Than the base concrete shrinkage 1 times, alkali-free aggregate reaction hazards.
The impermeability of concrete is higher than that of alkaline set accelerator.
1.5-2 times larger than the base concrete shrinkage, alkali aggregate reaction occurs at any time.
The impermeability of concrete is lower than that of alkali-free set accelerator.
1. The content of alkaline quick-setting agent is lower than that of alkali-free set accelerator.
2. Alkaline quick-setting agent early strength slightly higher than the alkali-free set accelerator.
3. The strength of alkaline set accelerator is about 50% lower than that of alkali-free set accelerator. Thus, in the design of the same reference to the injection of concrete, the alkaline set accelerator needs to increase the amount of cement, alkali-free set accelerator can reduce the amount of cement.
4. The durability of alkali-free set accelerator is much higher than that of alkaline quick-setting agents. The alkaline set accelerator because of its high alkali content, when the active aggregate encountered, it will cause alkali aggregate reaction. After the occurrence of alkali aggregate reaction of the shotcrete, the structure becomes loose, loss of tunnel support capacity, serious may cause tunnel collapse. The alkali-free set accelerator has little alkali content and does not cause an alkali aggregate reaction. In addition, the shrinkage performance of alkali-free set accelerator is higher than that of alkaline set accelerator.