This study introduces a novel approach for in-situ CO2 sequestration using recycled concrete fines (RCFs). The method employs heterogeneous dual‑calcium carbonate (Cc) precipitation from wet carbonation and calcium bicarbonate (Ca(HCO3)2) solution to form a Cc binder between RCFs. The results demonstrate that metastable aragonite is significantly promoted and stabilized in wet carbonation by leveraging the seeding effects from semi-dry carbonated RCFs. A carbonated cement paste layer attached to the surface of RCFs facilitates the combination of precipitated aragonite crystals, while K (Na)-feldspar and quartz-based aggregates exhibit a relatively lower affinity for combining with Cc. The entanglement of aragonite crystals provides most of the strength in the carbonated RCF system. In the non‑carbonated recycled cement paste powders system, wet carbonation primarily produces calcite, while precipitation from Ca(HCO3)2 yields aragonite, forming a Cc solid skeleton that contributes to the strength.

中文翻译：

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可回收的碳酸钙基混凝土：利用碳酸钙通过原位非均相双沉淀方法粘合回收的混凝土细粉


本研究介绍了一种使用回收混凝土细粉 （RCF） 进行原位 CO2 封存的新方法。该方法采用湿碳化和碳酸氢钙 （Ca（HCO3）2） 溶液中的非均相双碳酸钙 （Cc） 沉淀，在 RCF 之间形成 Cc 粘合剂。结果表明，利用半干碳酸盐 RCF 的晶种效应，亚稳文石在湿碳化中得到显著促进和稳定。附着在 RCF 表面的碳酸盐水泥浆层有助于沉淀的文石晶体的结合，而 K （Na）-长石和石英基聚集体与 Cc 结合的亲和力相对较低。文石晶体的缠结提供了碳酸 RCF 系统的大部分强度。在非碳酸再生水泥浆粉系统中，湿式碳化主要产生方解石，而 Ca（HCO3）2 沉淀产生文石，形成有助于强度的 Cc 固体骨架。