This study investigated composite cements with recycled concrete pastes (RCP) and the carbonated analogue, comparing them to Portland and limestone cements. The carbonation curing resulted in a carbonation degree of around 30%. The presence of supplementary cementitious materials had little impact on the carbonation degree and phase assemblage. Cement pastes consisted of ettringite, calcium carbonate, C-S-H phase and silica gel. This phase assemblage transformed upon further hydration. The alumina-silica gel from cRCP did not contribute significantly to the reactions but modified porosity. The hydrates from RCP carbonated, however did not contributed to the strength evolution. Still, replacing limestone with RCP positively contributes to environmental sustainability by increasing CO₂ sequestration. Composite cements had lower strength, but those with carbonated RCP showed higher compressive strength and faster strength evolution. This effect was related to the appreciable porosity distribution compensating for the clinker dilution impact and a fast clinker hydration during the post carbonation curing.

中文翻译：

---

使用回收辅助胶凝材料对波特兰水泥进行碳化硬化


本研究调查了含有再生混凝土浆料 （RCP） 和碳酸盐类似物的复合水泥，将它们与波特兰水泥和石灰石水泥进行了比较。碳化固化导致碳化度约为 30%。补充胶凝材料的存在对碳化程度和相组合影响不大。水泥浆由钙矾石、碳酸钙、C-S-H 相和硅胶组成。这个阶段组合在进一步水化后发生了变化。来自 cRCP 的氧化铝硅胶对反应没有显着贡献，但改变了孔隙率。然而，来自 RCP 碳酸化的水合物对强度的演变没有贡献。尽管如此，用 RCP 代替石灰石通过增加 CO₂ 封存对环境可持续性做出了积极贡献。复合水泥的强度较低，但碳酸盐 RCP 的复合水泥表现出更高的抗压强度和更快的强度演变。这种影响与补偿熟料稀释影响的明显孔隙率分布和碳化后固化过程中熟料的快速水化有关。