Sulfaattisementin

Sulfaattisementin, also known as expansive cement or shrinkage-compensating cement, is a type of cementitious material designed to counteract the natural shrinkage that occurs when concrete hardens. This shrinkage can lead to cracking, compromising the structural integrity and durability of concrete elements. Sulfaattisementin achieves this expansion by incorporating specific additives, primarily calcium sulfoaluminate clinker and calcium sulfate (gypsum).

When mixed with water, these components react to form ettringite, a crystalline compound that occupies a larger volume than the original reactants. This controlled expansion occurs during the setting and early hardening stages of the concrete. The expansion effectively counteracts the drying shrinkage, resulting in a more stable and crack-free concrete.

The use of sulfaattisementin is particularly beneficial in applications where minimizing cracking is critical, such as in large structural slabs, bridge decks, precast elements, and repairs. It helps to reduce the need for control joints and provides enhanced watertightness. However, the precise mix proportions and curing conditions are crucial for achieving the desired expansion and ensuring optimal performance. Improper handling can lead to excessive expansion or insufficient compensation.