Mechanical and durability performance of ternary blended calcined clay and pulverized granite mortar composites

Partially replacing cement with pozzolans, apart from the enormous technical benefits, has been reported as an effective approach to reducing greenhouse gases emanating from cement production. Calcined clay and pulverised granite, in recent years, have been experimented individually for their use as filler or pozzolan in concrete to improve workability and compressive strength. This research includes study of the synergistic characteristics of these two mineral admixtures and their influence on the mechanical and durability properties of mortar. Cement was partially substituted with 5-20% by weight of the composite material to form a ternary blended cement composite. The compressive strengths of the ternary blended cements were evaluated at 3, 7, 28 and 90 days. Durability properties such as alkali silica reactivity (ASR), rapid chloride permeability test (RCPT) and performance of the blended cements in aggressive media have been discussed. Test results indicated that, blended cements containing 5% and 10% of the pozzolan recorded similar compressive strengths at 28 days and outperformed it by 2.4% and 0.6% respectively at 90 days. Beyond 10% replacement, compressive strengths declined. The ternary blended cements were found to be highly reactive, potentially causing ASR in concrete than the reference cement.