Impact of cellulose ethers on hydration of low clinker cement

Abstract

In line with the Global Cement & Concrete Association's Path to Zero roadmap, the dry‐mix industry promotes more sustainable low‐clinker formulations with supplementary cementitious materials (SCMs). Cellulose ethers (CEs) are performance additives in tile adhesive mortars that enhance workability and adhesion but retard hydration. As their interaction mechanisms in SCM‐rich systems is insufficiently understood we investigate the influence of CE molecular structure on hydration kinetics and bonding strength in tile adhesives where approximately 50% of Portland cement is replaced by limestone, or ground granulated blast furnace slag. Hydration behavior and setting are evaluated using isothermal calorimetry and Vicat testing, and adhesion via pull‐off tests after 1, 2 and 28 days. A mathematical fitting approach is developed to quantify CE‐induced changes in hydration kinetics. The results show structure–retardation relationships known for CEM I systems remain valid with a strong correlation between the degree of substitution of CEs, hydration kinetics, and bonding strength.