Time-resolved monitoring of cement hydration: Influence of cellulose ethers on hydration kinetics

Brilliant synchrotron radiation combined with a new micro-strip detector enables fast in situ measurements at the Materials Sciences beamline of the Swiss Light Source SLS at the Paul Scherrer Institut. Early hydration processes of Portland cement and the retarding effect of cellulose ether (CE) were monitored with a time resolution of 10 s. Cellulose ethers inhibit cement hydration in a phase- and CE-specific manner. The degree of substitution (DS), a major parameter of CE-characterization, is the most relevant factor whereas other characteristics such as molecular weight (MW) and CE-chemistry play minor roles in terms of retardation. The lower the DS the stronger the retardation of C2S/C3S-hydration.