Investigation on the activating effect of Na2CO3 and NaOH on slag

This study aims to investigate the activating effect of Na2CO3 and NaOH on the workability and mechanic strength of slag-based alkali activated materials with different alkali contents and water to binder ratios. The heat release during the reaction process of slag activated with sodium carbonate and sodium hydroxide were monitored respectively to analyze the hydration process. Meanwhile, the workability and compressive strength were also tested with two types of activators (Na2CO3 and NaOH), two different dosages (5% and 7% of equivalent Na2O by slag weight) and three different water to binder (W/B) ratios (0.37, 0.45 and 0.5). The results show that the reaction process of slag activated with sodium carbonate is much slower than that of sodium hydroxide activated one, and its reaction phase happens approximately 40 h after the dissolution phase, and in all cases, sodium carbonate gives the higher fluidity and compressive strength with the same Na2O content and W/B ratio.