Influence of non-flowing model sulphate solution determined for cement mortar with pozzzolana admixture are presented in this paper. In the predetermined time intervals the influence of the aggressive liquid on chemical properties and mineralogical composition was tested. The changes caused by corrosive sulphate environment on the testing specimens were determined in dependence on the different type of cement and used ground clay brick as pozzolana admixture. From the results obtained follows that the additive of ground clay bricks has positively impact on the sulphate resistance.