水泥土环境中粉煤灰水化与活性激发研究

Research on hydrating process and solidification of fly ash in soil-cement and approach to activation

水泥—粉煤灰与土充分拌合条件下,经过初级和次级2个过程形成水泥土固结体。粉煤灰的活性效应较之形态效应和微集料效应对水泥土强度的贡献是显著和持久的。活性激发剂———粉状硅酸钠溶出的OH-对粉煤灰网络聚合度比较高的“硬壳层”有腐蚀作用,同时硅酸钠水解产生的SiO32-在水化环境中可阻止水化硅酸钙生成过多而沉积在粉煤灰表面。通过构建粉煤灰在水泥土环境中的水化模型及SEM、力学性质等测试手段,分析了粉煤灰的水化与固结特性。

After primary and secondary process,the soil-cement is coming into being on condition that the soil and cement mixed completely.Fly-ash is contributed the improvement the strength of soil-cement in three aspects.The activity effect is more important and persistent than the shape and micro-grain effect.OH-that dissolved from activator-sodium silicate can erode the net polymer that covering on the fly ash.Meanwhile,SiO2-3coming from the hydration of sodium silicate can hold back creating more hydrated calcium silicate that deposited on the surface of fly ash.Based on the hydration mechanism of fly ash,the activator is selected,and the hydrating hypothesis of fly ash in the cement soil is approved farther.The viewpoint that the activator offers OH-and captures Ca2+ and promotes the reaction of fly ash in cement soil is put forward.Meanwhile,the testing results of SEM,quantity of hydrating heat,resisting pressure intension and resisting break intension are enumerated.