This study investigates the role of L-aspartic (L-Asp) in regulating the crystallisation of hydrated magnesium carbonates (HMCs) in carbonation-cured reactive MgO (RM). The effects of L-Asp on hydration kinetics, bulk density, compressive strength, phase composition, carbon sequestration, microstructure and morphology of RM composites were examined to understand its influence on the coupled hydration and carbonation processes. It has been found that L-Asp delays the precipitation of Mg2+ and OH−, promoting the formation and stabilisation of the metastable nesquehonite (MgCO₃·3H₂O) polymorph. Carbonated composites incorporating L-Asp demonstrate a higher carbonation degree and enhanced stability compared to those without L-Asp. Notably, samples containing 0.2 M L-Asp sequestrated 46.7 % more CO2 than those without amino acids. Additionally, amino acids lead to denser carbonation products with modified morphology, significantly enhancing carbonation efficiency and compressive strength. This study unveils the synergetic mechanism by which L-Asp influences hydration and carbonation in MgO-based binders, contributing to their enhanced performance.

中文翻译：

---

氨基酸对活性 MgO 水泥水化和碳化的协同调控

本研究探讨了 L-天冬氨酸 （L-Asp） 在调节碳酸化固化反应性 MgO （RM） 中水合碳酸镁 （HMC） 结晶中的作用。研究了 L-Asp 对 RM 复合材料水化动力学、堆积密度、抗压强度、相组成、碳封存、微观结构和形貌的影响，以了解其对耦合水化和碳化过程的影响。已经发现 L-Asp 延迟了 Mg2+ 和 OH− 的沉淀，促进了亚稳态 nesquehonite （MgCO₃·3H₂O） 多晶型物的形成和稳定。与不含 L-Asp 的复合材料相比，掺入 L-Asp 的碳酸复合材料表现出更高的碳酸化程度和更强的稳定性。值得注意的是，含有 0.2 M L-Asp 的样品比不含氨基酸的样品多封存 46.7 % 的 CO2。此外，氨基酸导致具有修饰形态的更致密的碳酸化产物，显著提高碳酸化效率和抗压强度。本研究揭示了 L-Asp 影响 MgO 基粘合剂中水化和碳化的协同机制，有助于提高其性能。