Effect of mixture constituents on properties of slaked lime–metakaolin–sand mortars containing sodium hydroxide

In the present study, percentage of slaked lime (20–30%) in binder with metakaolin, water–binder ratio (0.8–1.0), sand–binder ratio (1–3) and sodium hydroxide (NaOH)–binder ratio (0.02–0.04) were factors varied to investigate properties of fresh or hardened mortars. Sodium hydroxide was used as a chemical activator in the slaked lime–metakaolin binders. Properties studied after 7 or 28 days of curing mortars at 40 ± 1 °C were consistency, compressive strength and water absorption. The physical, chemical, mineralogical and pozzolanic characteristics of materials used in study were determined. It was concluded that water–binder and sand–binder ratios are the most influential factors for consistency and water absorption of mortars. Compressive strength is influenced by all mixture constituents but NaOH–binder ratios less than 0.03 are recommended for use in mortars.