Expansion Sulphate attack Expansive cements

Destructive expansion from reaction with sulphates can occur not only if the latter are present in excessive proportion in the cement, but also from attack on concrete by sulphate solutions. The reaction involves the Al,0,-containing phases in the hardened cement, and in sulphate-resisting Portland cements, its effects are reduced by decreasing the proportion of the aluminate phase, sometimes to zero. This is achieved by decreasing the ratio of AljOj to Fe203 in the raw materials. In the USA, sulphate-resisting Portland cements are called Type V cements. 

The resistance of expansive concrete to the sulphate solutions attack depends on the type of cement. Only the concrete of K cement type has high sirlphate resistance [64]. 

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