This work aims to propose a novel method to treat the defects of delayed hydration and low early-age strength of cementitious composites blended with high-volume fly ash (HVFA). The influence of calcined layered double hydroxide (CLDH) on mechanical properties, hydration process and microstructure of HVFA cementitious composites have been explored. Assessed properties of HVFA cementious composites incorporated various contents of CLDH included compressive strength, flowability, pore size distribution and the alkalinity of pore solution. The hydration process and microstructure were detected by XRD, TGA, Barrett-Joyner-Halenda Analysis (BJH), and SEM-EDS. This work revealed the promising potential of using CLDH as the hardening accelerator for HVFA composites. Results indicated that 0.5–2 wt% CLDH addition can play an important role in early-age strength increment and the HVFA mixture with 0.5 % CLDH addition performed better than other contents. In addition, microstructural analyses demonstrated an acceleration in the hydration of HVFA mortars after CLDH added, thereby higher contents of hydrated products can be observed. Meanwhile, less than 1 % CLDH addition is shown to change the morphology and composition of C-(A)-S-H to be slenderer and with higher Ca/Si ratio. Increasing the pore alkalinity by hydrolysis process and the seeding effect are the main enhancement mechanisms of CLDH.

本工作旨在提出一种新方法来处理掺入高容量粉煤灰（HVFA）的水泥基复合材料的延迟水化和早期强度低的缺陷。探讨了煅烧层状双氢氧化物 (CLDH) 对 HVFA 胶凝复合材料的力学性能、水化过程和微观结构的影响。HVFA 胶结复合材料的评估性能包括各种 CLDH 含量，包括抗压强度、流动性、孔径分布和孔隙溶液的碱度。通过 XRD、TGA、Barrett-Joyner-Halenda 分析 (BJH) 和 SEM-EDS 检测水化过程和微观结构。这项工作揭示了使用 CLDH 作为 HVFA 复合材料的硬化促进剂的潜力。结果表明，0。添加 5-2 wt% CLDH 可以在早期强度增加中发挥重要作用，并且添加 0.5% CLDH 的 HVFA 混合物比其他含量表现更好。此外，微观结构分析表明，加入 CLDH 后 HVFA 砂浆的水化加速，因此可以观察到更高的水化产品含量。同时，显示不到 1% 的 CLDH 添加会改变 C-(A)-SH 的形态和组成，使其变得更细长，并具有更高的 Ca/Si 比。通过水解过程增加孔隙碱度和种子效应是CLDH的主要增强机制。因此可以观察到更高含量的水合产物。同时，显示不到 1% 的 CLDH 添加会改变 C-(A)-SH 的形态和组成，使其变得更细长，并具有更高的 Ca/Si 比。通过水解过程增加孔隙碱度和种子效应是CLDH的主要增强机制。因此可以观察到更高含量的水合产物。同时，显示不到 1% 的 CLDH 添加会改变 C-(A)-SH 的形态和组成，使其变得更细长，并具有更高的 Ca/Si 比。通过水解过程增加孔隙碱度和种子效应是CLDH的主要增强机制。