How to control the water amount of castable during construction in different seasons and temperatures
Refractory castable is a kind of amorphous refractory. It is a mixture composed of refractory aggregate, binder and admixture. It can be constructed after mixing with water (or liquid binder). The refractory castable has a certain setting and hardening time after construction, so it can be demoulded after a certain period of curing after pouring and molding, and then it can be put into baking after a proper period of natural curing.
However, during construction, the amount of water added is the key to reflect the service performance of castable.
If the ambient temperature is too high in summer, the castable will set too fast during mixing. If you still use the same amount of water as in autumn and winter, you will find that the castable is dry and loose during mixing by the sand mixer, or the setting speed is too fast and hard. Therefore, we need to increase the amount of water and add 8% – 10% more on the basis of the original amount of water. Depending on the specific situation, a small number of times can also be added; Or add retarder.
During construction in winter, if the ambient temperature is too low, the setting speed of castable mixture will slow down. At this time, it is necessary to appropriately reduce the water addition, which is also about 8% – 10% on the basis of the original water addition, and retarder can also be added. This is to prevent the castable mixture from being too thin and affecting the service performance.
The ideal mixture state can be detected by holding the mixture into a ball in your hand. The ball mixture is a complete ball without dispersion and outflow. If the mass mixture flows out of the finger joint, it indicates that the amount of water added is too much; If the mass mixture is scattered and does not form a ball, it indicates that the amount of water added is too small.
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