Durability of concrete containing ternary blends of high calcium fly ash and slag

This thesis investigates the performance of ternary blends containing high calcium fly ash (HCFA) and slag against: sulfate attack, alkali-silica reaction (ASR), salt scaling, and freeze-thaw damage. In addition, compressive strength, permeability and fresh properties were evaluated. In terms of sulfate attack, the performance of HCFA was significantly enhanced when slag was added to the mix, and the same was found for ASR. The high efficacy in resisting ASR of HCFA/slag blends was found to be a result of the blends' ability to bind and retain alkalis. Regarding the salt scaling, the tested ternary concretes failed the Ministry of Transportation Ontario limit, 0.8 kg/m²; however, enhanced performance was achieved when the samples were cured by wrapping with plastic sheets. Ternary blends achieved high resistance to freezing/thawing and less bleeding compared to those of the control mix without slag or HCFA; however, setting time was dragged by about an hour.