固化海水离子裂缝自修复剂制备及其在硬化水泥浆体中的作用机理

Seawater-ion-bound Self-healing Agents and the Working Mechanism in Cracked Hardened Cement Paste

设计了可固化海水腐蚀性离子并加速裂缝愈合的新型自修复剂,并用于制备自修复功能骨料,同时对其对混凝土中裂缝的修复机制进行探讨。结果表明:自修复剂对400μm宽裂缝24h的表面愈合率>80%,愈合速度提高3倍;在裂缝口处快速形成并使裂缝愈合的沉淀物主要为水镁石和方解石,在破裂功能骨料内部的自修复产物则为羟钙石、方解石、Friedel盐的扩散速度和沉淀物热力学平衡常数共同决定了自修复产物矿相的空间分布和矿相演变。

A self-healing agent that can bind aggressive seawater ions and accelerate the healing process was developed, which was encapsulated as artificial aggregates. The closure ratio of a 400-μm-wide crack is 80% after self-healing for 24 h in seawater by using the self-healing agent, which is 4 times greater than that in referenced specimens. The reaction products formed at the crack mouth are mainly brucite and calcite, while in the aggregates intersected by the crack there are portlandite, calcite, Friedel’s salt, ettringite and hydrotalcite, indicating that the aggressive ions can be bound by the self-healing agent. The mineralogy and distribution characteristic of the reaction products are dependent on the diffusion of the ions dissolving from the agents and the thermodynamic equilibrium constants of the reaction products.