发表机构
Rice University; Rice Advanced Materials Institute (RAMI), Rice University; Ken Kennedy Institute, Rice University（莱斯大学; 莱斯先进材料研究所; 肯·肯尼迪研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过掺入不同量Na2CO3调控碱度持续性，促进超高掺量矿渣-水泥体系中的矿渣反应，提高反应程度和强度，并降低66-72%的全球变暖潜势。
AI 中文摘要
超高掺量矿渣-水泥（UHVS）共混物可大幅降低熟料比例，但矿渣反应缓慢限制了强度发展；Na2CO3 是一种苛性较低且低碳的碱激发材料活化剂，但其中等碱度同样可能延缓强度发展。本研究将干混 Na2CO3（相对于水为 0-20 wt.%）掺入含 90 wt.% 粒化高炉矿渣和 10 wt.% 波特兰水泥（PC）的单组分胶凝材料中，以探究该整合能否缓解两种体系中缓慢的强度发展。结合抗压强度测试、等温量热法、时间分辨定量 X 射线衍射、傅里叶变换红外光谱、水溶液分析和热力学建模，确定了 Na2CO3 如何控制相组合、碱度、计算孔隙率和强度发展。在 5-10 wt.% Na2CO3 下，以方解石为主的碳酸盐反应促进了碱度的快速升高，并加速了早期反应和强度发展；然而，随后的碱度下降限制了后期矿渣反应和凝胶形成。相比之下，20 wt.% Na2CO3 有利于早期大量形成钙水碱和碳酸盐-AFm 相，这缓和了初始 pH 升高并延迟了早期凝胶积累。更大的碱储量和不断演化的相-溶液分配有助于在后期维持碱度，使矿渣持续溶解和凝胶形成。该路径产生了更高的反应程度和更低的计算孔隙率，抗压强度接近纯 PC。筛选级摇篮到大门生命周期评估表明，相对于 PC，全球变暖潜势降低了 66-72%，具体取决于 Na2CO3 的生产途径。这些结果确定了碳酸盐介导的碱度持续性控制是维持 UHVS 体系中矿渣反应的关键。
英文摘要
Ultra-high-volume slag-cement (UHVS) blends can substantially reduce clinker ratio, but slow slag reaction limits strength development; Na2CO3 is a less caustic and lower-carbon activator for alkali-activated materials, yet its moderate alkalinity can similarly delay strength development. Here, dry-blended Na2CO3 (0-20 wt.% relative to water) was incorporated into a one-part binder with 90 wt.% ground-granulated blast-furnace slag and 10 wt.% Portland cement (PC) to determine whether this integration could mitigate slow strength development in both systems. Compressive strength testing, isothermal calorimetry, time-resolved quantitative X-ray diffraction, Fourier-transform infrared spectroscopy, aqueous solution analysis, and thermodynamic modeling were combined to determine how Na2CO3 controls phase assemblage, alkalinity, calculated porosity and strength development. At 5-10 wt.% Na2CO3, calcite-dominated carbonate reactions promoted a rapid alkalinity increase and accelerated early-age reaction and strength development; however, subsequent alkalinity decline limited later-age slag reaction and gel formation. In contrast, 20 wt.% Na2CO3 favored substantial early formation of gaylussite and carbonate-AFm phases, which moderated the initial pH rise and delayed early gel accumulation. The larger alkali inventory and evolving phase-solution partitioning helped sustain alkalinity at later ages, enabling continued slag dissolution and gel formation. This pathway produced higher reaction extent and lower calculated porosities, with compressive strength approaching that of neat PC. Screening-level cradle-to-gate life-cycle assessment indicates a 66-72% reduction in global warming potential relative to PC, depending on Na2CO3 production pathways. These results identify carbonate-mediated control of alkalinity persistence as key to sustaining slag reaction in UHVS systems.
