Durability of alkali-activated fly ash cementitious materials

The study described in the present paper addresses the durability of alkali-activated fly ash (AAFA) cement under different conditions: specifically, cement performance is measured in a number of aggressive environments (deionized water, ASTM seawater, sodium sulphate and acidic solutions) and with respect to alkali–silica reaction-induced expansion. The chief parameters studied are: weight loss, compressive strength, variations in volume, presence of the products of degradation and microstructural changes. The results show that AAFA pastes perform satisfactorily in aggressive environments and that degradation in these materials is distinctly different from such processes in OPC paste. These mortars are also compliant with the 16-day expansion limit stipulated in ASTM standard C1260-94 on potential alkali– silica reactivity.