Abstract Influences of alkali or alkaline earth sulfates on the hydration of cubic tricalcium aluminate (C3A) were evaluated by in situ dissolution rate measurements, by ex situ near-surface composition measurements with secondary ion mass spectrometry, and by in situ synchrotron X-ray diffraction to monitor precipitation of hydration products. Both slight reductions in dissolution rate and cation-specific interactions with the solid were observed. The near-surface Ca/Al ratio is significantly lower after some dissolution and the electrolyte cations are incorporated within the surface with different affinities (Mg2+ > K+ > Na+). An interfacial dissolution-reprecipitation mechanism may explain the observations as well as, or better than, a simple cation exchange. The sulfate concentration in solution affects the rates of both C3A dissolution and precipitation of hydration products. Sulfate ions likely adsorb at the hydrous Al-rich surface layer, thereby reducing the dissolution rate of aluminates and delaying the precipitation of aluminate hydration products.

中文翻译：

---

铝酸三钙在低活性硫酸盐溶液中的溶解和初始水化行为

摘要 碱金属或碱土金属硫酸盐对立方铝酸三钙 (C3A) 水合的影响通过原位溶解速率测量、二次离子质谱的非原位近地表成分测量和原位同步加速器 X 射线衍射进行评估。监测水合产物的沉淀。观察到溶解速率和与固体的特定阳离子相互作用的轻微降低。一些溶解后近表面的 Ca/Al 比显着降低，并且电解质阳离子以不同的亲和力结合在表面内（Mg2+ > K+ > Na+）。界面溶解-再沉淀机制可以解释这些观察结果，甚至比简单的阳离子交换更好。溶液中的硫酸盐浓度影响 C3A 溶解和水合产物沉淀的速率。硫酸根离子可能吸附在含水的富铝表面层，从而降低铝酸盐的溶解速率并延迟铝酸盐水合产物的沉淀。