γ-C2S has been attracting much attention as the role of exclusive or primary binder to fabricate carbonated materials due to its high carbonation reactivity. However, the very limited hydration reactivity of γ-C2S makes it difficult in the production of casting-formed materials such as foam concrete, and this is exacerbated by the presence of bursting-prone foams in the mixture. Given the highly cementitious property of Portland cement (PC), 10 wt% of PC was added to γ-C2S-based foam concrete (CFC) as the supplemented binder to maintain its cellular structure while providing demoulding strength. The compressive strength of the CFC (600 kg/m3), carbonated for 2 h at ambient conditions, impressively peaks at 4.49 MPa, comparable to that of autoclaved aerated concrete with the same density grade, and is three times higher than the standard strength of foam concrete. This is partly attributed to the more uniform air-void size distribution formed by the enrichment of cement hydration products on the void-wall. Furthermore, the presence of cement hydration products positively promotes the dissolution of calcium ions from γ-C2S, forming a mixture of calcium and silicon products. This paper aims to understand the carbonation mechanisms of composite CFC, and also provide guidance for further realizing the reaction process associated with multiple carbonatable phases.

中文翻译：

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了解碳酸盐γ-C2S基泡沫混凝土的不均匀相分布和多步反应机理


γ-C2S 由于其高碳酸化反应性，作为制造碳酸材料的专用或主要粘合剂的作用而备受关注。然而，γ-C2S 的水化反应性非常有限，这使得在生产泡沫混凝土等铸造成型材料时变得困难，而混合物中存在易爆裂的泡沫会加剧这种情况。鉴于波特兰水泥 （PC） 的高胶凝性，在 γ-C2S 基泡沫混凝土 （CFC） 中添加 10 wt% 的 PC 作为补充粘合剂，以保持其蜂窝结构，同时提供脱模强度。CFC （600 kg/m3） 在环境条件下碳化 2 h 的抗压强度达到 4.49 MPa 的峰值，与相同密度等级的蒸压加气混凝土相当，比泡沫混凝土的标准强度高三倍。这部分归因于空隙壁上水泥水化产物的富集形成的更均匀的空隙尺寸分布。此外，水泥水化产物的存在积极促进了钙离子从 γ-C2S 中的溶解，形成钙和硅产品的混合物。本文旨在了解复合 CFC 的碳化机理，并为进一步实现与多个可碳化相相关的反应过程提供指导。