響應政府節能減碳與永續發展政策，水泥產業對如何消耗收集的二氧化碳成了研究的重點項目。對此我們設計目標強度為21MPa的三種不同尺寸之圓柱混凝土試體，分別為Ф15×30 cm、Ф10×20 cm、Ф5×10 cm；以及三種尺寸的立方混凝土試體，分別是15x15x15cm、30x30x30cm、40x40x40cm，將製作好的試體放入二氧化碳濃度為50%、壓力2bar的環境中，以三種加壓時間1hr、3hr、6hr來進行混凝土的二氧化碳養護。本研究主旨為探討關於圓柱試體與立方試體在經過碳養護後的抗壓強度、尺寸效應、氯離子電滲量與凍融循環之變化。
從實驗結果可以發現圓柱試體整體在經過碳養護3hr的抗壓強度提升較高，提升約10~30%，而立方試體的部分則是在養護時間6hr的情況下提升約0~15%。經過超音波檢測顯示碳養護混凝土在早期已有規範所訂立的優良品質。在尺寸效應的部分，立方試體的碳尺寸放大係數約1.15明顯大於圓柱試體的碳尺寸放大係數1.10，顯示立方試體收到尺寸效應影響較深。凍融循環方面，一般混凝土抗壓強度下降約10~30%，而碳養護混凝土則下降約0~20%，顯示碳養護混凝土有較佳的抗凍融能力。最後是RCPT試驗，碳養護混土與一般混凝土兩者的庫倫值相當接近，代表兩者有著相同的抗氯離子能力。
;In order to respond to the world-changing green trend, energy conservation and carbon reduction, and sustainable development policies, the cement industry has become a key research project on how to consume the collected carbon dioxide. In this regard, we designed three different sizes of cylindrical specimens (namely Ф15×30 cm, Ф10×20 cm, and Ф5×10 cm) with a target strength of 21MPa, and three sizes of cubic specimens (namely 15x15x15cm, 30x30x30cm, and 40x40x40cm). The prepared samples were placed in an environment with a carbon dioxide concentration of 50% and a pressure of 2 bar, and the carbon dioxide curing of the concrete was carried out with three pressurization times of 1hr, 3hr, and 6hr. The purpose of this study is to investigate the compressive strength, size effect, chloride ion penetration and freeze-thaw cycles of cylindrical and cubic specimens after carbon curing.
From the experimental results, it can be found that the overall compressive strength of the cylindrical specimen after carbon curing for 3 hours is increased by about 10 to 30%, while the part of the cubic specimen is increased by about 0 to 15% under the condition of curing time of 6 hours. Ultrasonic testing has shown that carbon-cured concrete has the good quality established by the existing specifications in the early days. In the part of the size effect, the carbon size magnification factor of the cubic specimen is about 1.15, which is obviously larger than that of the cylindrical specimen, which is 1.10, indicating that the cubic specimen is deeply affected by the size effect. In terms of freeze-thaw cycles, the compressive strength of general concrete decreased by about 10 to 30%, while that of carbon-cured concrete decreased by about 0 to 20%, indicating that carbon-cured concrete has better freeze-thaw resistance. Finally, in the RCPT test, the coulomb values of carbon-cured concrete and general concrete are quite close, which means that they have the same resistance to chloride ions. |
