The carbonation of OPC mortars partially substituted with spent fluid catalytic catalyst (FC3R) and its influence on their mechanical properties

Accelerated carbonation tests have been carried out on Portland cement mortars and pastes, partially substituted with a spent fluid catalytic cracking catalyst (FC3R). This study has revealed that the incorporation of FC3R on mortars produces a significant reduction of the alkaline reserve. Furthermore, it has been observed that this pozzolan also produces a reduction in the mortar porosity. When FC3R/cement system is carbonated, both portlandite and CAH/CASH are transformed, yielding calcium carbonate. When the water/binder ratio (w/b) is low, the carbonation rate of mortars is negligible and is not modified by the presence of FC3R. When the w/b ratio is medium or high, the carbonation rate raises sharply. In these cases, the presence of FC3R accelerates the carbonation process suggesting that the reduction in porosity did not compensate the reduction in the portlandite which act as chemical barrier.