Concrete Sulphate Resistance

Concrete Sulphate Resistance

Water containing sulphate sometimes occurs in soil or is dissolved in ground water and can attack the hardened concrete.

Process

Water containing sulphate combines with the tricalcium aluminate (C3 Al) in the cement to form ettringite (also thaumasite under certain conditions), which leads to increases in volume and to high internal pressure in the concrete structure and therefore cracking and spalling occurs.

Measures

Concrete structure as impermeable as possible

Low water/cement ratio

Use cement with a minimum tricalcium aluminate (C3 Al) content

Curing suited to the structure

Note: Clarification of specific requirements is essential for every project. Limiting values for exposure classification of chemical attack from natural soil and ground water: