Ultra-low cement castable construction water addition scheme

The amount of water adding should be strictly controlled during construction of ultra-low cement castable

Ultra-low cement castable is a kind of high-grade refractory castable, the quality of raw materials is higher than other ordinary castable, mainly reflected in the low calcium content, and the using performance is much better. Moreover, the process ratio is more fine and diversified than ordinary castable. However, no matter what kind of raw materials and ratios, controlling the amount of water added during construction is the most important thing, because the amount of water added is too large, which directly affects the use cycle and performance.

The cement proportion of ultra-low cement castable, as well as other binders and low cement castable are different, there must be SiO2 ultrafine powder and a variety of compounds added, whether it is formulated and strength, will be higher than the indicators of low cement castable.

If the ultra-low cement material on site does not set, it’s proved that the amount of water is too large, if the temperature is too low, the temperature can be adjusted appropriately, if the temperature is too high, the amount of water can not be added too much, and the process ratio can only be adjusted according to the temperature in the production process, if the amount of water is too large, there will be delayed condensation.

For example, if the amount of water added is too large, there is no initial setting in 12 hours, the ultra-low cement castable is better than the low cement castable, the cement dosage is only 2.5-3%, the calcium content is between 0.2-1%, the water added in the laboratory is 2-3%, the initial setting time is about 10h; The amount of drinking water added to the site is about 4%, if the amount of water added is too large, there will be no condensation, even in 24 hours can not condense, will seriously affect the construction progress.

Therefore, during the construction process of ultra-low cement castable, the amount of water added must be strictly controlled, and the natural maintenance after forming can not be sprayed. If condensation is a normal phenomenon within 10 hours, the compressive strength after natural curing is generally 6-15Mpa, if the condensation is not or the condensation time is too long, the temperature can only be adjusted in the construction phenomenon, and the water can not be increased.