Core Project 9: EPFL, UAarhus, UNIABDN, EMPA

Title

Impact of additions on hydration kinetics

Authors

Ecole Polytechnique Fédérale de Lausanne, CH
University of Aarhus, DK
Eidgenössische Materialprüfungs- und Forschungsanstalt, CH
University of Aberdeen, Scotland, UK

Start date

January 2011

Objectives

The objectives here are to identify impact of additions on hydration kinetics and integrate into a microstructural model 

Scientific need / Link to Nanocem goals:

• Need to have mechanistic understanding of role of additions and a kinetic model to add to the thermodynamic database.
• Need to be able to adapt cementitious systems to locally available materials.
• Need to understand possible problems, due to poor aluminate sulfate balance sometimes occurring in the field. 

The background relates to 3 activities:

Core project 4 developped new methods to measure the degree of reaction of SCMs in cementitious systems

Core project 5 tried, but did not succeed to look at the reaction of syntethic glasses as a function of pH, etc.

Recent work in the EPFL partner project has led to success in modelling the hydration of mixed silicate / aluminate systems based on 2 principal mechanisms. The first period of slow down and induction period is governed by the dissolution reactions and second, the main heat evolution peak, is controlled by nucleation and growth of hydrates (C-S-H, AFm phase or etringite). Furthermore it was found that parameters derived from simple systems could be applied in more complex systems – even white cement without modification.

The idea is to extend this background to work towards a model in which we can systematically simulate the effects of additions on hydration kinetics and microstructure.