https://www.csacement.com/products/high-alumina-cement.html 1. Physical properties of high alumina cement High alumina cement is black in color and develops very fast in strength. About 80% of the ultimate strength is developed after 24 hours, and even 8 hours is strong enough to remove the formwork. The high growth rate of strength is due to its rapid hydration. It also has a high calorific value.All Rights Reserved