Effect of alkaline carbonate-based activators on the properties of one-part ternary hybrid cement

Abstract

This paper investigates the use of solid alkaline carbonates (Na2CO3 and K2CO3) as activators for the production of one-part hybrid cement from a combination of three precursors: blast furnace slag, metakaolin, and clinker. The impact of activator dosage and the nature of the alkaline cation (Na+ or K+) on the compressive strength (Cs) and microstructure of the elaborated materials was studied. The results indicate that the highest Cs values are achieved with 5 % Na2CO3. The analysis of the reaction products’ microstructure reveals that the inclusion of Na2CO3 mainly produces (N,C)-A-S-H and C-A-S-H cementitious gels, along with metastable carboaluminates and different types of calcium carbonate. Additionally, the presence of K2CO3 results in the creation of hemicarboaluminate.