爐石與飛灰應用對混凝土碳封存影響之研究

Abstract

隨著全球碳排放量持續增加，全球暖化問題日益嚴重，水泥與混凝土產業面臨淨零排放的轉型壓力。為減少碳足跡，近年積極研究卜作嵐材料取代水泥與碳封存技術，兼具改善工作性、耐久性與減碳效果。其中一項碳封存技術為利用水泥與二氧化碳產生碳化反應形成碳酸鈣堆積於混凝土表層，可同時實現碳封存與增加早期強度的雙重效益。 本研究在試體早期硬固階段採用二氧化碳高壓養護方式進行碳封存，為了探討二氧化碳養護對水膠比、卜作嵐材料取代率（爐石、飛灰）與碳化養護時間等參數的影響。因此試驗設計以不同水膠比搭配不同卜作嵐材料取代率，於試體完成初期模內水化後進行預處理促使孔隙中部分水分散失，利於後續二氧化碳進入試體反應，再進行不同時間的二氧化碳養護，主要觀察項目包含以重量差異法計算的二氧化碳吸收量、碳化深度、碳化後抗壓強度及後續養護齡期的強度成長，另外搭配熱重分析TGA測量其碳酸鈣含量作為參考，來驗證重量差異法的準確性。最後本研究希望藉由試驗結果數據分析與互相驗證，來探討不同配比搭配碳化養護時間對碳封存效果與力學性質的影響機制，並評估其應用可行性。

As global carbon emissions continue to rise, the issue of global warming is becoming increasingly severe, cement and concrete industries under significant pressure to transition toward net-zero emissions. To reduce carbon footprints, recent research has focused on the use of pozzolanic materials to partially replace cement and the development of carbon sequestration technologies, which aim to improve workability, durability, and carbon reduction. One promising method involves inducing a carbonation reaction between cement and carbon dioxide to form calcium carbonate deposits on the concrete surface, achieving both carbon sequestration and early-age strength enhancement. In this study, carbonation curing under high pressure was applied during the early hardening stage of mortar specimens to evaluate the effects of carbonation on key parameters including water-to-binder ratio, pozzolanic material replacement level (slag and fly ash), and carbonation duration. The experimental design involved various mix proportions, where specimens were subjected to initial in-mold hydration, followed by pre-conditioning to partially remove internal moisture and promote CO₂ diffusion. Carbonation was then conducted for different durations. The main observations included CO₂ uptake calculated using the mass-gain method, carbonation depth, compressive strength after carbonation, and strength development during subsequent curing. Thermogravimetric analysis (TGA) was also conducted to measure calcium carbonate content and validate the accuracy of the mass-difference method. Through experimental data analysis and cross-verification, this study aims to clarify the influence of different mix proportions and carbonation durations on carbon sequestration performance and mechanical properties, and to evaluate the feasibility of the proposed approach for practical applications.