Aluminum Hydroxide
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Aluminum Hydroxide is used as an accelerator in shotcrete, a type of concrete sprayed onto a surface using high-pressure air. When added to the shotcrete, aluminum hydroxide accelerates the cement hydration rate, allowing the shotcrete to set and harden more quickly. This can be useful when time is critical, such as in repair work or underground mining.
Aluminum Hydroxide is known to increase the pH level of the concrete, and when combined with specific silica-containing aggregates, it can cause the ASR reaction. Proper dosage and quality control should be exercised while using aluminum hydroxide as an accelerator. It should be used only in cases where the aggregate is known not to react with it.
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Adding Aluminum Hydroxide to aluminum sulfate in alkali-free shotcrete accelerator systems to help control the set time of the shotcrete. Aluminum Hydroxide is used to manage the setting time of the sprayed concrete, improve its strength and durability, and reduce shrinkage.
Aluminum Hydroxide acts as a filler, helping to reduce the amount of aluminum sulfate needed to achieve the desired set time. This reduces the overall amount of alumina in the shotcrete mixture, which can help reduce the risk of corrosion and other issues over time.