隨著全球淨零排放與永續發展議題日益受到重視，傳統卜特蘭水泥因熟料比例高且碳排放量大，已成為水泥產業減碳技術發展之重要對象。為兼顧減碳效益與經濟性，一項可行途徑為在卜特蘭水泥系統中部分摻入低碳早強膠結材料，以降低整體熟料用量並調整材料性能。硫鋁酸鈣水泥（Calcium Sulfoaluminate Cement， CSA）因燒成溫度較低且熟料礦物組成不同，相較於傳統卜特蘭水泥具有較低碳排放量與優異的早期強度發展潛力，為近年受到關注之低碳早強水泥系統。然而，CSA 純系統於成本與供料方面尚不易全面取代 OPC，故本研究採用於 OPC 系統中部分摻入 CSA 之複合膠結材設計，作為兼顧減碳與工程實務需求之折衷方案。在此類 OPC–CSA 複合系統中，CSA 的快速水化反應易導致凝結時間偏短及可施工時間不足，並對體積穩定性與長期耐久性之控制提出額外要求，亟需透過緩凝劑與礦物摻料（Supplementary Cementitious Materials， SCM）之協同調控加以改善；其對工程性質與微觀結構之影響機制仍有待進一步釐清。 本研究以 CSA 複合卜特蘭Ⅰ型水泥（OPC）、無水石膏（C）、矽灰（SF）、飛灰（FA）及高爐石粉粉（BFS）所組成之 CSA 複合膠結材系統（C50、C70）為研究基礎，探討不同緩凝劑配比及 SCM 組合對材料工程性質與耐久性之影響及改善效果。研究內容分為三個階段進行：第一階段評估單獨及複合添加不同 SCM 對 CSA 複合膠結材系統抗壓強度與硫酸鹽耐久性之影響，並透過抗壓強度試驗及硫酸鹽乾濕循環加速試驗，加速硫酸鹽侵蝕過程，以快速篩選出具有較佳安全性及耐久表現之配比；第二階段探討不同緩凝劑及其複合配比對 CSA 複合膠結材凝結時間、抗壓強度與水化放熱行為之影響，並建立適用之複合緩凝劑配比，以評估其對早期與後期強度之影響；第三階段則針對前述篩選之代表性配比，透過降低水膠比及高溫養護等措施，改善配比之強度損失，並輔以掃描式電子顯微鏡（SEM）及能量散射 X 光分析（EDS）等微觀試驗，觀察不同齡期下水化產物之形態與分布，進一步探討緩凝劑與 SCM 對微觀結構演變之影響機制。 試驗結果顯示，添加不同礦物摻料之 CSA 複合膠結材，其抗壓強度與硫酸鹽耐久性表現均受 CSA 含量、SCM 類型與用量顯著影響。其中，以 C50 系統中矽灰取代 20% OPC 之配比（C50S20-SF），以及以矽灰與飛灰合計取代 20% OPC 之配比（C50S20-SF+FA），具有較佳表現；其於抗壓強度試驗及硫酸鹽乾濕循環條件下，仍能維持較佳之強度與體積穩定性，顯示其耐久性具有明顯改善效果。進一步探討複合緩凝劑配置可知，適當組合硼砂（SB）與檸檬酸（CA）之複合緩凝系統，即 1% 硼砂（SB）＋0.1% 檸檬酸（CA），除可有效延長 CSA 複合膠結材之可施工時間外，亦能與早期抗壓強度取得良好平衡。此外，對於篩選後之代表性配比，透過降低水膠比並採用高溫養護條件，可顯著提升其抗壓強度發展；部分配比之強度表現甚至優於原先未調整者，且與微觀分析所顯示之水化產物生成量增加及結構緻密化趨勢相互呼應。 綜上所述，經由適當選配矽灰，或以矽灰搭配飛灰作為礦物摻料，並結合篩選後之複合緩凝劑系統，以及水膠比與養護條件之優化，可在兼顧工作性之下，同步提升 CSA 複合膠結材於不同齡期之抗壓強度及其於硫酸鹽環境下之耐久性，使整體系統在工程性能與長期耐久表現上皆展現出更具實務應用價值之改善幅度。;With increasing global attention to net-zero emissions and sustainable development， conventional ordinary Portland cement (OPC)， which contains a high clinker content and is associated with substantial carbon emissions， has become a major target for decarbonization in the cement industry. One practical approach to balancing carbon reduction and economic feasibility is the partial incorporation of low-carbon， rapid-hardening binders into OPC-based systems to reduce the overall clinker content while tailoring material performance. Calcium sulfoaluminate cement (CSA) has attracted considerable interest as a low-carbon， rapid-hardening cement owing to its lower clinkering temperature， distinct clinker mineralogy， and potential for rapid early-age strength development. However， the complete replacement of OPC by CSA remains challenging because of cost and supply limitations. Therefore， this study investigated OPC–CSA blended binders as a compromise between carbon reduction and engineering applicability. Nevertheless， the rapid hydration of CSA may lead to excessively short setting times， inadequate workability， and challenges in controlling dimensional stability and long-term durability. The combined effects of retarders and supplementary cementitious materials (SCMs) on the engineering properties and microstructural development of OPC–CSA blended binders therefore require further clarification. This study investigated CSA-blended Type I OPC binder systems， designated as C50 and C70， incorporating anhydrite， silica fume (SF)， fly ash (FA)， and ground granulated blast-furnace slag (BFS). The effects of different retarder dosages and SCM combinations on the engineering properties and sulfate durability of the binders were evaluated in three stages. First， the effects of individual and combined SCM additions on compressive strength and sulfate resistance were assessed using compressive strength tests and accelerated sulfate wetting–drying cycles to identify mixtures with favorable strength and durability performance. Second， the effects of individual retarders and combined retarder systems on setting time， compressive strength， and heat evolution were examined to establish suitable retarder combinations and evaluate their influences on early- and later-age strength development. Third， selected representative mixtures were further optimized by reducing the water-to-binder ratio and applying elevated-temperature curing. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) were used to examine the morphology and distribution of hydration products at different ages and to clarify the effects of retarders and SCMs on microstructural evolution. The results showed that the compressive strength and sulfate resistance of CSA-blended binders were significantly affected by CSA content as well as the type and dosage of SCMs. The C50 system in which 20% of OPC was replaced by SF (C50S20-SF)， as well as the C50 system in which 20% of OPC was replaced by a combination of SF and FA (C50S20-SF+FA)， exhibited the most favorable overall performance. These mixtures maintained relatively high compressive strength and dimensional stability during sulfate wetting–drying cycles， indicating improved sulfate durability. For retarder modification， a combined retarder system containing 1% borax (SB) and 0.1% citric acid (CA) effectively prolonged the workable time while maintaining a favorable balance with early-age compressive strength. Furthermore， reducing the water-to-binder ratio and applying elevated-temperature curing significantly enhanced strength development in the selected mixtures. In some cases， the modified mixtures achieved higher strength than the corresponding unmodified mixtures， consistent with the increased formation of hydration products and the denser microstructure observed by microscopic analysis. Overall， appropriate incorporation of SF or combined SF and FA， together with an optimized combined retarder system and suitable adjustment of the water-to-binder ratio and curing conditions， can improve the workability， compressive strength， and sulfate durability of CSA-blended OPC binders. These findings provide a practical basis for developing lower-carbon CSA composite binders with improved engineering performance and long-term durability.
