粉煤灰在复合胶凝材料水化过程中的作用机理

分析了粉煤灰在复合胶凝材料水化硬化过程中的作用。探讨了化学激发、物理激发和热激发对于粉煤灰的活性的促进作用以及确定粉煤灰反应程度的方法。粉煤灰的火山灰活性可以用碱性物质或硫酸盐来激发,但是,这种化学激发措施不适合在商品混凝土生产过程中使用。物理激发和热激发是两种简单实用的提高粉煤灰使用效能的技术路线。热激发特别适用于大体积混凝土结构。在复合胶凝材料中,粉煤灰的反应程度很低,不会大量消耗Ca(OH)_2,在水化硬化初期,矿物掺和料主要以物理填充作用参与复合胶凝材料的水化硬化过程;随龄期延长,粉煤灰的火山灰活性作用逐渐明显。

MECHANISM OF FLY ASH'S EFFECTS DURING HYDRATION PROCESS OF COMPOSITE BINDER

The effect of fly ash during the hydrating and hardening process of composite binder was studied.The enhancing effect of chemical,physical and thermal stimulation on the reactivity of fly ash was also analyzed.Methods for determining the reaction degree of fly ash were introduced.The pozzolanic reactivity of fly ash can be activated by alkaline substances and sulfate,but chemical activation is not appropriate for use during the production of ready-mixed concrete.Physical and thermal activation are two effective techniques to enhance the efficiency of fly ash.Thermal stimulation is especially suitable for massive structures.Ca(OH)_2 is not consumed heavily when composite binder is hydrated due to the low degree of fly ash reaction.Mineral admixture participates in the hydration process of composite binder with a physical filling effect in the initial period.The pozzolanic reactivity of fly ash increases gradually with the extension of hydrating time.