Ultra-high performance (fibre-reinforced) concrete (UHPC) is recognised for its mechanical properties, such as tensile strain hardening, and exceptional durability, including autogenous healing capabilities due to, among others, the addition of supplementary cementitious materials and fibres. However, it is unknown how the cracked concrete can deal with freeze-thaw (FT) cycles with de-icing salts and if healing agents added to the mix could improve the durability of this type of concrete. This study investigates the influence of a crystalline admixture (CA) in UHPC under FT conditions with focus on single cracks with a width of around 120 μm, specifically focusing on the ability of the healing products of CA to survive and the ability to re-heal after a healing regime following FT exposure. The results revealed that UHPC incorporating healing agents exhibited remarkable resilience against cyclic FT conditions. These healing agents successfully generated healing products that provided exceptional resistance to FT-induced damage and demonstrated the capability to undergo re-healing after exposure to FT.

中文翻译：

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除冰盐循环冻融条件下超高性能自修复混凝土中的弹性结晶外加剂

超高性能（纤维增强）混凝土 (UHPC) 因其机械性能（例如拉伸应变硬化）和卓越的耐久性（包括由于添加辅助水泥材料和纤维而产生的自愈合能力）而受到认可。然而，目前尚不清楚开裂混凝土如何使用除冰盐应对冻融（FT）循环，以及在混合物中添加修复剂是否可以提高此类混凝土的耐久性。本研究研究了 FT 条件下 UHPC 中结晶混合物 (CA) 的影响，重点关注宽度约为 120 μm 的单裂纹，特别关注 CA 愈合产物的存活能力和再愈合能力FT 暴露后的治疗方案后。结果表明，掺有修复剂的 UHPC 对循环 FT 条件表现出显着的恢复能力。这些愈合剂成功地产生了愈合产品，对 FT 引起的损伤具有出色的抵抗力，并表现出在暴露于 FT 后进行重新愈合的能力。