| 摘要: | 本研究針對都市垃圾焚化飛灰進行熔融實驗，並以其熔渣粉體調製不同配比之熔渣單礦物漿體及五種不同型別之熔渣水泥漿體，以探討熔渣單礦物漿體之卜作嵐反應行為及實際應用於五種不同型別水泥之工程適用性與卜作嵐反應特性。本研究之實驗分成三部份，首先探討都市焚化飛灰在1400℃ 下經30分鐘熔融後之熔渣特性；並以其熔渣粉體備製不同配比之熔渣單礦物漿體，分析其於不同養護齡期之卜作嵐反應行為，包括抗壓強度、水化放熱行為、水化程度、晶相、物種及微結構變化等；最後並針對其熔渣粉體取代五種不同型別水泥之工程材料特性與卜作嵐反應特性作一探討。 實驗結果顯示，熔渣可降低矽酸三鈣與鋁酸三鈣水化放熱之溫度。而由DTA分析結果顯示，熔渣可延緩鋁酸三鈣由六方相C4AH13轉為立方相C3AH6之時間，且晚期以穩定之立方相C3AH6為主。另外由XRD分析結果顯示，熔渣矽酸三鈣與熔渣矽酸二鈣漿體於養護晚期（60∼90天），因卜作嵐反應消耗CH生成CSH膠體與CAH鹽類，且熔渣成分中以Si2+、Al3+對矽酸三鈣之卜作嵐反應影響較大，且熔渣可減緩石膏與鋁酸三鈣形成AFt與AFm之機會，可延緩鋁酸三鈣之初期水化。由NMR分析結果顯示，熔渣矽酸三鈣初期水化程度具延緩之趨勢，而晚期因卜作嵐反應則呈現加速之趨勢，此外，熔渣矽酸三鈣漿體之聚矽陰離子長度隨齡期增而有增加之趨勢，且較純矽酸三鈣漿體為長。五型別熔渣水泥漿體之抗壓強度，於養護早期隨熔渣取代量之增加而減小，晚期強度則呈明顯上升之趨勢；且熔渣取代量（10%、20%）者超越或接近各型純水泥；而以MIP分析結果得知，孔隙分布由毛細孔隙轉換成膠體孔隙，而總孔隙體積與毛細孔隙體隨齡期之增加而逐漸減少，且膠體孔則隨齡期之增加而有增加之趨勢，顯示熔渣晚期具卜作嵐反應特性，可提高晚期強度。 This study investigated the pozzolanic reactions and engineering properties of slag blended cements (SBC). In this work, SBCs were prepared by blending slag, which was generated from the melting of municipal solid waste incinerator fly ash (referred to as MSWFS), with five types of cements, respectively. Major cement constituents such as C3S (i.e., 3CaO.SiO2) and C3A (i.e., 3CaOAl2O3) were also used alternatively in replacement of cement for contrast. The experiments were divided into three parts: (1) characterization of the slag prepared by melting the MSW incinerator fly ash at 1400℃ for 30 min; (2) assessment of the pozzolanic reaction in the SBC pastes incorporating C3S and C3A with blend ratio ranged from 10% to 40% at various curing ages; and (3) evaluation of the effects of slag on pozzolanic reaction in the SBC pastes for five cements at various curing ages, focusing on their compressive strength, hydration heat behavior, hydration degree, crystalline speciation, and variation of microstructure. The results showed that lower hydration heat of C3S and C3A samples with the incorporation of MSWFS was observed, possibly due to the partial replacement of the mineral constituents by the slag with less activity. In general, the incorporation of slag into C3S and C2S, respectively, decreased the initial hydration reaction whereas increased the pozzolanic reaction at later stage by consuming CH to form CSH and CAH. This was evidenced by the DTA results, which showed a delayed transformation of C3A from C4AH13 to C3AH6. Moreover, hydration degree and the average length of C-S-H, (i.e., the number of Si of linear poly silicate anions in C-S-H gel, Psi) as determined by applying nuclear magnetic resonance (NMR) techniques also indicated a delayed initial hydration and an enhanced later pozzolanic reaction. In the C3S-slag paste, the Psi value increased with increasing curing age as compared with that of the C3S paste. The results of x-ray powder diffractometer (XRPD) revealed that the pozzolanic reaction in C3S-slag paste was mainly affected by the Si2+ and Al3+ released by the slag. On the other hand, the incorporation of slag delayed the initial hydration of C3A in C3A-slag paste, and decreased the formation of ettrigite (AFt) and monosulfoaluminate (AFm) in C3A-gypsum-slag paste. The early unconfined compressive strength (UCS) of SBC pastes for five types of cement were found to decreased with increasing slag blend ratio, whereas the later strength increased. In addition, the UCS for all types of SBC pastes tested with slag blend ratio<20% outperformed that of their pastes without slag. Moreover, the results of mercury intrusion porosimetry (MIP) analysis indicated that the total and the capillarity pore volume decreased with increasing ages, whereas the gel pore volume increased, showing the later pozzolanic nature of the pulverized fly ash slag. |
