游离氧化钙对水泥浆体体积膨胀的影响机制

Effect of free CaO on the volumetric expansion of cement pastes

硬化水泥浆体由于水泥中游离氧化钙水化常会导致体积膨胀。研究发现 ,浆体的体积膨胀除与fCaO的含量和活性有关外 ,还与浆体的结构和性能密切相关。fCaO水化形成Ca(OH)2 时 ,不仅固相体积增加 ,而且空隙体积亦增加。fCaO在浆体硬化结构形成之后水化 ,且其水化产物成堆聚集时才会导致浆体体积膨胀。

Hydration of free lime often leads to a volumetric expansion of hardened cement pastes. The research results indicate that this expansion corresponds not only with the content and reactivity of free lime but also with the structure and performance of hardened pastes. The formation of Ca(OH)2 by the hydration of free lime results in the increase in the solid volume as well as in the void volume. Only when the hydration of free lime takes place after the formation of hardened pastes structure and the portlandite hydrate accumulates lead to a volumetric expansion of the pastes.