Studying the Hydration of Different Celitement Samples by ATR‐FTIR Spectroscopy

Abstract

The hydration of three types of the hydraulic, amorphous, C‐S‐H‐based binder Celitement with differing strength development was investigated using isothermal heat flow calorimetry, thermogravimetric analysis and in situ as well as ex situ ATR‐FTIR spectroscopy. The investigated binders were optimized either for early‐age compressive strength (> 25 MPa, 1d), for high final compressive strength (> 85 MPa 28d), or for a compromise between both.

Differences in hydration kinetics were reflected in the heat flow curves and correlated with strength development. Data from thermogravimetric analysis showed good correlation between the formation of a C‐S‐H phase and the late‐age strength. ATR‐FTIR spectroscopy provided direct insight into the chemical and structural evolution of C‐S‐H during hydration. In particular, the formation of initially short‐chained C‐S‐H followed by progressive silicate chain polymerisation was observed.