Alkali-aggregate reaction in alkali-activated cement concretes

Abstract

The paper discloses the results of a study on structure formation processes in the interfacial transition zone "cement stone - aggregate" of the alkali-activated cement concretes. The results indicate the importance of the content of Al2O3 in the cement and aggregate. Together with components that are able to interact actively with alkalis in the presence of reactive SiO2, the processes taking place during the alkali-aggregate reaction can have weather destructive or constructive effect. The constructive effect is caused by incorporating the corrosion products into alkaline aluminosilicate compounds, thus retarding the internal corrosion of the concrete and providing the higher durability even in case of alkali-activated cements and alkali-susceptible aggregates with relatively high alkali content.