Influences of Metakaolin on the Durability and Mechanical Properties of Mortars

In this paper, the effects of the use of metakaolin instead of cement on the mechanical properties of mortars, high temperature, alkali-silica reaction, resistance to sulfate, absorption capacity and permeability were studied. In the study, 0, 5, 10, 15 and 20 % cement was replaced by metakaolin by weight to design five different types of mortar. 1-, 3-, 7-, 28-, 56-, 90- and 180-day compressive and flexural strengths and 28-day absorption capacity were determined. Similarly, compressive strength loss in mortar exposed to 200, 500 and for 3 h was determined. The resistance of mortars containing metakaolin to sulfate and alkali silica reaction was determined in accordance with ASTM C 1012 and ASTM C 1260 standards, respectively. It was found that the use of metakaolin had a positive effect on the mechanical properties of the mortars positively and that it reduced the absorption capacity and degrees of expansion caused by ASR and sulfate attack.